WO2023184496A1 - 二次电池、电池模块、电池包和用电装置 - Google Patents

二次电池、电池模块、电池包和用电装置 Download PDF

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WO2023184496A1
WO2023184496A1 PCT/CN2022/084859 CN2022084859W WO2023184496A1 WO 2023184496 A1 WO2023184496 A1 WO 2023184496A1 CN 2022084859 W CN2022084859 W CN 2022084859W WO 2023184496 A1 WO2023184496 A1 WO 2023184496A1
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secondary battery
group
optionally
active material
range
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French (fr)
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张立美
陈培培
彭畅
刘姣
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Priority to EP22930129.6A priority Critical patent/EP4293777A4/en
Priority to CN202280016850.3A priority patent/CN116897453B/zh
Priority to JP2023547875A priority patent/JP7646851B2/ja
Priority to PCT/CN2022/084859 priority patent/WO2023184496A1/zh
Priority to KR1020237026887A priority patent/KR102941244B1/ko
Publication of WO2023184496A1 publication Critical patent/WO2023184496A1/zh
Priority to US18/608,952 priority patent/US20240274810A1/en
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    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H01M4/1315—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx containing halogen atoms, e.g. LiCoOxFy
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    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
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    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
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    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • C—CHEMISTRY; METALLURGY
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    • H01M2004/028—Positive electrodes
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    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of lithium batteries, and in particular to a secondary battery, a battery module, a battery pack and an electrical device.
  • lithium-ion batteries are widely used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, Military equipment, aerospace and other fields. Due to the great development of lithium-ion batteries, higher requirements have been put forward for their energy density, cycle performance and safety performance.
  • lithium manganese phosphate cathode active materials Compared with other cathode active materials, lithium manganese phosphate cathode active materials have higher safety and cycle life.
  • the disadvantage of lithium manganese phosphate is poor rate performance. Currently, this is usually solved by coating or doping. One question. However, it is still hoped that the rate performance, cycle performance, high temperature stability, etc. of lithium manganese phosphate cathode active materials can be further improved.
  • This application was made in view of the above problems, and its purpose is to provide a secondary battery, a battery module, a battery pack and a power device to solve the problems of poor rate performance and cycle performance of lithium manganese phosphate secondary batteries.
  • the first aspect of the present application provides a secondary battery, including a positive electrode sheet and a non-aqueous electrolyte, wherein the positive electrode sheet includes a positive electrode active material, and the positive electrode active material has the chemical formula Li a A x Mn 1 -y B y P 1-z C z O 4-n D n , where A includes one or more elements selected from the group consisting of Zn, Al, Na, K, Mg, Nb, Mo and W, B includes one or more elements selected from the group consisting of Ti, V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge, and C includes one or more elements selected from the group consisting of B (boron), S, One or more elements from the group consisting of Si and N, D includes one or more elements selected from the group consisting of S, F, Cl and Br, a is selected from the range of 0.9 to 1.1, x is selected from The range of 0.001 to 0.1, y
  • the non-aqueous electrolyte includes a first lithium salt and a first additive.
  • the first lithium salt is selected from LiN(C m F 2m+1 SO 2 )(C n F 2n+1 SO 2 ), Li(FSO 2 ) 2
  • One or more of the group consisting of N, m and n represent positive integers;
  • the first additive includes one or more compounds represented by Formula 1,
  • R 1 represents a C2-C10 alkylene group, C2-C10 heteroalkylene group, C6-C18 arylene group, C2-C18 heteroarylene group, C3-C18 ester substituted or unsubstituted by one or more R a Any one of cyclic groups and C3 ⁇ C18 heteroalikylidene cyclic groups,
  • R a includes selected from halogen atom, -CN, -NCO, -OH, -COOH, -SOOH, -COOR b , C2 ⁇ C10 alkyl group, C2 ⁇ C10 alkenyl group, C2 ⁇ C10 alkynyl group, C2 ⁇ C10 oxa
  • R b is selected from any one of C1-C10 alkyl groups.
  • the above-mentioned limitation on the numerical range of x is not only a limitation on the stoichiometric number of each element as A, but also on the Limitation of the sum of stoichiometric numbers.
  • A is two or more elements A1, A2...An
  • the respective stoichiometric numbers x1, x2...xn of A1, A2...An must fall within the numerical range of x defined in this application, and x1
  • the sum of , x2...xn also needs to fall within this numerical range.
  • B, C and D are two or more elements
  • the limitations on the numerical ranges of the stoichiometric numbers of B, C and D in this application also have the above meaning.
  • the cathode active material of the present application is obtained by element doping in the compound LiMnPO 4 , where A, B, C and D are elements doped at the Li site, Mn site, P site and O site of the compound LiMnPO 4 respectively.
  • the performance improvement of lithium manganese phosphate is related to reducing the lattice change rate of lithium manganese phosphate and reducing surface activity during the process of deintercalating lithium. Reducing the lattice change rate can reduce the lattice constant difference between the two phases at the grain boundary, reduce the interface stress, and enhance the transport capability of Li + at the interface, thereby improving the rate performance of the cathode active material.
  • the lattice change rate is reduced by Li and Mn site doping.
  • Mn site doping also effectively reduces surface activity, thereby inhibiting the dissolution of manganese ions and the interface side reactions between the cathode active material and the electrolyte.
  • P-site doping makes the Mn-O bond length change faster and reduces the material's small polaron migration barrier, thereby benefiting the electronic conductivity.
  • O-site doping has a good effect on reducing interface side reactions. The doping of P and O sites also affects the dissolution of manganese ions and kinetic properties of anti-site defects.
  • doping reduces the concentration of anti-site defects in the material, improves the dynamic properties and gram capacity of the material, and can also change the morphology of the particles, thereby increasing the compaction density.
  • the applicant unexpectedly discovered that by doping the Li site, Mn site, P site and O site of the compound LiMnPO 4 with specific elements in the specific amount of the present application at the same time, significantly improved rate performance can be obtained while significantly reducing Mn. With the dissolution of Mn-site doping elements, significantly improved cycle performance and/or high-temperature stability are obtained, and the gram capacity and compacted density of the material can also be improved.
  • the non-aqueous electrolyte uses the first lithium salt as the main lithium salt. Due to its excellent thermal stability and hydrolysis resistance, it can effectively reduce the acidity of the electrolyte, reduce the dissolution of manganese ions, and improve high-temperature cycle and storage performance; non-aqueous electrolyte
  • the introduction of the isocyanate-based compound shown in Formula 1 into the electrolyte can react with trace amounts of water in the battery to generate -NHCOOH, preventing trace amounts of water from interacting with the non-aqueous electrolyte to produce HF, further reducing the acidity of the electrolyte and reducing the dissolution of manganese ions. , thereby improving high temperature cycling and storage performance.
  • the isocyanate-based compound shown in Formula 1 can also form a uniform SEI film on the negative electrode, reduce the reduction of dissolved Mn on the negative electrode, and further improve high-temperature cycle and storage performance.
  • R 1 represents a C2 to C10 alkylene group, C2 to C10 oxaalkylene group, C2 to C10 azaalkylene group, or phenylene group substituted or unsubstituted by one or more R a , any one of naphthylene, anthracenylene, cyclobutylene, cyclopentylene, cyclohexylene, biphenylene, and methylene diphenylene, optionally R 1 represents one or Multiple R a substituted or unsubstituted C2-C6 alkylene, phenylene, naphthylene, anthracene, cyclobutylene, cyclopentylene, cyclohexylene, biphenylene, methylene Any one of the diphenylene groups; and/or R a includes one or more selected from halogen atoms, -CN, C2 ⁇ C3 alkyl groups; and/or the individual R a in the compound represented by
  • the above-mentioned first additive includes one or more of the following compounds:
  • LiN(C m F 2m+1 SO 2 )(C n F 2n+1 SO 2 ) in the above-mentioned first lithium salt can be selected from any corresponding specific substances in the prior art.
  • m, n each independently represents 1, 2 or 3 to provide more excellent thermal stability.
  • the first lithium salt is selected from any one of LiN(CF 3 SO 2 ) 2 and Li(FSO 2 ) 2 N
  • the first additive is selected from any one of the following compounds :
  • the content of the first lithium salt is W1% by weight, and W1 is 0.1 to 48 (such as 0.1, 0.5, 1, 2, 3, 4, 5, 7 , 10, 12, 14, 15, 16, 18, 20, 22, 25, 28, 30, 40, 45 or 48), optionally 5 to 20. It alleviates the aluminum foil corrosion problem caused by the first lithium salt under high operating voltage.
  • the content of the first additive is W2% by weight, and W2 is 0.01 to 20 (such as 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 8, 10, 12, 15, 18 or 20), optionally 0.1 to 10 or 0.3 to 5.
  • W2 is 0.01 to 20 (such as 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 8, 10, 12, 15, 18 or 20), optionally 0.1 to 10 or 0.3 to 5.
  • W2 is 0.01 to 20 (such as 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 8, 10, 12, 15, 18 or 20), optionally 0.1 to 10 or 0.3 to 5.
  • the above W2/W1 is defined as M, and M is 0.001 to 3 (such as 0.001, 0.002, 0.005, 0.007, 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2 or 3), optionally is 0.005 to 0.5.
  • W2/W1 is in the above range, the two can play a better synergistic effect to ensure that the acidity of the system is low, the dissolution of manganese ions is reduced, and the high-temperature cycle and storage performance of lithium ions are excellent.
  • the lithium salt in the non-aqueous electrolyte can be supplemented by adding a second lithium salt, that is, the non-aqueous electrolyte also includes a second lithium salt, and the second lithium salt includes Selected from one or more of lithium difluorophosphate, lithium difluorodioxalate phosphate, lithium difluoroxaloborate, lithium bisoxaloborate, LiPF 6 , and LiBF 4 .
  • the second lithium salt is added as a lithium salt-type additive to the non-aqueous electrolyte, it will decompose preferentially on the surface of the aluminum foil.
  • the decomposition products combine with aluminum ions to form an insoluble or insoluble precipitate that adheres to the surface of the aluminum foil, thereby forming a layer of The passivation film prevents direct contact between the aluminum foil and the electrolyte, protects the aluminum foil, and cooperates with the first lithium salt to improve high-temperature cycle and storage performance.
  • the content of the second lithium salt is W3% by weight based on the total weight of the non-aqueous electrolyte, and W3 is 0.01 to 20 (such as 0.01, 0.02, 0.05, 0.08, 0.1, 0.2, 0.3, 0.5, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20), optionally 0.1 to 10 or 0.3 to 5.
  • W3 is 0.01 to 20 (such as 0.01, 0.02, 0.05, 0.08, 0.1, 0.2, 0.3, 0.5, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20), optionally 0.1 to 10 or 0.3 to 5.
  • (W2+W3)/W1 is defined as N, and N is 0.01 to 5 (such as 0.01, 0.02, 0.05, 0.08, 0.1, 0.5, 0.8, 1.0, 2, 3, 4 or 5), Optionally 0.02 to 1.
  • W2/W1 and (W2+W3)/W1 are in the above range, the three can play a better synergistic effect to ensure that the acidity of the system is low, the dissolution of manganese ions is reduced, and the high-temperature cycling and storage performance of lithium ions are excellent; at the same time, it is effective Inhibit aluminum foil corrosion and improve the high-temperature cycle and storage performance of lithium-ion batteries without deteriorating the capacity and rate performance of lithium-ion batteries.
  • the above-mentioned non-aqueous electrolyte further includes a second additive.
  • the second additive includes a cyclic carbonate compound containing an unsaturated bond, a halogen-substituted saturated cyclic carbonate compound, a sulfate compound, and a sulfite compound. , one or more of the group consisting of sultone compounds, disulfonic acid compounds, nitrile compounds, aromatic compounds, phosphazene compounds, cyclic anhydride compounds, phosphite compounds, phosphate ester compounds, and borate ester compounds .
  • Those skilled in the art can select the corresponding second additive from the above substances according to actual needs, and the dosage of the second additive in the non-aqueous electrolyte can also be based on the existing technology, which will not be described again in this application.
  • the above-mentioned non-aqueous electrolyte also includes an organic solvent.
  • the type of organic solvent is not particularly limited and can be selected according to actual needs.
  • the organic solvent includes cyclic carbonate compounds, chain carbonate compounds, One or more carboxylic acid ester compounds, optionally, organic solvents include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, carbonic acid Vinyl ester, propylene carbonate, butylene carbonate, gamma-butyrolactone, methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propionic acid One or more of the group consisting of butyl ester and tetrahydrofuran.
  • A, C, and D of the cathode active material are each independently any one element within the above respective ranges, and the B is at least two elements.
  • A is any element selected from Mg and Nb, and/or,
  • B is at least two elements selected from Fe, Ti, V, Co and Mg, optionally Fe and more than one element selected from Ti, V, Co and Mg, and/or,
  • C is S, and/or
  • the lattice change rate during the delithiation process can be further reduced, thereby further improving the rate performance of the battery.
  • the Mn doping element within the above range the electronic conductivity can be further improved and the lattice change rate can be further reduced, thereby improving the rate performance and gram capacity of the battery.
  • the P-site doping elements within the above range the rate performance of the battery can be further improved.
  • interface side reactions can be further reduced and the high-temperature performance of the battery can be improved.
  • x is selected from the range of 0.001 to 0.005 (such as x is 0.001, 0.002, 0.003, 0.004 or 0.005); and/or y is selected from the range of 0.01 to 0.5 (such as y is 0.01, 0.02, 0.03 , 0.04, 0.05, 0.1, 0.2, 0.25, 0.30, 0.35, 0.40, 0.45 or 0.50), optionally selected from the range of 0.25 to 0.5; and/or, z is selected from the range of 0.001 to 0.005 (for example, z is 0.001 , 0.002, 0.003, 0.004 or 0.005); and/or, n is selected from the range of 0.001 to 0.005 (for example, n is 0.001, 0.002, 0.003, 0.004 or 0.005).
  • the gram capacity and rate performance of the material can be further improved.
  • the x value within the above range the dynamic properties of the material can be further improved.
  • the z value within the above range the rate performance of the secondary battery can be further improved.
  • the n value within the above range the high-temperature performance of the secondary battery can be further improved.
  • the cathode active material satisfies: (1-y): y is in the range of 1 to 4, optionally in the range of 1.5 to 3, and a:x is in the range of 9 to 1100, optionally in Within the range of 190-998.
  • y represents the sum of stoichiometric numbers of Mn-site doping elements.
  • the cathode active material has a lattice change rate of 8% or less, optionally, a lattice change rate of 4% or less.
  • a lattice change rate can be measured by methods known in the art, such as X-ray diffraction (XRD).
  • the positive electrode active material has a Li/Mn anti-site defect concentration of 2% or less, and optionally, the Li/Mn anti-site defect concentration is 0.5% or less.
  • the so-called Li/Mn antisite defect refers to the interchange of positions between Li + and Mn 2+ in the LiMnPO 4 lattice.
  • the Li/Mn anti-site defect concentration refers to the percentage of Li + exchanged with Mn 2+ in the positive active material to the total amount of Li + . Mn 2+ with anti-site defects will hinder the transport of Li + .
  • the Li/Mn anti-site defect concentration can be measured by methods known in the art, such as XRD.
  • the surface oxygen valence state of the cathode active material is -1.82 or less, optionally -1.89 to -1.98.
  • the interface side reaction between the positive electrode active material and the electrolyte can be reduced, thereby improving the cycle performance and high temperature stability of the secondary battery.
  • Surface oxygen valence state can be measured by methods known in the art, such as by electron energy loss spectroscopy (EELS).
  • the positive active material has a compacted density of 2.0 g/cm or more at 3 T (tons), optionally 2.2 g/cm or more.
  • the compacted density can be measured according to GB/T24533-2009.
  • the cathode active material is surface-coated with carbon. Thereby, the conductivity of the positive electrode active material can be improved.
  • a second aspect of the present application also provides a battery module.
  • the battery module includes a secondary battery, and the secondary battery is any of the above-mentioned secondary batteries of the present application.
  • a third aspect of the present application also provides a battery pack, which includes a battery module, and the battery module is the above-mentioned battery module of the present application.
  • a fourth aspect of the present application also provides an electrical device, which includes at least one of a secondary battery, a battery module, or a battery pack.
  • a secondary battery which includes at least one of a secondary battery, a battery module, or a battery pack.
  • the above secondary batteries, battery modules, and battery packs are all provided by the present application. Secondary batteries, battery modules, and battery packs.
  • the battery module and battery pack of the present application have higher cycle performance and rate characteristics, and especially the high temperature stability is significantly improved, thereby providing power consumption devices with the secondary battery, battery module or battery pack of the present application.
  • High power cycle stability and high temperature operating stability are particularly preferred.
  • FIG. 1 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 2 is an exploded view of the secondary battery according to the embodiment of the present application shown in FIG. 1 .
  • FIG. 3 is a schematic diagram of a battery module according to an embodiment of the present application.
  • Figure 4 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 5 is an exploded view of the battery pack according to an embodiment of the present application shown in FIG. 4 .
  • FIG. 6 is a schematic diagram of a power consumption device using a secondary battery as a power source according to an embodiment of the present application.
  • Ranges disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit that define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive of the endpoints, and may be arbitrarily combined, that is, any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, understand that ranges of 60-110 and 80-120 are also expected. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • the numerical range “a-b” represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers.
  • the numerical range “0-5" means that all real numbers between "0-5" have been listed in this article, and "0-5" is just an abbreviation of these numerical combinations.
  • a certain parameter is an integer ⁇ 2
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • step (c) means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c). , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b), etc.
  • condition "A or B” is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; Or both A and B are true (or exist).
  • Secondary batteries also known as rechargeable batteries or storage batteries, refer to batteries that can be recharged to activate active materials and continue to be used after the battery is discharged.
  • a secondary battery normally includes a positive electrode plate, a negative electrode plate, a separator and an electrolyte.
  • active ions such as lithium ions
  • the isolation film is placed between the positive electrode piece and the negative electrode piece. It mainly prevents the positive and negative electrodes from short-circuiting and allows active ions to pass through.
  • the electrolyte is between the positive electrode piece and the negative electrode piece and mainly plays the role of conducting active ions.
  • One embodiment of the present application provides a secondary battery, including a positive electrode sheet and a non-aqueous electrolyte, wherein the positive electrode sheet includes a positive electrode active material, and the positive electrode active material has a chemical formula Li a A x Mn 1-y By P 1 -z C z O 4-n D n , where A includes one or more elements selected from the group consisting of Zn, Al, Na, K, Mg, Nb, Mo and W, and B includes Ti, One or more elements from the group consisting of V, Zr, Fe, Ni, Mg, Co, Ga, Sn, Sb, Nb and Ge, C includes selected from the group consisting of B (boron), S, Si and N
  • One or more elements in, D includes one or more elements selected from the group consisting of S, F, Cl and Br, a is selected from the range of 0.9 to 1.1, x is selected from the range of 0.001 to 0.1, y is selected from the range of 0.001 to 0.5, z is selected
  • the non-aqueous electrolyte solution includes a first lithium salt and a first additive.
  • the first lithium salt includes LiN(C m F 2m+1 SO 2 )(C n F 2n+1 SO 2 ), Li(FSO 2 )
  • the group consisting of 2 N, m and n represent positive integers;
  • the first additive includes one or more compounds represented by Formula 1,
  • R 1 represents a C2-C10 alkylene group, C2-C10 heteroalkylene group, C6-C18 arylene group, C2-C18 heteroarylene group, C3-C18 ester substituted or unsubstituted by one or more R a Any one of cyclic groups and C3 ⁇ C18 heteroalikylidene cyclic groups,
  • R a includes selected from halogen atom, -CN, -NCO, -OH, -COOH, -SOOH, -COOR b , C2 ⁇ C10 alkyl group, C2 ⁇ C10 alkenyl group, C2 ⁇ C10 alkynyl group, C2 ⁇ C10 oxa
  • R b is selected from any one of C1-C10 alkyl groups.
  • the positive electrode sheet usually includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector.
  • the positive electrode film layer includes a positive electrode active material.
  • the positive electrode current collector has two surfaces facing each other in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • the metal foil aluminum foil can be used.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the cathode active material of the present application is obtained by element doping in the compound LiMnPO 4 , where A, B, C and D are elements doped at the Li site, Mn site, P site and O site of the compound LiMnPO 4 respectively.
  • the performance improvement of lithium manganese phosphate is related to reducing the lattice change rate of lithium manganese phosphate and reducing surface activity during the process of deintercalating lithium. Reducing the lattice change rate can reduce the lattice constant difference between the two phases at the grain boundary, reduce the interface stress, and enhance the transport capability of Li + at the interface, thereby improving the rate performance of the cathode active material.
  • the lattice change rate is reduced by Li and Mn site doping.
  • Mn site doping also effectively reduces surface activity, thereby inhibiting the dissolution of manganese ions and the interface side reactions between the cathode active material and the electrolyte.
  • P-site doping makes the Mn-O bond length change faster and reduces the material's small polaron migration barrier, thereby benefiting the electronic conductivity.
  • O-site doping has a good effect on reducing interface side reactions. The doping of P and O sites also affects the dissolution of manganese ions and kinetic properties of anti-site defects.
  • doping reduces the concentration of anti-site defects in the material, improves the dynamic properties and gram capacity of the material, and can also change the morphology of the particles, thereby increasing the compaction density.
  • the applicant unexpectedly discovered that by doping the Li site, Mn site, P site and O site of the compound LiMnPO 4 with specific elements in the specific amount of the present application at the same time, significantly improved rate performance can be obtained while significantly reducing Mn. With the dissolution of Mn-site doping elements, significantly improved cycle performance and/or high-temperature stability are obtained, and the gram capacity and compacted density of the material can also be improved.
  • the non-aqueous electrolyte uses the first lithium salt as the main lithium salt. Due to its excellent thermal stability and hydrolysis resistance, it can effectively reduce the acidity of the electrolyte, reduce the dissolution of manganese ions, and improve high-temperature cycle and storage performance; non-aqueous electrolyte
  • the introduction of the isocyanate-based compound shown in Formula 1 into the electrolyte can react with trace amounts of water in the battery to generate -NHCOOH, preventing trace amounts of water from interacting with the non-aqueous electrolyte to produce HF, further reducing the acidity of the electrolyte and reducing the dissolution of manganese ions. , thereby improving high temperature cycling and storage performance.
  • the isocyanate-based compound shown in Formula 1 can also form a uniform SEI film on the negative electrode, reduce the reduction of dissolved Mn on the negative electrode, and further improve high-temperature cycle and storage performance.
  • the non-aqueous electrolyte solution includes a first lithium salt and a first additive, and the first lithium salt is present as the main lithium salt.
  • LiN(C m F 2m+1 SO 2 )(C n F 2n+1 SO 2 ) in the above-mentioned first lithium salt can be selected from any corresponding specific substances in the prior art.
  • m, n each independently represents 1, 2 or 3 to provide more excellent thermal stability.
  • the first lithium salt is selected from any one or more of the group consisting of LiN(C m F 2m+1 SO 2 )(C n F 2n+1 SO 2 ) and Li(FSO 2 ) 2 N, such as It can be used in (fluorosulfonimide)(trifluoromethanesulfonimide)lithium Li(FSO 2 )(CF 3 SO 2 )N, bis(trifluoromethanesulfonimide) lithium (LiN(CF 3 SO 2 ) 2 ), bis(pentafluoroethanesulfonimide) lithium (LiN(C 2 F 5 SO 2 ) 2 ), (trifluoromethanesulfonimide) (pentafluoroethanesulfonimide) lithium (LiN( CF 3 SO 2 )(C 2 F 5 SO 2 )), (trifluoromethanesulfonimide) (pentafluoroethanesulfonimide) lithium
  • the isocyanate compound shown in 1 used in this application can be selected from the isocyanate compounds commonly used in electrolytes in the prior art.
  • the above R 1 represents C2 substituted or unsubstituted by one or more R a ⁇ C10 alkylene, C2 ⁇ C10 oxalkylene, C2 ⁇ C10 azaalkylene, phenylene, naphthylene, anthracenylene, cyclobutylene, cyclopentylene, cyclohexylene, Any one of biphenylene and methylene diphenylene, optionally R 1 represents a C2-C6 alkylene, phenylene or naphthylene group substituted or unsubstituted by one or more R a , any one of anthracenylene, cyclobutylene, cyclopentylene, cyclohexylene, biphenylene, and methylene diphenylene; and/or R a includes a halogen atom,
  • Each of the above compounds has good dispersion and solubility properties in the solvent of the non-aqueous electrolyte, and can fully react with trace amounts of water in the battery - NHCOOH, preventing trace amounts of water from interacting with the non-aqueous electrolyte to produce HF, further reducing the acidity and Reduce the dissolution of manganese ions, thereby improving high temperature cycle and storage performance.
  • the above-mentioned isocyanate-based compounds are more likely to form a uniform SEI film on the negative electrode, which is more conducive to reducing the reduction of dissolved Mn at the negative electrode, further improving high-temperature cycle and storage performance.
  • the first lithium salt is selected from any one of LiN(CF 3 SO 2 ) 2 and Li(FSO 2 ) 2 N
  • the first additive is selected from any one of the following compounds :
  • first lithium salt as the main lithium salt of the non-aqueous electrolyte can effectively improve the high-temperature cycle and storage performance of the secondary battery, this substance will corrode the lithium salt under certain conditions, such as when the working voltage of the lithium-ion battery When >4.2V, there will be a problem of aluminum foil corrosion.
  • the possible mechanism is that after the original oxide film on the surface of the aluminum foil is destroyed in the electrolyte, more active aluminum is exposed, and then the aluminum is oxidized to produce Al 3+ ions. Then FSI- or TFSI- and Al 3+ in the electrolyte combine to form soluble Al(FSI) 3 or Al(TFSI) 3.
  • the content of the first lithium salt is W1 wt%, and W1 is 0.1 to 48, which can be Choose locations from 5 to 20.
  • the lithium salt in the non-aqueous electrolyte can be supplemented by adding a second lithium salt, that is, the non-aqueous electrolyte also includes a second lithium salt, and the second lithium salt includes Selected from one or more of lithium difluorophosphate, lithium difluorodioxalate phosphate, lithium difluoroxaloborate, lithium bisoxaloborate, LiPF 6 , and LiBF 4 .
  • the second lithium salt is added as a lithium salt-type additive to the non-aqueous electrolyte, it will decompose preferentially on the surface of the aluminum foil.
  • the decomposition products combine with aluminum ions to form an insoluble or insoluble precipitate that adheres to the surface of the aluminum foil, thereby forming a layer of The passivation film prevents direct contact between the aluminum foil and the electrolyte, protects the aluminum foil, and cooperates with the first lithium salt to improve high-temperature cycle and storage performance.
  • the content of the second lithium salt is W3% by weight based on the total weight of the non-aqueous electrolyte, and W3 is 0.01 to 20, optionally 0.1 to 10 or 0.3 to 5.
  • W3 is 0.01 to 20, optionally 0.1 to 10 or 0.3 to 5.
  • the first additive can form a uniform SEI film on the negative electrode, it can reduce the reduction of dissolved Mn in the negative electrode, further improving high-temperature cycle and storage performance. However, too much isocyanate-based compounds will increase the resistance of the negative electrode, causing abnormal capacity and poor rate performance of lithium-ion batteries.
  • the content of the first additive is W2% by weight, and W2 is 0.01 to 20, optionally 0.1 to 10 or 0.3 to 5.
  • both It can reduce the acidity of the electrolyte, reduce the dissolution of manganese ions, and avoid deterioration of the negative electrode impedance, thus improving the high-temperature cycle and storage performance of lithium-ion batteries without affecting the capacity and rate performance of lithium-ion batteries.
  • W2/W1 is defined as M, and M is 0.001 to 3, optionally 0.005 to 0.5.
  • (W2+W3)/W1 is defined as N, where N is 0.01 to 2, optionally 0.02 to 1.
  • the above-mentioned non-aqueous electrolyte further includes a second additive.
  • the second additive includes a cyclic carbonate compound containing an unsaturated bond, a halogen-substituted saturated cyclic carbonate compound, a sulfate compound, and a sulfite compound. , one or more of the group consisting of sultone compounds, disulfonic acid compounds, nitrile compounds, aromatic compounds, phosphazene compounds, cyclic anhydride compounds, phosphite compounds, phosphate ester compounds, and borate ester compounds .
  • Those skilled in the art can select the corresponding second additive from the above substances according to actual needs, and the dosage of the second additive in the non-aqueous electrolyte can also be based on the existing technology, which will not be described again in this application.
  • the above-mentioned non-aqueous electrolyte also includes an organic solvent.
  • the type of organic solvent is not particularly limited and can be selected according to actual needs.
  • the organic solvent includes cyclic carbonate compounds, chain carbonate compounds, One or more carboxylic acid ester compounds, optionally, organic solvents include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, carbonic acid Vinyl ester, propylene carbonate, butylene carbonate, gamma-butyrolactone, methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propionic acid One or more of the group consisting of butyl ester and tetrahydrofuran.
  • A, C, and D of the cathode active material are each independently any one element within the above respective ranges, and the B is at least two elements.
  • A is any element selected from Mg and Nb, and/or,
  • B is at least two elements selected from Fe, Ti, V, Co and Mg, optionally Fe and more than one element selected from Ti, V, Co and Mg, and/or,
  • C is S, and/or
  • the lattice change rate during the delithiation process can be further reduced, thereby further improving the rate performance of the battery.
  • the Mn doping element within the above range the electronic conductivity can be further improved and the lattice change rate can be further reduced, thereby improving the rate performance and gram capacity of the battery.
  • the P-site doping elements within the above range the rate performance of the battery can be further improved.
  • interface side reactions can be further reduced and the high-temperature performance of the battery can be improved.
  • x is selected from the range of 0.001 to 0.005; and/or, y is selected from the range of 0.01 to 0.5, optionally selected from the range of 0.25 to 0.5; and/or, z is selected from the range of 0.001 to 0.005 range; and/or, n is selected from the range of 0.001 to 0.005.
  • y value within the above range
  • the gram capacity and rate performance of the material can be further improved.
  • the x value within the above range the dynamic properties of the material can be further improved.
  • the z value within the above range the rate performance of the secondary battery can be further improved.
  • the n value within the above range the high-temperature performance of the secondary battery can be further improved.
  • the cathode active material satisfies: (1-y): y is in the range of 1 to 4, optionally in the range of 1.5 to 3, and a:x is in the range of 9 to 1100, optionally in Within the range of 190-998.
  • y represents the sum of stoichiometric numbers of Mn-site doping elements.
  • the cathode active material has a lattice change rate of 8% or less, optionally, a lattice change rate of 4% or less.
  • a lattice change rate can be measured by methods known in the art, such as X-ray diffraction (XRD).
  • the positive electrode active material has a Li/Mn anti-site defect concentration of 2% or less, and optionally, the Li/Mn anti-site defect concentration is 0.5% or less.
  • the so-called Li/Mn antisite defect refers to the interchange of positions between Li + and Mn 2+ in the LiMnPO4 lattice.
  • the Li/Mn anti-site defect concentration refers to the percentage of Li + exchanged with Mn 2+ in the positive active material to the total amount of Li + . Mn 2+ with anti-site defects will hinder the transport of Li + .
  • the Li/Mn anti-site defect concentration can be measured by methods known in the art, such as XRD.
  • the surface oxygen valence state of the cathode active material is -1.82 or less, optionally -1.89 to -1.98.
  • the interface side reaction between the positive electrode active material and the electrolyte can be reduced, thereby improving the cycle performance and high temperature stability of the secondary battery.
  • Surface oxygen valence state can be measured by methods known in the art, such as by electron energy loss spectroscopy (EELS).
  • the positive active material has a compacted density of 2.0 g/cm or more at 3 T (tons), optionally 2.2 g/cm or more.
  • the compacted density can be measured according to GB/T24533-2009.
  • the cathode active material is surface-coated with carbon. Thereby, the conductivity of the positive electrode active material can be improved.
  • the preparation method of the cathode active material of the present application is described below, but the following description is only an exemplary description, and those skilled in the art can use other feasible methods to prepare the cathode active material of the present application.
  • the preparation method of the cathode active material includes: Step (1): Dissolve a manganese source, a source of element B and an acid in a solvent and stir to generate a suspension of a manganese salt doped with element B, and The suspension is filtered and the filter cake is dried to obtain a manganese salt doped with element B; step (2): combine a lithium source, a phosphorus source, a source of element A, a source of element C and a source of element D, a solvent and The manganese salt doped with element B obtained in step (1) is added to the reaction vessel, ground and mixed to obtain a slurry; step (3): transfer the slurry obtained in step (2) to a spray drying equipment for spray drying. particles to obtain particles; step (4): sintering the particles obtained in step (3) to obtain the above-mentioned positive electrode active material.
  • the stirring in the above step (1) is performed at a temperature in the range of 60-120°C, and/or the stirring in step (1) is performed at a stirring rate of 200-800 rpm.
  • the grinding and mixing of the above step (2) is performed for 8-15 hours.
  • the sintering in step (4) above is performed in a temperature range of 600-900°C for 6-14 hours.
  • the source of element A is selected from at least one of element A, oxide, phosphate, oxalate, carbonate and sulfate
  • the source of element B is selected from element B, oxidation at least one of phosphate, oxalate, carbonate and sulfate
  • the source of element C is selected from at least one of sulfate, borate, nitrate and silicate of element C
  • the element The source of D is selected from at least one of elemental elements and ammonium salts of element D.
  • the positive electrode film layer may also include other positive electrode active materials known in the art for secondary batteries.
  • the cathode active material may include at least one of the following materials: an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for secondary batteries can also be used. Only one type of these positive electrode active materials may be used alone, or two or more types may be used in combination.
  • lithium transition metal oxides may include, but are not limited to, lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 , LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide , at least one of lithium nickel manganese oxide and its modified compounds.
  • lithium-containing phosphates with an olivine structure may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), composites of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), phosphoric acid At least one of a composite material of lithium manganese and carbon, a composite material of lithium manganese iron phosphate, or a composite material of lithium manganese iron phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also referred to as LFP)
  • composites of lithium iron phosphate and carbon such as LiMnPO 4
  • LiMnPO 4 lithium manganese phosphate
  • phosphoric acid At least one of a composite material of lithium manganese and carbon, a composite material of lithium manganese iron phosphate, or a composite material of lithium manganese iron phosphate and carbon.
  • the positive electrode film layer optionally further includes a binder.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene tripolymer. At least one of a meta-copolymer, a tetrafluoroethylene-hexafluoropropylene copolymer and a fluorine-containing acrylate resin.
  • the positive electrode film layer optionally further includes a conductive agent.
  • the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
  • the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components in a solvent (such as N -methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode piece can be obtained.
  • a solvent such as N -methylpyrrolidone
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, where the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two opposite surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base material.
  • the composite current collector can be formed by forming metal materials (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative active material may be a negative active material known in the art for batteries.
  • the negative active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and the like.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon carbon composites, silicon nitrogen composites and silicon alloys.
  • the tin-based material may be selected from at least one of elemental tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other traditional materials that can be used as battery negative electrode active materials can also be used. Only one type of these negative electrode active materials may be used alone, or two or more types may be used in combination.
  • the negative electrode film layer optionally further includes a binder.
  • the binder may be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), At least one of polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer optionally further includes a conductive agent.
  • the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer optionally includes other auxiliaries, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative active materials, conductive agents, binders and any other components in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode piece can be obtained.
  • a solvent such as deionized water
  • the secondary battery further includes a separator film.
  • a separator film There is no particular restriction on the type of isolation membrane in this application. Any well-known porous structure isolation membrane with good chemical stability and mechanical stability can be used.
  • the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the isolation film can be a single-layer film or a multi-layer composite film, with no special restrictions. When the isolation film is a multi-layer composite film, the materials of each layer can be the same or different, and there is no particular limitation.
  • the positive electrode piece, the negative electrode piece and the separator film can be made into an electrode assembly through a winding process or a lamination process.
  • the secondary battery may include an outer packaging.
  • the outer packaging can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the secondary battery may also be a soft bag, such as a bag-type soft bag.
  • the material of the soft bag may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 1 shows a square-structured secondary battery 5 as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose a receiving cavity.
  • the housing 51 has an opening communicating with the accommodation cavity, and the cover plate 53 can cover the opening to close the accommodation cavity.
  • the positive electrode piece, the negative electrode piece and the isolation film can be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the containing cavity.
  • the electrolyte soaks into the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.
  • secondary batteries can be assembled into battery modules, and the number of secondary batteries contained in the battery module can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery module.
  • FIG. 3 is a battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4 .
  • the plurality of secondary batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having a receiving space in which a plurality of secondary batteries 5 are received.
  • the above-mentioned battery modules can also be assembled into a battery pack.
  • the number of battery modules contained in the battery pack can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box 2 and a lower box 3 .
  • the upper box 2 can be covered with the lower box 3 and form a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided by the present application.
  • the secondary battery, battery module, or battery pack may be used as a power source for the electrical device, or may be used as an energy storage unit for the electrical device.
  • the electric device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, and electric golf carts). , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited to these.
  • a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.
  • FIG. 6 is an electrical device as an example.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc.
  • a battery pack or battery module can be used.
  • the first additive is selected from the following compounds:
  • Preparation of doped manganese oxalate add 1.3 mol of MnSO 4 . H 2 O, 0.7mol FeSO 4 . The H 2 O was mixed thoroughly in the mixer for 6 hours. The mixture was transferred to the reaction kettle, and 10 L of deionized water and 2 mol of oxalic acid dihydrate (calculated as oxalic acid) were added. The reaction kettle was heated to 80° C. and stirred at a rotation speed of 600 rpm for 6 hours. The reaction was terminated (no bubbles were generated), and an Fe-doped manganese oxalate suspension was obtained. The suspension is then filtered, and the filter cake is dried at 120° C. and then ground to obtain Fe-doped manganese oxalate particles with a median particle size Dv 50 of about 100 nm.
  • Preparation of doped lithium manganese phosphate Take 1 mol of the above manganese oxalate particles, 0.497 mol of lithium carbonate, 0.001 mol of Mo(SO 4 ) 3 , an 85% phosphoric acid aqueous solution containing 0.999 mol of phosphoric acid, and 0.001 mol of H 4 SiO 4 , 0.0005mol NH 4 HF 2 and 0.005mol sucrose were added to 20L deionized water. The mixture was transferred to a sand mill and thoroughly ground and stirred for 10 hours to obtain a slurry. Transfer the slurry to spray drying equipment for spray drying and granulation. Set the drying temperature to 250°C and dry for 4 hours to obtain granules.
  • the above powder was sintered at 700°C for 10 hours to obtain carbon-coated Li 0.994 Mo 0.001 Mn 0.65 Fe 0.35 P 0.999 Si 0.001 O 3.999 F 0.001 .
  • the element content of the cathode active material can be detected by inductively coupled plasma emission spectroscopy (ICP).
  • the above-mentioned positive electrode active material, polyvinylidene fluoride (PVDF), and acetylene black were added to N-methylpyrrolidone (NMP) in a weight ratio of 90:5:5, and stirred in a drying room to form a slurry.
  • NMP N-methylpyrrolidone
  • the above slurry is coated on aluminum foil, dried and cold pressed to form a positive electrode sheet.
  • the coating amount is 0.2g/cm 2 and the compacted density is 2.0g/cm 3 .
  • a lithium sheet is used as the negative electrode, and Li(FSO 2 ) 2 N (the first lithium salt, the mass content in the electrolyte is 15%), and Compound 1 (the first additive, the mass content in the electrolyte is 1%) , LiPF 6 (the second lithium salt, the mass content in the electrolyte is 3%) 1mol/L in a volume ratio of 1:1:1 of ethylene carbonate (EC), diethyl carbonate (DEC) and dimethyl carbonate
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • DMC dimethyl carbonate
  • the solution in ester (DMC) is an electrolyte, in which the total amount of the first lithium salt and the first additive of the positive electrode active material corresponding to the unit area is controlled to 5.4 mg/m 2 , and is placed in the battery box together with the positive electrode sheet prepared above It is assembled into a button battery (hereinafter also referred to as "button battery”).
  • PE polyethylene
  • Preparation of manganese oxalate add 1 mol of MnSO 4 . H 2 O was added to the reaction kettle, and 10 L of deionized water and 1 mol of oxalic acid dihydrate (calculated as oxalic acid) were added. The reaction kettle was heated to 80°C and stirred at 600 rpm for 6 hours. The reaction was terminated (no bubbles were generated), and a manganese oxalate suspension was obtained. The suspension is then filtered, and the filter cake is dried at 120° C. and then ground to obtain manganese oxalate particles with a median particle size Dv 50 of 50-200 nm.
  • Preparation of lithium manganese phosphate Take 1 mol of the above manganese oxalate particles, 0.5 mol of lithium carbonate, an 85% phosphoric acid aqueous solution containing 1 mol of phosphoric acid, and 0.005 mol of sucrose and add them to 20 L of deionized water. The mixture was transferred to a sand mill and thoroughly ground and stirred for 10 hours to obtain a slurry. Transfer the slurry to spray drying equipment for spray drying and granulation. Set the drying temperature to 250°C and dry for 4 hours to obtain granules. In a protective atmosphere of nitrogen (90 volume %) + hydrogen (10 volume %), the above powder was sintered at 700° C. for 10 hours to obtain carbon-coated LiMnPO 4 .
  • the positive active material sample is prepared into a buckle, and the buckle is charged at a small rate of 0.05C until the current is reduced to 0.01C. Then take out the positive electrode piece from the battery and soak it in DMC for 8 hours. Then it is dried, scraped into powder, and particles with a particle size less than 500nm are screened out. Take a sample and calculate its lattice constant v1 in the same way as the above-mentioned test of the fresh sample. (v0-v1)/v0 ⁇ 100% is shown in the table as the lattice change rate before and after complete deintercalation of lithium.
  • the drainage method is to first separately measure the gravity F 1 of the battery cell using a balance that automatically converts units based on the dial data, then completely places the battery core in deionized water (density is known to be 1g/cm 3 ), and measures the battery core at this time.
  • the battery of the embodiment always maintained an SOC of more than 99% during the experiment until the end of storage.
  • the positive electrode active material compositions of Examples 1-11 and Comparative Examples 1-4 are shown in Table 1.
  • Table 2 shows the performance data of the positive electrode active materials of Examples 1-11 and Comparative Examples 1-4 measured with or without electricity according to the above performance testing method.
  • Table 3 shows the positive electrode active material compositions of Examples 12-27.
  • Table 4 shows the performance data of the cathode active materials of Examples 12-27 measured according to the above performance test method with or without electricity.
  • the positive electrode active material, buckle charge and full charge were prepared in the same manner as in Example 18, but the electrolyte composition was changed, as shown in Table 5 below.
  • each cathode active material of the embodiments of the present application achieves better results than the comparative example in one or even all aspects of cycle performance, high temperature stability, gram capacity, and compacted density.
  • (1-y):y is in the range of 1 to 4, which can further improve the energy density of the secondary battery. and cycle performance.
  • the electrolyte in the button cells of the above-mentioned embodiments 1 to 29 was replaced with: using 1 mol/L LiPF 6 in a volume ratio of 1:1:1 of ethylene carbonate (EC), diethyl carbonate (DEC) and The electrolyte consists of a solution in dimethyl carbonate (DMC); replace the electrolyte of the full battery with: 1 mol/L LiPF 6 in a volume ratio of 1:1:1 ethylene carbonate (EC), diethyl carbonate
  • the electrolyte composition of the present application can further improve the energy density and cycle performance of the secondary battery.

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Abstract

二次电池、电池模块、电池包和用电装置。二次电池包括正极极片以及非水电解液，其中，正极极片包括正极活性材料，正极活性材料具有化学式Li aA xMn 1-yB yP 1-zC zO 4-nD n；非水电解液包括第一锂盐和第一添加剂，可选地，第一锂盐选自LiN(C mF 2m+1SO 2)(C nF 2n+1SO 2)、Li(FSO 2) 2N组成的组中的一种或多种，m、n表示正整数；第一添加剂包括式1所示化合物中的一种或多种。利用正极活性材料或正极活性材料和非水电解液的结合提高了磷酸锰锂二次电池的倍率性能、循环性能和高温稳定性。 O＝＝C＝＝N——R 1——N＝＝C＝＝O 式1

Description

二次电池、电池模块、电池包和用电装置 技术领域
本申请涉及锂电池技术领域，尤其涉及一种二次电池、电池模块、电池包和用电装置。
背景技术
近年来，随着锂离子电池的应用范围越来越广泛，锂离子电池广泛应用于水力、火力、风力和太阳能电站等储能电源系统，以及电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。由于锂离子电池取得了极大的发展，因此对其能量密度、循环性能和安全性能等也提出了更高的要求。
与其他正极活性材料相比，磷酸锰锂正极活性材料具有较高的安全性和循环寿命，但是磷酸锰锂的缺点在于倍率性能较差，目前通常是通过包覆或掺杂等手段来解决这一问题。但仍然希望能够进一步提升磷酸锰锂正极活性材料的倍率性能、循环性能、高温稳定性等。
发明内容
本申请是鉴于上述课题而进行的，其目的在于，提供一种二次电池、电池模块、电池包和用电装置，以解决磷酸锰锂二次电池的倍率性能和循环性能差的问题。
为了达到上述目的，本申请的第一方面提供了一种二次电池，包括正极极片以及非水电解液，其中，正极极片包括正极活性材料，正极活性材料具有化学式Li aA xMn 1-yB yP 1-zC zO 4-nD n，其中，A包括选自Zn、Al、Na、K、Mg、Nb、Mo和W组成的组中的一种或多种元素，B包括选自Ti、V、Zr、Fe、Ni、Mg、Co、Ga、Sn、Sb、Nb和Ge组成的组中的一种或多种元素，C包括选自B(硼)、S、Si和N组成的组中的一种或多种元素，D包括选自S、F、Cl和Br组成的组中的一种或多种元素，a选自0.9至1.1的范围，x选自0.001至0.1的范围，y选自0.001至0.5的范围，z选自0.001至0.1的范围，n选自0.001至0.1的范围，并且正极活性材料为电中性的；
非水电解液包括第一锂盐和第一添加剂，可选地，第一锂盐选自LiN(C mF 2m+1SO 2)(C nF 2n+1SO 2)、Li(FSO 2) 2N组成的组中的一种或多种，m、n表示正整数；
第一添加剂包括式1所示化合物中的一种或多种，
Figure PCTCN2022084859-appb-000001
R 1表示经一个或多个R a取代或未取代的C2～C10亚烷基、C2～C10杂亚烷基、C6～C18亚芳基、C2～C18杂亚芳基、C3～C18亚脂环基、C3～C18杂亚脂环基中的任意一种，
R a包括选自卤原子、-CN、-NCO、-OH、-COOH、-SOOH、-COOR b、C2～C10烷基、C2～C10烯基、C2～C10炔基、C2～C10氧杂烷基中的一种或多种，R b选自C1-C10烷基中的任意一种。
除非另有说明，否则上述化学式中，当A为两种以上元素时，上述对于x数值范围的限定不仅是对每种作为A的元素的化学计量数的限定，也是对各个作为A的元素的化学计量数之和的限定。例如当A为两种以上元素A1、A2……An时，A1、A2……An各自的化学计量数x1、x2……xn各自均需落入本申请对x限定的数值范围内，且x1、x2……xn之和也需落入该数值范围内。类似地，对于B、C和D为两种以上元素的情况，本申请中对B、C和D化学计量数的数值范围的限定也具有上述含义。
本申请的正极活性材料通过在化合物LiMnPO 4中进行元素掺杂而获得，其中，A、B、C和D分别为在化合物LiMnPO 4的Li位、Mn位、P位和O位掺杂的元素。不希望囿于理论，现认为磷酸锰锂的性能提升与减小脱嵌锂过程中磷酸锰锂的晶格变化率和降低表面活性有关。减小晶格变化率可减小晶界处两相间的晶格常数差异，减小界面应力，增强Li +在界面处的传输能力，从而提升正极活性材料的倍率性能。而表面活性高容易导致界面副反应严重，加剧产气、电解液消耗和破坏界面，从而影响电池的循环等性能。本申请中，通过Li和Mn位掺杂减小了晶格变化率。Mn位掺杂还有效降低表面活性，从而抑制锰离子溶出和正极活性材料与电解液的界面副反应。P位掺杂使Mn-O键长的变化速率更快，降低材料的小极化子迁移势垒，从而有利于电子电导率。O位掺杂对减小界面副反应有良好的作用。P位和O位的掺杂还对反位缺陷的锰离子溶出及动力学性能产生影响。因此，掺杂减小了材料中反位缺陷浓度，提高材料的动力学性能和克容量，还可以改变颗粒的形貌，从而提升压实密度。本申请人意外地发现：通过在化合物LiMnPO 4的Li位、Mn位、P位和O位同时以本申请的特定量掺杂特定的元素，能够获得明显改善的倍率性能，同时显著减少了Mn与Mn位掺杂元素的溶出，获得了显著改善的循环性能和/或高温稳定性，并且材料的克容量和压实密度也可以得到提高。
同时，非水电解液以第一锂盐为主锂盐，由于其优异的热稳定性和耐水解能力，可以有效降低电解液酸度，减小锰离子溶出，改善高温循环和存储性能；非水电解液中引入式1所示的异氰酸酯基化合物，可与电池中的痕量水反应生成-NHCOOH，防止痕量水与非水电解液作用产生HF，进一步降低电解液酸度和 减小锰离子溶出，进而改善高温循环和存储性能。此外，式1所示的异氰酸酯基化合物还可以在负极成膜生成均匀的SEI膜，减小溶出的Mn在负极还原，进一步改善高温循环和存储性能。
在一些实施方式中，上述R 1表示经一个或多个R a取代或未取代的C2～C10亚烷基、C2～C10氧杂亚烷基、C2～C10氮杂亚烷基、亚苯基、亚萘基、亚蒽基、亚环丁基、亚环戊基、亚环己基、亚联苯基、亚甲基二亚苯基中的任意一种，可选地R 1表示经一个或多个R a取代或未取代的C2～C6亚烷基、亚苯基、亚萘基、亚蒽基、亚环丁基、亚环戊基、亚环己基、亚联苯基、亚甲基二亚苯基中的任意一种；和/或R a包括选自卤原子、-CN、C2～C3烷基中的一种或多种；和/或式1所示化合物中R a的个数为0、1、2、3或4个。
可选地，上述第一添加剂包括如下化合物中的一种或多种：
Figure PCTCN2022084859-appb-000002
Figure PCTCN2022084859-appb-000003
上述第一锂盐中的LiN(C mF 2m+1SO 2)(C nF 2n+1SO 2)可以从现有技术中任意的相应具体物质中选择，在一些实施方式中，m、n各自独立地表示1、2或3，以提供更优异的热稳定性。
在本申请的一些实施方式中，当第一锂盐选自LiN(CF 3SO 2) 2、Li(FSO 2) 2N中的任意一种，第一添加剂选自如下化合物中的任意一种：
Figure PCTCN2022084859-appb-000004
Figure PCTCN2022084859-appb-000005
此时，二者的优势得到充分发挥且电解液酸度和锰离子溶出显著降低，锂离子电池的高温循环和存储性能得到显著改善。
在一些实施方式中，基于非水电解液的总重量，第一锂盐的含量为W1重量％，W1为0.1至48(比如为0.1、0.5、1、、2、3、4、5、7、10、12、14、15、16、18、20、22、25、28、30、40、45或48)，可选地为5至20。缓解了高工作电压下第一锂盐导致的铝箔腐蚀问题。
在一些实施方式中，第一添加剂的含量为W2重量％，W2为0.01至20(比如为0.01、0.05、0.1、0.2、0.3、0.4、0.5、1、2、3、4、5、8、10、12、15、18或20)，可选地为0.1至10或0.3至5，当第一添加剂在电解液中的质量占比处于上述范围时，既能降低电解液酸度，减小锰离子溶出，又避免对负极阻抗的恶化，进而改善锂离子电池的高温循环和存储性能，同时不影响锂离子电池容量发挥和倍率性能。
在一些实施方式中，上述W2/W1定义为M，M为0.001至3(比如为0.001、0.002、0.005、0.007、0.1、0.2、0.3、0.4、0.5、1、2或3)，可选地为0.005至0.5。当W2/W1处于上述范围时，二者可以发挥更好地协同作用，保证体系酸度较低，锰离子溶出减小，锂离子高温循环和存储性能优异。
在控制第一锂盐含量的基础上，一些实施方式中可以通过添加第二锂盐来补充非水电解液中的锂盐，即非水电解液还包括第二锂盐，第二锂盐包括选自二氟磷酸锂、二氟二草酸磷酸锂、二氟草酸硼酸锂、双草酸硼酸锂、LiPF 6、LiBF 4中的一种或多种。非水电解液中加入上述第二锂盐作为锂盐型添加剂，其会优先在铝箔表面发生分解，分解产物与铝离子结合生成的不溶或难溶的沉淀附着在铝箔的表面，从而形成一层钝化膜，防止了铝箔与电解液的直接接触，保护了铝箔，进而协同第一锂盐改善高温循环和存储性能。
在一些实施方式中，基于非水电解液的总重量，第二锂盐的含量为W3重量％，W3为0.01至20(比如为0.01、0.02、0.05、0.08、0.1、0.2、0.3、0.5、0.8、1、2、3、4、5、6、7、8、9、10、15、20)，可选地为0.1至10或0.3至5。当第二锂盐在电解液中的质量占比处于上述范围时，既能抑制铝箔腐蚀，改善锂离子电池的高温循环和存储性能，同时不恶化锂离子电池容量发挥和倍率性能。
在一些实施方式中，(W2+W3)/W1定义为N，N为0.01至5(比如为0.01、0.02、0.05、0.08、0.1、0.5、0.8、1.0、2、3、4或5)，可选地0.02至1。当W2/W1、(W2+W3)/W1处于上述范围时，三者可以发挥更好地协同作用，保证 体系酸度较低，锰离子溶出减小，锂离子高温循环和存储性能优异；同时有效抑制铝箔腐蚀，改善锂离子电池的高温循环和存储性能，同时不恶化锂离子电池容量发挥和倍率性能。
在一些实施方式中，上述非水电解液还包括第二添加剂，第二添加剂包括含有不饱和键的环状碳酸酯化合物、卤素取代的饱和环状碳酸酯化合物、硫酸酯化合物、亚硫酸酯化合物、磺酸内酯化合物、二磺酸化合物、腈化合物、芳香化合物、磷腈化合物、环状酸酐化合物、亚磷酸酯化合物、磷酸酯化合物、硼酸酯化合物组成的组中的一种或多种。本领域技术人员可以根据实际需求从上述物质中选择相应的第二添加剂，且第二添加剂在非水电解液中的用量也可以以现有技术为参考，本申请不再赘述。
在一些实施方式中，上述非水电解液还包括有机溶剂，有机溶剂的种类没有特别的限制，可根据实际需求进行选择，具体地，有机溶剂包括环状碳酸酯化合物、链状碳酸酯化合物、羧酸酯化合物中的一种或多种，可选地，有机溶剂包括碳酸二甲酯、碳酸二乙酯、碳酸二丙酯、碳酸甲乙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸乙烯酯、碳酸丙烯酯、碳酸丁烯酯、γ-丁内酯、甲酸甲酯、甲酸乙酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丁酯、四氢呋喃组成的组中的一种或多种。
在一些实施方式中，正极活性材料的A、C和D各自独立地为上述各自范围内的任一种元素，并且所述B为至少两种元素。由此，能够更容易且准确地控制正极活性材料的组成。
可选地，
A为选自Mg和Nb中的任一种元素，和/或，
B为选自Fe、Ti、V、Co和Mg的至少两种元素，可选地为Fe与选自Ti、V、Co和Mg的一种以上元素，和/或，
C为S，和/或，
D为F。
通过在上述范围内对Li位掺杂元素进行选择，能够进一步减小脱锂过程中的晶格变化率，从而进一步改善电池的倍率性能。通过在上述范围内对Mn位掺杂元素进行选择，能够进一步提高电子电导率并进一步减小晶格变化率，从而提升电池的倍率性能和克容量。通过在上述范围内对P位掺杂元素进行选择，能够进一步改善电池的倍率性能。通过在上述范围内对O位掺杂元素进行选择，能够进一步减轻界面的副反应，提升电池的高温性能。
在一些实施方式中，x选自0.001至0.005的范围(比如x为0.001、0.002、0.003、0.004或0.005)；和/或，y选自0.01至0.5的范围(比如y为0.01、0.02、 0.03、0.04、0.05、0.1、0.2、0.25、0.30、0.35、0.40、0.45或0.50)，可选地选自0.25至0.5的范围；和/或，z选自0.001至0.005的范围(比如z为0.001、0.002、0.003、0.004或0.005)；和/或，n选自0.001至0.005的范围(比如n为0.001、0.002、0.003、0.004或0.005)。通过在上述范围内对y值进行选择，能够进一步提升材料的克容量和倍率性能。通过在上述范围内对x值进行选择，能够进一步提升材料的动力学性能。通过在上述范围内对z值进行选择，能够进一步提升二次电池的倍率性能。通过在上述范围内对n值进行选择，能够进一步提升二次电池的高温性能。
在一些实施方式中，正极活性材料满足：(1-y):y在1至4范围内，可选地在1.5至3范围内，且a:x在9到1100范围内，可选地在190-998范围内。此处y表示Mn位掺杂元素的化学计量数之和。在满足上述条件时，正极活性材料的能量密度和循环性能可进一步提升。
在一些实施方式中，正极活性材料的晶格变化率为8％以下，可选地，晶格变化率为4％以下。通过降低晶格变化率，能够使得Li离子传输更容易，即Li离子在材料中的迁移能力更强，有利于改善二次电池的倍率性能。晶格变化率可通过本领域中已知的方法，例如X射线衍射图谱(XRD)测得。
在一些实施方式中，正极活性材料的Li/Mn反位缺陷浓度为2％以下，可选地，Li/Mn反位缺陷浓度为0.5％以下。所谓Li/Mn反位缺陷，指的是LiMnPO 4晶格中，Li +与Mn 2+的位置发生互换。Li/Mn反位缺陷浓度指的是正极活性材料中与Mn 2+发生互换的Li +占Li +总量的百分比。反位缺陷的Mn 2+会阻碍Li +的传输，通过降低Li/Mn反位缺陷浓度，有利于提高正极活性材料的克容量和倍率性能。Li/Mn反位缺陷浓度可通过本领域中已知的方法，例如XRD测得。
在一些实施方式中，正极活性材料的表面氧价态为-1.82以下，可选地为-1.89～-1.98。通过降低表面氧价态，能够减轻正极活性材料与电解液的界面副反应，从而改善二次电池的循环性能和高温稳定性。表面氧价态可通过本领域中已知的方法测量，例如通过电子能量损失谱(EELS)测量。
在一些实施方式中，正极活性材料在3T(吨)下的压实密度为2.0g/cm 3以上，可选地为2.2g/cm 3以上。压实密度越高，单位体积活性材料的重量越大，因此提高压实密度有利于提高电芯的体积能量密度。压实密度可依据GB/T24533-2009测量。
在一些实施方式中，正极活性材料表面包覆有碳。由此，可以改善正极活性材料的导电性。
本申请的第二方面还提供一种电池模块，该电池模块包括二次电池，该二次电池为本申请的任意一种上述二次电池。
本申请的第三方面还提供一种电池包，该电池包包括电池模块，该电池模块 为本申请的上述电池模块。
本申请的第四方面还提供一种用电装置，该用电装置包括二次电池、电池模块或电池包中的至少一种，上述二次电池、电池模块和电池包均为本申请的提供的二次电池、电池模块、电池包。
由此，本申请的电池模块、电池包具有较高的循环性能、倍率特性，尤其是高温稳定性也有明显改善，进而为具有本申请二次电池、电池模块或电池包的用电装置提供了较高的动力循环稳定性和高温运行稳定性。
附图说明
图1是本申请一实施方式的二次电池的示意图。
图2是图1所示的本申请一实施方式的二次电池的分解图。
图3是本申请一实施方式的电池模块的示意图。
图4是本申请一实施方式的电池包的示意图。
图5是图4所示的本申请一实施方式的电池包的分解图。
图6是本申请一实施方式的二次电池用作电源的用电装置的示意图。
附图标记说明：
1电池包；2上箱体；3下箱体；4电池模块；5二次电池；51壳体；52电极组件；53顶盖组件
具体实施方式
以下，适当地参照附图详细说明具体公开了本申请的二次电池、电池模块、电池包和用电装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。 此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
[二次电池]
二次电池又称为充电电池或蓄电池，是指在电池放电后可通过充电的方式使活性材料激活而继续使用的电池。
通常情况下，二次电池包括正极极片、负极极片、隔离膜及电解液。在电池充放电过程中，活性离子(例如锂离子)在正极极片和负极极片之间往返嵌入和脱出。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的作用，同时可以使活性离子通过。电解液在正极极片和负极极片之间，主要起到传导活性离子的作用。
本申请的一个实施方式提供一种二次电池，包括正极极片以及非水电解液，其中，正极极片包括正极活性材料，正极活性材料具有化学式 Li aA xMn 1-yB yP 1-zC zO 4-nD n，其中，A包括选自Zn、Al、Na、K、Mg、Nb、Mo和W组成的组中的一种或多种元素，B包括选自Ti、V、Zr、Fe、Ni、Mg、Co、Ga、Sn、Sb、Nb和Ge组成的组中的一种或多种元素，C包括选自B(硼)、S、Si和N组成的组中的一种或多种元素，D包括选自S、F、Cl和Br组成的组中的一种或多种元素，a选自0.9至1.1的范围，x选自0.001至0.1的范围，y选自0.001至0.5的范围，z选自0.001至0.1的范围，n选自0.001至0.1的范围，并且正极活性材料为电中性的；
非水电解液包括第一锂盐和第一添加剂，可选地，第一锂盐包括选自LiN(C mF 2m+1SO 2)(C nF 2n+1SO 2)、Li(FSO 2) 2N组成的组中的一种或多种，m、n表示正整数；
第一添加剂包括式1所示化合物中的一种或多种，
Figure PCTCN2022084859-appb-000006
R 1表示经一个或多个R a取代或未取代的C2～C10亚烷基、C2～C10杂亚烷基、C6～C18亚芳基、C2～C18杂亚芳基、C3～C18亚脂环基、C3～C18杂亚脂环基中的任意一种，
R a包括选自卤原子、-CN、-NCO、-OH、-COOH、-SOOH、-COOR b、C2～C10烷基、C2～C10烯基、C2～C10炔基、C2～C10氧杂烷基中的一种或多种，R b选自C1-C10烷基中的任意一种。
正极极片通常包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，正极膜层包括正极活性材料。
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极膜层设置在正极集流体相对的两个表面的其中任意一者或两者上。
在一些实施方式中，正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
本申请的正极活性材料通过在化合物LiMnPO 4中进行元素掺杂而获得，其中，A、B、C和D分别为在化合物LiMnPO 4的Li位、Mn位、P位和O位掺杂的元素。不希望囿于理论，现认为磷酸锰锂的性能提升与减小脱嵌锂过程中磷酸锰锂的晶格变化率和降低表面活性有关。减小晶格变化率可减小晶界处两相间的晶格常数差异，减小界面应力，增强Li +在界面处的传输能力，从而提升正极活性材料的倍率性能。而表面活性高容易导致界面副反应严重，加剧产气、电解液 消耗和破坏界面，从而影响电池的循环等性能。本申请中，通过Li和Mn位掺杂减小了晶格变化率。Mn位掺杂还有效降低表面活性，从而抑制锰离子溶出和正极活性材料与电解液的界面副反应。P位掺杂使Mn-O键长的变化速率更快，降低材料的小极化子迁移势垒，从而有利于电子电导率。O位掺杂对减小界面副反应有良好的作用。P位和O位的掺杂还对反位缺陷的锰离子溶出及动力学性能产生影响。因此，掺杂减小了材料中反位缺陷浓度，提高材料的动力学性能和克容量，还可以改变颗粒的形貌，从而提升压实密度。本申请人意外地发现：通过在化合物LiMnPO 4的Li位、Mn位、P位和O位同时以本申请的特定量掺杂特定的元素，能够获得明显改善的倍率性能，同时显著减少了Mn与Mn位掺杂元素的溶出，获得了显著改善的循环性能和/或高温稳定性，并且材料的克容量和压实密度也可以得到提高。
同时，非水电解液以第一锂盐为主锂盐，由于其优异的热稳定性和耐水解能力，可以有效降低电解液酸度，减小锰离子溶出，改善高温循环和存储性能；非水电解液中引入式1所示的异氰酸酯基化合物，可与电池中的痕量水反应生成-NHCOOH，防止痕量水与非水电解液作用产生HF，进一步降低电解液酸度和减小锰离子溶出，进而改善高温循环和存储性能。此外，式1所示的异氰酸酯基化合物还可以在负极成膜生成均匀的SEI膜，减小溶出的Mn在负极还原，进一步改善高温循环和存储性能。
在一些实施方式中，非水电解液包括第一锂盐和第一添加剂，且第一锂盐作为主锂盐存在。上述第一锂盐中的LiN(C mF 2m+1SO 2)(C nF 2n+1SO 2)可以从现有技术中任意的相应具体物质中选择，在一些实施方式中，m、n各自独立地表示1、2或3，以提供更优异的热稳定性。比如第一锂盐选自LiN(C mF 2m+1SO 2)(C nF 2n+1SO 2)、Li(FSO 2) 2N组成的组中的任意一种或多种，比如其可以在(氟磺酰亚胺)(三氟甲磺酰亚胺)锂Li(FSO 2)(CF 3SO 2)N、双(三氟甲磺酰亚胺)锂(LiN(CF 3SO 2) 2)、双(五氟乙磺酰亚胺)锂(LiN(C 2F 5SO 2) 2)、(三氟甲磺酰亚胺)(五氟乙磺酰亚胺)锂(LiN(CF 3SO 2)(C 2F 5SO 2))、(三氟甲磺酰亚胺)(七氟丙磺酰亚胺)锂(LiN(CF 3SO 2)(C 3F 7SO 2))、(三氟甲磺酰亚胺)(九氟丁磺酰亚胺)锂(LiN(CF 3SO 2)(C 4F 9SO 2))、(五氟乙磺酰亚胺)(七氟丙磺酰亚胺)锂LiN(C 2F 5SO 2)(C 3F 7SO 2)、Li(FSO 2) 2N等物质中进行选择。
用于本申请的1所示异氰酸酯化合物可以从现有技术中电解液常用的异氰酸酯类化合物中进行选择，在一些实施方式中，上述R 1表示经一个或多个R a取代或未取代的C2～C10亚烷基、C2～C10氧杂亚烷基、C2～C10氮杂亚烷基、亚苯基、亚萘基、亚蒽基、亚环丁基、亚环戊基、亚环己基、亚联苯基、亚甲基二亚苯基中的任意一种，可选地R 1表示经一个或多个R a取代或未取代的C2～C6亚烷基、亚苯基、亚萘基、亚蒽基、亚环丁基、亚环戊基、亚环己基、亚联苯基、亚甲基二亚苯基中的任意一种；和/或R a包括选自卤原子、-CN、C2～C3烷基中的一种或多种；和/或式1所示化合物中R a的个数为0、1、2、3或4个。 可选地，上述第一添加剂包括如下化合物中的一种或多种：
Figure PCTCN2022084859-appb-000007
Figure PCTCN2022084859-appb-000008
上述各化合物在非水电解液的溶剂中具有良好的分散溶解性能，可充分与电池中的痕量水反应-NHCOOH，防止痕量水与非水电解液作用产生HF，进一步降低电解液酸度和减小锰离子溶出，进而改善高温循环和存储性能。此外，上述各异氰酸酯基化合物在负极更易生成均匀的SEI膜，更有利于减小溶出的Mn在负极还原，进一步改善高温循环和存储性能。
在本申请的一些实施方式中，当第一锂盐选自LiN(CF 3SO 2) 2、Li(FSO 2) 2N中的任意一种，第一添加剂选自如下化合物中的任意一种：
Figure PCTCN2022084859-appb-000009
此时，二者的优势得到充分发挥且电解液酸度和Mn离子溶出显著降低，锂离子电池的高温循环和存储性能得到显著改善。
采用上述第一锂盐作为非水电解液的主锂盐虽然可以有效改善二次电池的高温循环和存储性能，但是在某些条件下该物质会腐蚀锂盐，比如当锂离子电池的工作电压＞4.2V时会存在铝箔腐蚀的问题，其中可能的机理是铝箔表面原始的氧化膜在电解液中遭到破坏后，暴露出了活性更高的铝，然后铝发生氧化产生 Al 3+离子，接着电解液中的FSI-或TFSI-和Al 3+结合形成可溶性的Al(FSI) 3或Al(TFSI) 3，Al(FSI) 3或Al(TFSI) 3溶解后造成了铝的腐蚀。因此为了缓解高工作电压下第一锂盐导致的铝箔腐蚀问题，在一些实施方式中，基于非水电解液的总重量，第一锂盐的含量为W1重量％，W1为0.1至48，可选地为5至20。
在控制第一锂盐含量的基础上，一些实施方式中可以通过添加第二锂盐来补充非水电解液中的锂盐，即非水电解液还包括第二锂盐，第二锂盐包括选自二氟磷酸锂、二氟二草酸磷酸锂、二氟草酸硼酸锂、双草酸硼酸锂、LiPF 6、LiBF 4中的一种或多种。非水电解液中加入上述第二锂盐作为锂盐型添加剂，其会优先在铝箔表面发生分解，分解产物与铝离子结合生成的不溶或难溶的沉淀附着在铝箔的表面，从而形成一层钝化膜，防止了铝箔与电解液的直接接触，保护了铝箔，进而协同第一锂盐改善高温循环和存储性能。
但是过多的锂盐型添加剂，又会使正负极阻抗增大，使锂离子电池容量异常、倍率性能变差。在一些实施方式中，基于非水电解液的总重量，第二锂盐的含量为W3重量％，W3为0.01至20，可选地为0.1至10或0.3至5。当第二锂盐在电解液中的质量占比处于上述范围时，既能抑制铝箔腐蚀，改善锂离子电池的高温循环和存储性能，同时不恶化锂离子电池容量发挥和倍率性能。
虽然第一添加剂可在负极成膜生成均匀的SEI膜，减小溶出的Mn在负极还原，进一步改善高温循环和存储性能。但是过多的异氰酸酯基化合物又会使负极阻抗增大，使锂离子电池容量异常、倍率性能变差。可选地，第一添加剂的含量为W2重量％，W2为0.01至20，可选地为0.1至10或0.3至5，当第一添加剂在电解液中的质量占比处于上述范围时，既能降低电解液酸度，减小锰离子溶出，又避免对负极阻抗的恶化，进而改善锂离子电池的高温循环和存储性能，同时不影响锂离子电池容量发挥和倍率性能。
在一些实施方式中，上述W2/W1定义为M，M为0.001至3，可选地0.005至0.5。(W2+W3)/W1定义为N，N为0.01至2，可选地0.02至1。
当W2/W1、(W2+W3)/W1处于上述范围时，三者可以发挥更好地协同作用，保证体系酸度较低，锰离子溶出减小，锂离子高温循环和存储性能优异；同时有效抑制铝箔腐蚀，改善锂离子电池的高温循环和存储性能，同时不恶化锂离子电池容量发挥和倍率性能。
在一些实施方式中，上述非水电解液还包括第二添加剂，第二添加剂包括含有不饱和键的环状碳酸酯化合物、卤素取代的饱和环状碳酸酯化合物、硫酸酯化合物、亚硫酸酯化合物、磺酸内酯化合物、二磺酸化合物、腈化合物、芳香化合物、磷腈化合物、环状酸酐化合物、亚磷酸酯化合物、磷酸酯化合物、硼酸酯化合物组成的组中的一种或多种。本领域技术人员可以根据实际需求从上述物质中选择相应的第二添加剂，且第二添加剂在非水电解液中的用量也可以以现有技术 为参考，本申请不再赘述。
在一些实施方式中，上述非水电解液还包括有机溶剂，有机溶剂的种类没有特别的限制，可根据实际需求进行选择，具体地，有机溶剂包括环状碳酸酯化合物、链状碳酸酯化合物、羧酸酯化合物中的一种或多种，可选地，有机溶剂包括碳酸二甲酯、碳酸二乙酯、碳酸二丙酯、碳酸甲乙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸乙烯酯、碳酸丙烯酯、碳酸丁烯酯、γ-丁内酯、甲酸甲酯、甲酸乙酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丁酯、四氢呋喃组成的组中的一种或多种。
在一些实施方式中，正极活性材料的A、C和D各自独立地为上述各自范围内的任一种元素，并且所述B为至少两种元素。由此，能够更容易且准确地控制正极活性材料的组成。
可选地，
A为选自Mg和Nb中的任一种元素，和/或，
B为选自Fe、Ti、V、Co和Mg的至少两种元素，可选地为Fe与选自Ti、V、Co和Mg的一种以上元素，和/或，
C为S，和/或，
D为F。
通过在上述范围内对Li位掺杂元素进行选择，能够进一步减小脱锂过程中的晶格变化率，从而进一步改善电池的倍率性能。通过在上述范围内对Mn位掺杂元素进行选择，能够进一步提高电子电导率并进一步减小晶格变化率，从而提升电池的倍率性能和克容量。通过在上述范围内对P位掺杂元素进行选择，能够进一步改善电池的倍率性能。通过在上述范围内对O位掺杂元素进行选择，能够进一步减轻界面的副反应，提升电池的高温性能。
在一些实施方式中，x选自0.001至0.005的范围；和/或，y选自0.01至0.5的范围，可选地选自0.25至0.5的范围；和/或，z选自0.001至0.005的范围；和/或，n选自0.001至0.005的范围。通过在上述范围内对y值进行选择，能够进一步提升材料的克容量和倍率性能。通过在上述范围内对x值进行选择，能够进一步提升材料的动力学性能。通过在上述范围内对z值进行选择，能够进一步提升二次电池的倍率性能。通过在上述范围内对n值进行选择，能够进一步提升二次电池的高温性能。
在一些实施方式中，正极活性材料满足：(1-y):y在1至4范围内，可选地在1.5至3范围内，且a:x在9到1100范围内，可选地在190-998范围内。此处y表示Mn位掺杂元素的化学计量数之和。在满足上述条件时，正极活性材料的能量密度和循环性能可进一步提升。
在一些实施方式中，正极活性材料的晶格变化率为8％以下，可选地，晶格变化率为4％以下。通过降低晶格变化率，能够使得Li离子传输更容易，即Li离子在材料中的迁移能力更强，有利于改善二次电池的倍率性能。晶格变化率可通过本领域中已知的方法，例如X射线衍射图谱(XRD)测得。
在一些实施方式中，正极活性材料的Li/Mn反位缺陷浓度为2％以下，可选地，Li/Mn反位缺陷浓度为0.5％以下。所谓Li/Mn反位缺陷，指的是LiMnPO4晶格中，Li +与Mn 2+的位置发生互换。Li/Mn反位缺陷浓度指的是正极活性材料中与Mn 2+发生互换的Li +占Li +总量的百分比。反位缺陷的Mn 2+会阻碍Li +的传输，通过降低Li/Mn反位缺陷浓度，有利于提高正极活性材料的克容量和倍率性能。Li/Mn反位缺陷浓度可通过本领域中已知的方法，例如XRD测得。
在一些实施方式中，正极活性材料的表面氧价态为-1.82以下，可选地为-1.89～-1.98。通过降低表面氧价态，能够减轻正极活性材料与电解液的界面副反应，从而改善二次电池的循环性能和高温稳定性。表面氧价态可通过本领域中已知的方法测量，例如通过电子能量损失谱(EELS)测量。
在一些实施方式中，正极活性材料在3T(吨)下的压实密度为2.0g/cm 3以上，可选地为2.2g/cm 3以上。压实密度越高，单位体积活性材料的重量越大，因此提高压实密度有利于提高电芯的体积能量密度。压实密度可依据GB/T24533-2009测量。
在一些实施方式中，正极活性材料表面包覆有碳。由此，可以改善正极活性材料的导电性。
以下对本申请的正极活性材料的准备方法进行说明，但是以下说明仅为示例性说明，本领域技术人员可以采用其他能够实现的方法来制备本申请的正极活性材料。
在一些实施方式中，正极活性材料的制备方法包括：步骤(1)：将锰源、元素B的源和酸在溶剂中溶解并搅拌，生成掺杂元素B的锰盐的悬浊液，将悬浊液过滤并烘干滤饼，得到掺杂了元素B的锰盐；步骤(2)：将锂源、磷源、元素A的源、元素C的源和元素D的源、溶剂和由步骤(1)获得的掺杂了元素B的锰盐加入反应容器中研磨并混合，得到浆料；步骤(3)：将由步骤(2)获得的浆料转移到喷雾干燥设备中进行喷雾干燥造粒，得到颗粒；步骤(4)：将由步骤(3)获得的颗粒进行烧结，得到上述正极活性材料。
可选地，上述步骤(1)的搅拌在60-120℃范围内的温度下进行，和/或，步骤(1)的搅拌通过在200-800rpm的搅拌速率下进行。
可选地，上述步骤(2)的研磨并混合进行8-15小时。
可选地，上述步骤(4)的烧结在600-900℃的温度范围内进行6-14小时。
可选地，上述元素A的源选自元素A的单质、氧化物、磷酸盐、草酸盐、碳酸盐和硫酸盐中的至少一种，元素B的源选自元素B的单质、氧化物、磷酸盐、草酸盐、碳酸盐和硫酸盐中的至少一种，元素C的源选自元素C的硫酸盐、硼酸盐、硝酸盐和硅酸盐中的至少一种，元素D的源选自元素D的单质和铵盐中的至少一种。
在一些实施方式中，正极膜层还可包含本领域公知的用于二次电池的其它正极活性材料。作为示例，正极活性材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作二次电池正极活性材料的传统材料。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用。其中，锂过渡金属氧化物的示例可包括但不限于锂镍氧化物(如LiNiO 2)、锂锰氧化物(如LiMnO 2、LiMn 2O 4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物及其改性化合物等中的至少一种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO 4(也可以简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO 4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料中的至少一种。
在一些实施方式中，正极膜层还可选地包括粘结剂。作为示例，粘结剂可以包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。
在一些实施方式中，正极膜层还可选地包括导电剂。作为示例，导电剂可以包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片。
[负极极片]
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，所述负极膜层包括负极活性材料。
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极膜层设置在负极集流体相对的两个表面中的任意一者或两者上。
在一些实施方式中，负极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、 镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，负极活性材料可采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的至少一种。锡基材料可选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性材料的传统材料。这些负极活性材料可以仅单独使用一种，也可以将两种以上组合使用。
在一些实施方式中，负极膜层还可选地包括粘结剂。作为示例，粘结剂可选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的至少一种。
在一些实施方式中，负极膜层还可选地包括导电剂。作为示例，导电剂可选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，负极膜层还可选地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。
在一些实施方式中，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到负极极片。
[隔离膜]
在一些实施方式中，二次电池中还包括隔离膜。本申请对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。
在一些实施方式中，隔离膜的材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的至少一种。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。
在一些实施方式中，二次电池可包括外包装。该外包装可用于封装上述电极 组件及电解质。
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，作为塑料，可列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。例如，图1是作为一个示例的方形结构的二次电池5。
在一些实施方式中，参照图2，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔内。电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或多个，本领域技术人员可根据具体实际需求进行选择。
在一些实施方式中，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为一个或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。
图3是作为一个示例的电池模块4。参照图3，在电池模块4中，多个二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间。
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以为一个或多个，具体数量本领域技术人员可根据电池包的应用和容量进行选择。
图4和图5是作为一个示例的电池包1。参照图4和图5，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
另外，本申请还提供一种用电装置，所述用电装置包括本申请提供的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以包括移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动 高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等，但不限于此。
作为所述用电装置，可以根据其使用需求来选择二次电池、电池模块或电池包。
图6是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
[实施例]
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
其中，第一添加剂选自如下化合物：
化合物1：
Figure PCTCN2022084859-appb-000010
化合物2:
Figure PCTCN2022084859-appb-000011
化合物3：
Figure PCTCN2022084859-appb-000012
化合物4：
Figure PCTCN2022084859-appb-000013
化合物5：
Figure PCTCN2022084859-appb-000014
实施例1
1)正极活性材料的制备
制备掺杂的草酸锰：将1.3mol的MnSO 4﹒H 2O、0.7mol的FeSO 4﹒H 2O在混料机中充分混合6小时。将混合物转移至反应釜中，并加入10L去离子水和2mol二水合草酸(以草酸计)。将反应釜加热至80℃，以600rpm的转速搅拌6小时，反应终止(无气泡产生)，得到Fe掺杂的草酸锰悬浮液。然后过滤所述悬浮液，将滤饼在120℃下烘干，之后进行研磨，得到中值粒径Dv 50为100nm左右的Fe掺杂的草酸锰颗粒。
制备掺杂的磷酸锰锂：取1mol上述草酸锰颗粒、0.497mol碳酸锂、0.001mol的Mo(SO 4) 3、含有0.999mol磷酸的浓度为85％的磷酸水溶液、0.001mol的H 4SiO 4、0.0005mol的NH 4HF 2和0.005mol蔗糖加入到20L去离子水中。将混合物转入砂磨机中充分研磨搅拌10小时，得到浆料。将所述浆料转移到喷雾干燥设备中进行喷雾干燥造粒，设定干燥温度为250℃，干燥4小时，得到颗粒。在氮气(90 体积％)+氢气(10体积％)保护气氛中，将上述粉料在700℃下烧结10小时，得到碳包覆的Li 0.994Mo 0.001Mn 0.65Fe 0.35P 0.999Si 0.001O 3.999F 0.001。正极活性材料可用电感耦合等离子体发射光谱(ICP)进行元素含量的检测。
2)扣式电池的制备
将上述正极活性材料、聚偏二氟乙烯(PVDF)、乙炔黑以90：5：5的重量比加入至N-甲基吡咯烷酮(NMP)中，在干燥房中搅拌制成浆料。在铝箔上涂覆上述浆料，干燥、冷压制成正极极片。涂覆量为0.2g/cm 2，压实密度为2.0g/cm 3。
采用锂片作为负极，采用Li(FSO 2) 2N(第一锂盐，在电解液中的质量含量为15％)、化合物1(第一添加剂，在电解液中的质量含量为1％)、LiPF 6(第二锂盐，在电解液中的质量含量为3％)1mol/L在体积比1：1：1的碳酸乙烯酯(EC)、碳酸二乙酯(DEC)和碳酸二甲酯(DMC)中的溶液为电解液，其中控制对应单位面积的正极活性材料的第一锂盐和第一添加剂总量为5.4mg/m 2，与上述制备的正极极片一起在扣电箱中组装成扣式电池(下文也称“扣电”)。
3)全电池的制备
将上述正极活性材料与导电剂乙炔黑、粘结剂聚偏二氟乙烯(PVDF)按重量比92：2.5：5.5在N-甲基吡咯烷酮溶剂体系中混合均匀后，涂覆于铝箔上并烘干、冷压，得到正极极片。涂覆量为0.4g/cm 2，压实密度为2.4g/cm 3。
将负极活性材料人造石墨、硬碳、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC)按照重量比90：5：2：2：1在去离子水中混合均匀后，涂覆于铜箔上烘干、冷压，得到负极极片。涂覆量为0.2g/cm 2，压实密度为1.7g/cm 3。
以聚乙烯(PE)多孔聚合薄膜作为隔离膜，将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正负极中间起到隔离的作用，并卷绕得到裸电芯。将裸电芯置于外包装中，注入与上述制备扣电时相同的电解液并封装，得到全电池(下文也称“全电”)。
实施例2
除了在“1)正极活性材料的制备”中，将高纯Li 2CO 3的量改变为0.4885mol，将Mo(SO 4) 3换成MgSO 4，将FeSO 4﹒H 2O的量改变为0.68mol，在制备掺杂的草酸锰时还加入0.02mol的Ti(SO 4) 2，并将H 4SiO 4换成HNO 3之外，其他与实施例1相同。
实施例3
除了在“1)正极活性材料的制备”中，将高纯Li 2CO 3的量改变为0.496mol，将Mo(SO 4) 3换成W(SO 4) 3，将H 4SiO 4换成H 2SO 4之外，其他与实施例1相同。
实施例4
除了在“1)正极活性材料的制备”中，将高纯Li 2CO 3的量改变为0.4985mol，将0.001mol的Mo(SO 4) 3换成0.0005mol的Al 2(SO 4) 3和NH 4HF 2换成NH 4HCl 2之外，其他与实施例1相同。
实施例5
除了在“1)正极活性材料的制备”中，将0.7mol的FeSO 4﹒H 2O改为0.69mol，在制备掺杂的草酸锰时还加入0.01molVCl 2，将Li 2CO 3的量改变为0.4965mol，将0.001mol的Mo(SO 4) 3换成0.0005mol的Nb 2(SO 4) 5和H 4SiO 4换成H 2SO 4之外，其他与实施例1相同。
实施例6
除了在“1)正极活性材料的制备”中，将FeSO 4﹒H 2O的量改为0.68mol，在制备掺杂的草酸锰时还加入0.01mol的VCl 2和0.01mol的MgSO 4，将Li 2CO 3的量改变为0.4965mol，将0.001mol的Mo(SO 4) 3换成0.0005mol的Nb 2(SO 4) 5和H 4SiO 4换成H 2SO 4之外，其他与实施例1相同。
实施例7
除了在“1)正极活性材料的制备”中，将MgSO 4换成CoSO 4之外，其他与实施例6相同。
实施例8
除了在“1)正极活性材料的制备”中，将MgSO 4换成NiSO 4之外，其他与实施例6相同。
实施例9
除了在“1)正极活性材料的制备”中，将FeSO 4﹒H 2O的量改为0.698mol，在制备掺杂的草酸锰时还加入0.002mol的Ti(SO 4) 2，将Li 2CO 3的量改变为0.4955mol，将0.001mol的Mo(SO 4) 3换成0.0005mol的Nb 2(SO 4) 5，H 4SiO 4换成H 2SO 4，NH 4HF 2制成NH 4HCl 2之外，其他与实施例1相同。
实施例10
除了在“1)正极活性材料的制备”中，将FeSO 4﹒H 2O的量改为0.68mol，在制备掺杂的草酸锰时还加入0.01mol的VCl 2和0.01mol的MgSO 4，将Li 2CO 3的量改变为0.4975mol，将0.001mol的Mo(SO 4) 3换成0.0005mol的Nb 2(SO 4) 5和NH 4HF 2换成NH 4HBr 2之外，其他与实施例1相同。
实施例11
除了在“1)正极活性材料的制备”中，将FeSO 4﹒H 2O的量改为0.69mol，在 制备掺杂的草酸锰时还加入0.01mol的VCl 2，将Li 2CO 3的量改变为0.499mol，将Mo(SO 4) 3换成MgSO 4和NH 4HF 2换成NH 4HBr 2之外，其他与实施例1相同。
实施例12
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.36mol，将FeSO 4﹒H 2O的量改为0.6mol，在制备掺杂的草酸锰时还加入0.04mol的VCl 2，将Li 2CO 3的量改变为0.4985mol，将Mo(SO 4) 3换成MgSO 4和H 4SiO 4换成HNO 3之外，其他与实施例1相同。
实施例13
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.16mol，FeSO 4﹒H 2O的量改为0.8mol之外，其他与实施例12相同。
实施例14
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.3mol，VCl 2的量改为0.1mol之外，其他与实施例12相同。
实施例15
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.2mol，在制备掺杂的草酸锰时还加入0.1mol的VCl 2，将Li 2CO 3的量改变为0.494mol，将0.001mol的Mo(SO 4) 3换成0.005mol的MgSO 4和H 4SiO 4换成H 2SO 4之外，其他与实施例1相同。
实施例16
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.2mol，在制备掺杂的草酸锰时还加入0.1mol的VCl 2，将Li 2CO 3的量改变为0.467mol，将0.001mol的Mo(SO 4) 3换成0.005mol的MgSO 4，0.001mol的H 4SiO 4换成0.005mol的H 2SO 4和1.175mol浓度为85％的磷酸换成1.171mol浓度为85％的磷酸之外，其他与实施例1相同。
实施例17
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.2mol，在制备掺杂的草酸锰时还加入0.1mol的VCl 2，将Li 2CO 3的量改变为0.492mol，将0.001mol的Mo(SO 4) 3换成0.005mol的MgSO 4，H 4SiO 4换成H 2SO 4和0.0005mol的NH 4HF 2改成0.0025mol之外，其他与实施例1相同。
实施例18
除了在“1)正极活性材料的制备”中，将FeSO 4﹒H 2O的量改为0.5mol，在制备掺杂的草酸锰时还加入0.1mol的VCl 2和0.1mol的CoSO 4，将Li 2CO 3的量 改变为0.492mol，将0.001mol的Mo(SO 4) 3换成0.005mol的MgSO 4，H 4SiO 4换成H 2SO 4和0.0005mol的NH 4HF 2改成0.0025mol之外，其他与实施例1相同。
实施例19
除了在“1)正极活性材料的制备”中，将FeSO 4﹒H 2O的量改为0.4mol，将0.1mol的CoSO 4改为0.2mol之外，其他与实施例18相同。
实施例20
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.5mol，FeSO 4﹒H 2O的量改为0.1mol，CoSO 4的量改为0.3mol之外，其他与实施例18相同。
实施例21
除了在“1)正极活性材料的制备”中，将0.1mol的CoSO 4换成0.1mol的NiSO 4之外，其他与实施例18相同。
实施例22
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.5mol，FeSO 4﹒H 2O的量改为0.2mol，将0.1mol的CoSO 4换成0.2mol的NiSO 4之外，其他与实施例18相同。
实施例23
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.4mol，FeSO 4﹒H 2O的量改为0.3mol，CoSO 4的量改为0.2mol之外，其他与实施例18相同。
实施例24
除了在“1)正极活性材料的制备”中，将1.3mol的MnSO 4﹒H 2O改为1.2mol，0.7mol的FeSO 4﹒H 2O改为0.5mol，在制备掺杂的草酸锰时还加入0.1mol的VCl 2和0.2mol的CoSO 4，将Li 2CO 3的量改变为0.497mol，将0.001mol的Mo(SO 4) 3换成0.005mol的MgSO 4，H 4SiO 4换成H 2SO 4和0.0005mol的NH 4HF 2改成0.0025mol之外，其他与实施例1相同。
实施例25
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.0mol，FeSO 4﹒H 2O的量改为0.7mol，CoSO 4的量改为0.2mol之外，其他与实施例18相同。
实施例26
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.4mol，FeSO 4﹒H 2O的量改为0.3mol，在制备掺杂的草酸锰时还加入0.1mol的VCl 2和0.2mol 的CoSO 4，将Li 2CO 3的量改变为0.4825mol，将0.001mol的Mo(SO 4) 3换成0.005mol的MgSO 4，H 4SiO 4的量改成0.1mol，磷酸的量改成0.9mol和NH 4HF 2的量改成0.04mol之外，其他与实施例1相同。
实施例27
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.4mol，FeSO 4﹒H 2O的量改为0.3mol，在制备掺杂的草酸锰时还加入0.1mol的VCl 2和0.2mol的CoSO 4，将Li 2CO 3的量改变为0.485mol，将0.001mol的Mo(SO 4) 3换成0.005mol的MgSO 4，H 4SiO 4的量改成0.08mol，磷酸的量改成0.92mol和NH 4HF 2的量改成0.05mol之外，其他与实施例1相同。
对比例1
制备草酸锰：将1mol的MnSO 4﹒H 2O加至反应釜中，并加入10L去离子水和1mol二水合草酸(以草酸计)。将反应釜加热至80℃，以600rpm的转速搅拌6小时,反应终止(无气泡产生)，得到草酸锰悬浮液。然后过滤所述悬浮液，将滤饼在120℃下烘干，之后进行研磨，得到中值粒径Dv 50为50-200nm的草酸锰颗粒。
制备磷酸锰锂：取1mol上述草酸锰颗粒、0.5mol碳酸锂、含有1mol磷酸的浓度为85％的磷酸水溶液和0.005mol蔗糖加入到20L去离子水中。将混合物转入砂磨机中充分研磨搅拌10小时，得到浆料。将所述浆料转移到喷雾干燥设备中进行喷雾干燥造粒，设定干燥温度为250℃，干燥4小时，得到颗粒。在氮气(90体积％)+氢气(10体积％)保护气氛中，将上述粉料在700℃下烧结10小时，得到碳包覆的LiMnPO 4。
对比例2
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为0.8mol，0.7mol的FeSO 4﹒H 2O换成1.2mol的ZnSO 4，将Li 2CO 3的量改变为0.499mol，将0.001mol的Mo(SO 4) 3换成0.001mol的MgSO 4之外，其他与实施例1相同。
对比例3
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.4mol，FeSO 4﹒H 2O的量改为0.6mol，将Li 2CO 3的量改变为0.534mol，将0.001mol的Mo(SO 4) 3换成0.001mol的MgSO 4，将磷酸的量改成0.88mol，H 4SiO 4的量改成0.12mol，NH 4HF 2的量改成0.025mol之外，其他与实施例1相同。
对比例4
除了在“1)正极活性材料的制备”中，将MnSO 4﹒H 2O的量改为1.2mol，FeSO 4﹒H 2O的量改为0.8mol，将Li 2CO 3的量改变为0.474mol，将0.001mol的Mo(SO 4) 3 换成0.001mol的MgSO 4，将磷酸的量改成0.93mol，H 4SiO 4的量改成0.07mol，NH 4HF 2的量改成0.06mol之外，其他与实施例1相同。
二、正极活性材料性质及电池性能测试方法
1.晶格变化率测量方法
在25℃恒温环境下，将正极活性材料样品置于XRD(型号为Bruker D8 Discover)中，采用1°/分钟对样品进行测试，并对测试数据进行整理分析，参照标准PDF卡片，计算出此时的晶格常数a0、b0、c0和v0(a0,b0和c0表示晶胞各个方面上的长度大小，v0表示晶胞体积，可通过XRD精修结果直接获取)。
采用上述实施例中扣电制备方法，将所述正极活性材料样品制备成扣电，并对上述扣电以0.05C小倍率进行充电，直至电流减小至0.01C。然后将扣电中的正极极片取出，并置于DMC中浸泡8小时。然后烘干，刮粉，并筛选出其中粒径小于500nm的颗粒。取样并按照与上述测试新鲜样品同样的方式计算出其晶格常数v1，将(v0-v1)/v0×100％作为其完全脱嵌锂前后的晶格变化率示于表中。
2.Li/Mn反位缺陷浓度测量方法
将“晶格变化率测量方法”中测试的XRD结果与标准晶体的PDF(Powder Diffraction File)卡片对比，得出Li/Mn反位缺陷浓度。具体而言，将“晶格变化率测量方法”中测试的XRD结果导入通用结构分析系统(GSAS)软件中，自动获得精修结果，其中包含了不同原子的占位情况，通过读取精修结果获得Li/Mn反位缺陷浓度。
3.表面氧价态测量方法
取5g正极活性材料样品按照上述实施例中所述扣电制备方法制备成扣电。对扣电采用0.05C小倍率进行充电，直至电流减小至0.01C。然后将扣电中的正极极片取出，并置于DMC中浸泡8小时。然后烘干，刮粉，并筛选出其中粒径小于500nm的颗粒。将所得颗粒用电子能量损失谱(EELS，所用仪器型号为Talos F200S)进行测量，获取能量损失近边结构(ELNES)，其反映元素的态密度和能级分布情况。根据态密度和能级分布，通过对价带态密度数据进行积分，算出占据的电子数，从而推算出充电后的表面氧的价态。
4.压实密度测量方法
取5g的粉末放于压实专用模具(美国CARVER模具，型号13mm)中,然后将模具放在压实密度仪器上。施加3T的压力，在设备上读出压力下粉末的厚度(卸压后的厚度)，通过ρ＝m/v，计算出压实密度。
5.循环后Mn(以及Mn位掺杂的Fe)溶出量测量方法
将45℃下循环至容量衰减至80％后的全电池采用0.1C倍率进行放电至截止 电压2.0V。然后将电池拆开，取出负极极片，在负极极片上随机取30个单位面积(1540.25mm 2)的圆片，用Agilent ICP-OES730测试电感耦合等离子体发射光谱(ICP)。根据ICP结果计算其中Fe(如果正极活性材料的Mn位掺杂有Fe的话)和Mn的量，从而计算循环后Mn(以及Mn位掺杂的Fe)的溶出量。测试标准依据EPA-6010D-2014。
6.扣式电池初始克容量测量方法
在2.5～4.3V下，将扣式电池按照0.1C充电至4.3V，然后在4.3V下恒压充电至电流小于等于0.05mA，静置5分钟，然后按照0.1C放电至2.0V，此时的放电容量为初始克容量，记为D0。
7.3C充电恒流比测量方法
在25℃恒温环境下，将新鲜全电池静置5min，按照1/3C放电至2.5V。静置5min，按照1/3C充电至4.3V，然后在4.3V下恒压充电至电流小于等于0.05mA。静置5min，记录此时的充电容量为C0。按照1/3C放电至2.5V，静置5min，再按照3C充电至4.3V，静置5分钟，记录此时的充电容量为C1。3C充电恒流比即为C1/C0×100％。
3C充电恒流比越高，说明电池的倍率性能越好。
8.全电池45℃循环性能测试
在45℃的恒温环境下，在2.5～4.3V下，将全电池按照1C充电至4.3V，然后在4.3V下恒压充电至电流小于等于0.05mA。静置5分钟，然后按照1C放电至2.5V，记录此时的放电容量为D0。重复前述充放电循环，直至放电容量降低到D0的80％。记录此时电池经过的循环圈数。
9.全电池60℃胀气测试
在60℃下，存储100％充电状态(SOC)的全电池。在存储前后及过程中测量电芯的开路电压(OCV)和交流内阻(IMP)以监控SOC，并测量电芯的体积。其中在每存储48h后取出全电池，静置1h后测试开路电压(OCV)、内阻(IMP)，并在冷却至室温后用排水法测量电芯体积。排水法即先用表盘数据自动进行单位转换的天平单独测量电芯的重力F 1，然后将电芯完全置于去离子水(密度已知为1g/cm 3)中，测量此时的电芯的重力F 2，电芯受到的浮力F 浮即为F 1-F 2，然后根据阿基米德原理F 浮＝ρ×g×V 排，计算得到电芯体积V＝(F 1-F 2)/(ρ×g)。
由OCV、IMP测试结果来看，本实验过程中直至存储结束，实施例的电池始终保持99％以上的SOC。
存储30天后，测量电芯体积，并计算相对于存储前的电芯体积，存储后的电芯体积增加的百分比。
另外，测量电芯残余容量。在2.5～4.3V下，将全电池按照1C充电至4.3V，然后在4.3V下恒压充电至电流小于等于0.05mA。静置5分钟，记录此时的充电容量为电芯残余容量。
表1中示出实施例1-11和对比例1-4的正极活性材料组成。表2中示出实施例1-11和对比例1-4的正极活性材料或扣电或全电按照上述性能测试方法测得的性能数据。表3示出实施例12-27的正极活性材料组成。表4中示出实施例12-27的正极活性材料或扣电或全电按照上述性能测试方法测得的性能数据。
表1实施例1-11和对比例1-8的正极活性材料组成
  正极活性材料
对比例1 LiMnPO 4
对比例2 Li 0.998Mg 0.001Mn 0.4Zn 0.6P 0.999Si 0.001O 3.999F 0.001
对比例3 Li 1.068Mg 0.001Mn 0.7Fe 0.3P 0.88Si 0.12O 3.95F 0.05
对比例4 Li 0.948Mg 0.001Mn 0.6Fe 0.4P 0.93Si 0.07O 3.88F 0.12
实施例1 Li 0.994Mo 0.001Mn 0.65Fe 0.35P 0.999Si 0.001O 3.999F 0.001
实施例2 Li 0.977Mg 0.001Mn 0.65Fe 0.34Ti 0.01P 0.999N 0.001O 3.999F 0.001
实施例3 Li 0.992W 0.001Mn 0.65Fe 0.35P 0.999S 0.001O 3.999F 0.001
实施例4 Li 0.997Al 0.001Mn 0.65Fe 0.35P 0.999Si 0.001O 3.999Cl 0.001
实施例5 Li 0.993Nb 0.001Mn 0.65Fe 0.345V 0.005P 0.999S 0.001O 3.999F 0.001
实施例6 Li 0.993Nb 0.001Mn 0.65Fe 0.34V 0.005Mg 0.005P 0.999S 0.001O 3.999F 0.001
实施例7 Li 0.993Nb 0.001Mn 0.65Fe 0.34V 0.005Co 0.005P 0.999S 0.001O 3.999F 0.001
实施例8 Li 0.993Nb 0.001Mn 0.65Fe 0.34V 0.005Ni 0.005P 0.999S 0.001O 3.999F 0.001
实施例9 Li 0.991Nb 0.001Mn 0.65Fe 0.349Ti 0.001P 0.999S 0.001O 3.999Cl 0.001
实施例10 Li 0.995Nb 0.001Mn 0.65Fe 0.34V 0.005Mg 0.005P 0.999Si 0.001O 3.999Br 0.001
实施例11 Li 0.998Mg 0.001Mn 0.65Fe 0.345V 0.005P 0.999Si 0.001O 3.999Br 0.001
表2实施例1-11和对比例1-8的正极活性材料或扣电或全电按照上述性能测试方法测得的性能数据
Figure PCTCN2022084859-appb-000015
Figure PCTCN2022084859-appb-000016
表3实施例12-27的正极活性材料组成
  正极活性材料 (1-y):y a：x
实施例12 Li 0.997Mg 0.001Mn 0.68Fe 0.3V 0.02P 0.999N 0.001O 3.999F 0.001 2.13 997
实施例13 Li 0.997Mg 0.001Mn 0.58Fe 0.4V 0.02P 0.999N 0.001O 3.999F 0.001 1.38 997
实施例14 Li 0.997Mg 0.001Mn 0.65Fe 0.3V 0.05P 0.999N 0.001O 3.999F 0.001 1.86 997
实施例15 Li 0.988Mg 0.005Mn 0.6Fe 0.35V 0.05P 0.999S 0.001O 3.999F 0.001 1.50 197.6
实施例16 Li 0.984Mg 0.005Mn 0.6Fe 0.35V 0.05P 0.995S 0.005O 3.999F 0.001 1.50 196.8
实施例17 Li 0.984Mg 0.005Mn 0.6Fe 0.35V 0.05P 0.999S 0.001O 3.995F 0.005 1.50 196.8
实施例18 Li 0.984Mg 0.005Mn 0.65Fe 0.25V 0.05Co 0.05P 0.999S 0.001O 3.995F 0.005 1.86 196.8
实施例19 Li 0.984Mg 0.005Mn 0.65Fe 0.20V 0.05Co 0.10P 0.999S 0.001O 3.995F 0.005 1.86 196.8
实施例20 Li 0.984Mg 0.005Mn 0.75Fe 0.05V 0.05Co 0.15P 0.999S 0.001O 3.995F 0.005 3.00 196.8
实施例21 Li 0.984Mg 0.005Mn 0.65Fe 0.25V 0.05Ni 0.05P 0.999S 0.001O 3.995F 0.005 1.86 196.8
实施例22 Li 0.984Mg 0.005Mn 0.75Fe 0.10V 0.05Ni 0.10P 0.999S 0.001O 3.995F 0.005 3.00 196.8
实施例23 Li 0.984Mg 0.005Mn 0.7Fe 0.15V 0.05Co 0.10P 0.999S 0.001O 3.995F 0.005 2.33 196.8
实施例24 Li 0.984Mg 0.005Mn 0.6Fe 0.25V 0.05Co 0.10P 0.999S 0.001O 3.995F 0.005 1.50 196.8
实施例25 Li 0.984Mg 0.005Mn 0.5Fe 0.35V 0.05Co 0.10P 0.999S 0.001O 3.995F 0.005 1.00 196.8
实施例26 Li 1.01Mg 0.005Mn 0.7Fe 0.15V 0.05Co 0.10P 0.9Si 0.1O 3.92F 0.08 2.33 202
实施例27 Li 0.97Mg 0.005Mn 0.7Fe 0.15V 0.05Co 0.10P 0.92Si 0.08O 3.9F 0.1 2.33 194
表4实施例12-27的正极活性材料或扣电或全电按照上述性能测试方法测得的性能数据
Figure PCTCN2022084859-appb-000017
实施例28-63
按照与实施例18相同的方式制备正极活性材料、扣电和全电，但改变电解液组成，具体如下表5所示。
并且，对实施例28-63的扣电或全电按照上述性能测试方法测得性能数据，如表6所示。
表5电解液的组成
Figure PCTCN2022084859-appb-000018
Figure PCTCN2022084859-appb-000019
Figure PCTCN2022084859-appb-000020
表6实施例28-63的扣电或全电按照上述性能测试方法测得性能数据
Figure PCTCN2022084859-appb-000021
Figure PCTCN2022084859-appb-000022
由上述表2、4、6可见，本申请实施例的各正极活性材料均在循环性能、高温稳定性、克容量和压实密度中的一个甚至全部方面实现了比对比例更优的效果。
由实施例18-20、23-25之间相比，可以看出，在其他元素相同的情况下，(1-y):y在1至4范围内，能够进一步提升二次电池的能量密度和循环性能。
而且，将上述实施例1至29的扣电池中的电解液替换为：采用1mol/L的LiPF 6在体积比1：1：1的碳酸乙烯酯(EC)、碳酸二乙酯(DEC)和碳酸二甲酯(DMC)中的溶液组成的电解液；将全电池的电解液替换为：采用1mol/L的LiPF 6在体积比1：1：1的碳酸乙烯酯(EC)、碳酸二乙酯(DEC)和碳酸二甲酯(DMC)中的溶液组成的电解液，对形成的对比例5至31的扣电池或全电池的循环后Mn和Fe溶出量(ppm)、扣电初始克容量(mAh/g)、3C充电恒流比(％)、45℃容量保持率80％循环圈数、60℃存储电芯膨胀率(％)按照上述方法进行检测，检测结果记录在表7中。
表7
Figure PCTCN2022084859-appb-000023
Figure PCTCN2022084859-appb-000024
根据表2、表4和表7的对比可以看出，本申请的电解液组成可以进一步提高二次电池的能量密度和循环性能。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (21)

  1. 一种二次电池，包括正极极片以及非水电解液，其中，
    所述正极极片包括正极活性材料，所述正极活性材料具有化学式Li aA xMn 1-yB yP 1-zC zO 4-nD n，
    其中，所述A包括选自Zn、Al、Na、K、Mg、Nb、Mo和W组成的组中的一种或多种元素，
    所述B包括选自Ti、V、Zr、Fe、Ni、Mg、Co、Ga、Sn、Sb、Nb和Ge组成的组中的一种或多种元素，
    所述C包括选自B(硼)、S、Si和N组成的组中的一种或多种元素，
    所述D包括选自S、F、Cl和Br组成的组中的一种或多种元素，
    所述a选自0.9至1.1的范围，所述x选自0.001至0.1的范围，所述y选自0.001至0.5的范围，所述z选自0.001至0.1的范围，所述n选自0.001至0.1的范围，并且所述正极活性材料为电中性的；
    所述非水电解液包括第一锂盐和第一添加剂，
    所述第一锂盐包括选自LiN(C mF 2m+1SO 2)(C nF 2n+1SO 2)、Li(FSO 2) 2N组成的组中的一种或多种，m、n表示正整数；
    所述第一添加剂包括式1所示化合物中的一种或多种，
    Figure PCTCN2022084859-appb-100001
    R 1表示经一个或多个R a取代或未取代的C2～C10亚烷基、C2～C10杂亚烷基、C6～C18亚芳基、C2～C18杂亚芳基、C3～C18亚脂环基、C3～C18杂亚脂环基中的任意一种，
    R a包括选自卤原子、-CN、-NCO、-OH、-COOH、-SOOH、-COOR b、C2～C10烷基、C2～C10烯基、C2～C10炔基、C2～C10氧杂烷基中的一种或多种，R b选自C1-C10烷基中的任意一种。
  2. 根据权利要求1所述的二次电池，其中，R 1表示经一个或多个R a取代或未取代的C2～C10亚烷基、C2～C10氧杂亚烷基、C2～C10氮杂亚烷基、亚苯基、亚萘基、亚蒽基、亚环丁基、亚环戊基、亚环己基、亚联苯基、亚甲基二亚苯基中的任意一种，可选地所述R 1表示经一个或多个R a取代或未取代的C2～C6亚烷基、亚苯基、亚萘基、亚蒽基、亚环丁基、亚环戊基、亚环己基、亚联苯基、亚甲基二亚苯基中的任意一种；
    和/或所述R a包括选自卤原子、-CN、C2～C3烷基中的一种或多种；
    和/或所述式1所示化合物中所述R a的个数为0、1、2、3或4个。
  3. 根据权利要求1或2所述的二次电池，其中，所述第一添加剂包括如下化合物中的一种或多种：
    Figure PCTCN2022084859-appb-100002
    Figure PCTCN2022084859-appb-100003
  4. 根据权利要求1-3中任一项所述的二次电池，其中，m、n各自独立地表示1、2或3；
    和/或，所述第一锂盐选自LiN(CF 3SO 2) 2、Li(FSO 2) 2N中的任意一种，所述第一添加剂选自如下化合物中的任意一种：
    Figure PCTCN2022084859-appb-100004
  5. 根据权利要求1-3中任一项所述的二次电池，其中，基于所述非水电解液的总重量，
    所述第一锂盐的含量为W1重量％，W1为0.1至48，可选地为5至20；
    所述第一添加剂的含量为W2重量％，W2为0.01至20，可选地为0.1至10或0.3至5，
    可选地W2/W1定义为M，M为0.001至3，可选地为0.005至0.5。
  6. 根据权利要求1-5中任一项所述的二次电池，其中，所述非水电解液还包括第二锂盐，所述第二锂盐包括选自二氟磷酸锂、二氟二草酸磷酸锂、二氟草酸硼酸锂、双草酸硼酸锂、LiPF 6、LiBF 4中的一种或多种。
  7. 根据权利要求6所述的二次电池，其中，基于所述非水电解液的总重量，所述第二锂盐的含量为W3重量％，W3为0.01至20，可选地为0.1至10或0.3至5。
  8. 根据权利要求7所述的二次电池，其中，(W2+W3)/W1定义为N，N为0.01至5，可选地0.02至1。
  9. 根据权利要求1-8中任一项所述的二次电池，其中，所述非水电解液还包括第二添加剂，所述第二添加剂包括含有不饱和键的环状碳酸酯化合物、卤素取代的饱和环状碳酸酯化合物、硫酸酯化合物、亚硫酸酯化合物、磺酸内酯化合物、二磺酸化合物、腈化合物、芳香化合物、磷腈化合物、环状酸酐化合物、亚磷酸酯化合物、磷酸酯化合物、硼酸酯化合物组成的组中的一种或多种。
  10. 根据权利要求1-9中任一项所述的二次电池，其中，所述非水电解液还包括有机溶剂，
    所述有机溶剂包括环状碳酸酯化合物、链状碳酸酯化合物、羧酸酯化合物中的一种或多种，
    可选地，所述有机溶剂包括碳酸二甲酯、碳酸二乙酯、碳酸二丙酯、碳酸甲乙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸乙烯酯、碳酸丙烯酯、碳酸丁烯酯、γ-丁内酯、甲酸甲酯、甲酸乙酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丁酯、四氢呋喃组成的组中的一种或多种。
  11. 根据权利要求1-10中任一项所述的二次电池，其中，所述A、C和D各自独立地为上述各自范围内的任一种元素，并且所述B为其范围内的至少两种元素；
    可选地，
    所述A为选自Mg和Nb中的任一种元素，和/或，
    所述B为选自Fe、Ti、V、Co和Mg中的至少两种元素，可选地为Fe与选自Ti、V、Co和Mg中的一种以上元素，和/或，
    所述C为S，和/或，
    所述D为F。
  12. 根据权利要求1-11中任一项所述的二次电池，其中，
    所述x选自0.001至0.005的范围；和/或，
    所述y选自0.01至0.5的范围，可选地选自0.25至0.5的范围；和/或，
    所述z选自0.001至0.005的范围；和/或，
    所述n选自0.001至0.005的范围。
  13. 根据权利要求1-12中任一项所述的二次电池，其中，(1-y):y在1至4范围内，可选地在1.5至3范围内，且a:x在9到1100范围内，可选地在190-998范围内。
  14. 根据权利要求1-13中任一项所述的二次电池，其中，所述正极活性材料的晶格变化率为8％以下，可选地为4％以下。
  15. 根据权利要求1-14中任一项所述的二次电池，其中，所述正极活性材料的Li/Mn反位缺陷浓度为2％以下，可选地为0.5％以下。
  16. 根据权利要求1-15中任一项所述的二次电池，其中，所述正极活性材料的表面氧价态为-1.82以下，可选地为-1.89～-1.98。
  17. 根据权利要求1-16中任一项所述的二次电池，其中，所述正极活性材料的在3T下的压实密度为2.0g/cm 3以上，可选地为2.2g/cm 3以上。
  18. 根据权利要求1-17中任一项所述的二次电池，其中，所述正极活性材料的表面包覆有碳。
  19. 一种电池模块，包括二次电池，其中，所述二次电池为权利要求1-18中任一项所述的二次电池。
  20. 一种电池包，包括电池模块，其中，所述电池模块为权利要求19所述的电池模块。
  21. 一种用电装置，包括二次电池、电池模块和电池包中的至少一种，其中，所述二次电池为权利要求1-18任一项所述的二次电池，所述电池模块为权利要求19所述的电池模块，所述电池包为权利要求20所述的电池包。
PCT/CN2022/084859 2022-04-01 2022-04-01 二次电池、电池模块、电池包和用电装置 Ceased WO2023184496A1 (zh)

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