WO2023070988A1 - 电化学装置和包含其的电子装置 - Google Patents

电化学装置和包含其的电子装置 Download PDF

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WO2023070988A1
WO2023070988A1 PCT/CN2022/075970 CN2022075970W WO2023070988A1 WO 2023070988 A1 WO2023070988 A1 WO 2023070988A1 CN 2022075970 W CN2022075970 W CN 2022075970W WO 2023070988 A1 WO2023070988 A1 WO 2023070988A1
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positive electrode
electrode material
electrochemical device
lithium
formula
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French (fr)
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周墨林
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Ningde Amperex Technology Ltd
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Ningde Amperex Technology Ltd
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Priority to EP22884905.5A priority Critical patent/EP4421897A4/en
Priority to CN202280002000.8A priority patent/CN114938688B/zh
Priority to JP2024524756A priority patent/JP7815430B2/ja
Publication of WO2023070988A1 publication Critical patent/WO2023070988A1/zh
Priority to US18/645,907 priority patent/US12438145B2/en
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    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
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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
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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
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
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    • H01M4/362—Composites
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    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
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    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • C—CHEMISTRY; METALLURGY
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    • C01P2002/50—Solid solutions
    • C01P2002/52—Solid solutions containing elements as dopants
    • C01P2002/54—Solid solutions containing elements as dopants one element only
    • C—CHEMISTRY; METALLURGY
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    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
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    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of energy storage, in particular to an electrochemical device and an electronic device containing it, especially a lithium ion battery.
  • lithium-ion energy storage devices When using high-capacity negative electrode materials, such as alloys (silicon, tin, etc.), oxides (silicon oxide, tin oxide) and amorphous carbon negative electrodes, the consumption of active lithium sources will be further aggravated. Therefore, a suitable lithium supplementation method is of great significance to further improve the energy density of lithium-ion energy storage devices.
  • alloys silicon, tin, etc.
  • oxides silicon oxide, tin oxide
  • amorphous carbon negative electrodes a suitable lithium supplementation method is of great significance to further improve the energy density of lithium-ion energy storage devices.
  • the present application solves the problems existing in the prior art to some extent by providing an electrochemical device and an electronic device having improved cycle performance and energy density.
  • the present application provides an electrochemical device, and the electrochemical device includes a positive electrode, a negative electrode and an electrolyte.
  • the positive electrode includes a positive electrode current collector and a positive electrode material layer on at least one surface of the positive electrode current collector.
  • the positive electrode material layer comprises the first positive electrode material shown in formula (I):
  • M includes at least one of Ti, Zr, V or Cr, and A includes at least one of S, N, F, Cl or Br;
  • X includes at least one of Fe, Co, Ni, Ti, Zn, Mg, Al, V, Cr or Zr, and T includes at least one of S, N, F, Cl, or Br;
  • the positive electrode satisfies formula (1):
  • the positive electrode satisfies formula (2): 1.5 ⁇ R ⁇ P/Q ⁇ 10 Formula (2).
  • the mass ratio of the first positive electrode material to the second positive electrode material is 5:1 to 99:1.
  • the content of the first positive electrode material is 80% to 98%.
  • the X-ray diffraction spectrum of the second positive electrode material has a characteristic diffraction peak A in the range of 15° to 16°, and/or has a characteristic diffraction peak B in the range of 18° to 19°, and the characteristic diffraction
  • the ratio I A /IB of the intensity I A of the peak A and the intensity I B of the characteristic diffraction peak B satisfies the formula (3): 0 ⁇ IA / IB ⁇ 0.2 Formula (3).
  • both the characteristic diffraction peak A and the characteristic diffraction peak B are shifted to a low-angle direction, and the shift amplitude is less than 0.5°.
  • the electrolytic solution includes vinylene carbonate, wherein the content of the vinylene carbonate is 0.05% to 5% based on the total mass of the electrolytic solution.
  • the present application provides an electronic device, which includes the electrochemical device according to the embodiment of the present application.
  • the application provides a lithium ion secondary battery containing a positive electrode lithium supplement material.
  • the second positive electrode material used in this application has a low surface free lithium content and excellent processability.
  • this material has a higher specific capacity, and can release a large amount of lithium ions to supplement active lithium when it is first charged. Combining it with the first positive electrode material can effectively improve the energy density and cycle of the battery. life.
  • the present application can significantly improve the cycle life and energy density of the lithium-ion secondary battery by comprehensively designing the sheet resistance, compaction density and areal density of the positive electrode.
  • by adding vinylene carbonate additive to the electrolyte a more uniform and dense SEI film is formed on the negative electrode, which suppresses the continuous loss of active lithium and further improves the cycle life of the lithium-ion secondary battery.
  • FIG. 1 shows the XRD patterns of the second positive electrode material in Example 1 before and after the first cycle of charging.
  • FIG. 2 shows a partially enlarged view of FIG. 1 .
  • a list of items linked by the terms “one of”, “one of”, “one of” or other similar terms may mean that any of the listed items one.
  • the phrase “one of A and B” means only A or only B.
  • the phrase “one of A, B, and C” means only A; only B; or only C.
  • Item A may contain a single element or multiple elements.
  • Item B may contain a single element or multiple elements.
  • Item C may contain a single element or multiple elements.
  • a list of items linked by the terms “at least one of”, “at least one of”, “at least one of” or other similar terms may mean that the listed items any combination of .
  • the phrase “at least one of A and B” means only A; only B; or A and B.
  • the phrase “at least one of A, B, and C” means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C.
  • Item A may contain a single element or multiple elements.
  • Item B may contain a single element or multiple elements.
  • Item C may contain a single element or multiple elements.
  • the application provides an electrochemical device, which includes a positive electrode, a negative electrode, and an electrolyte.
  • the positive electrode comprises a positive electrode current collector and a positive electrode material layer positioned on at least one surface of the positive electrode current collector, and the positive electrode material layer includes a first positive electrode material represented by formula (I):
  • M includes at least one of Ti, Zr, V or Cr, and A includes at least one of S, N, F, Cl or Br;
  • X includes at least one of Fe, Co, Ni, Ti, Zn, Mg, Al, V, Cr or Zr, and T includes at least one of S, N, F, Cl, or Br;
  • the positive electrode satisfies formula (1):
  • the calculation of R ⁇ P/Q only involves numerical calculation.
  • the resistance R of the positive electrode is 0.5 ⁇
  • the compacted density P is 2.2g/cm 3
  • the single-sided density Q of the positive electrode is 0.3g /1540.25mm 2
  • R ⁇ P/Q 3.7.
  • the resistance R of the positive electrode is the resistance value measured by the DC two-probe method, wherein the contact area between the probes and the positive electrode is 49 ⁇ mm 2 .
  • the diameter of the conductive terminals is 14mm, and the applied pressure is 15MPa to 27MPa.
  • the positive electrode resistance tester is Hiji BT23562 internal resistance tester.
  • the volume v of the positive electrode material layer can be the product of the area Ar of the positive electrode material layer and the thickness of the positive electrode material layer.
  • the positive electrode material layer is located on one surface of the positive electrode current collector. In some embodiments, the positive electrode material layer is located on both surfaces of the positive electrode current collector.
  • the first positive electrode material includes LiFePO 4 , LiFe 0.5 Mn 0.5 PO 4 , Li 0.9 Fe 0.5 Mn 0.45 Ti 0.05 PO 4 , Li 0.9 Fe 0.5 Mn 0.45 Ti 0.04 Zr 0.01 PO 4 or Li 0.95 FePO At least one of 3.95 F 0.05 .
  • the second positive electrode material includes at least one of LiMnO 2 , LiMn 0.9 Ni 0.1 O 2 , LiMn 0.9 Ni 0.05 Cr 0.05 O 2 , Li 0.95 MnO 1.95 F 0.05 or Li 0.95 MnO 1.9 S 0.05 F 0.05 one.
  • 1.5 ⁇ R ⁇ P/Q In some embodiments, 1.5 ⁇ R ⁇ P/Q ⁇ 10. In some embodiments, the value of R ⁇ P/Q is 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, or a range of any two of these values.
  • R ⁇ 3.5 ⁇ . In some embodiments, R is 0.2 ⁇ , 0.5 ⁇ , 1 ⁇ , 1.2 ⁇ , 1.5 ⁇ , 1.8 ⁇ , 2.0 ⁇ , 2.2 ⁇ , 2.5 ⁇ , 3.0 ⁇ , 3.2 ⁇ , 3.5 ⁇ or a combination of any two of these values range. When R is in the above range, it is beneficial to improve the cycle performance and rate performance of the lithium ion secondary battery.
  • 1.6 g/cm 3 ⁇ P ⁇ 2.6 g/cm 3 .
  • P is 1.6 g/cm 3 , 1.8 g/cm 3 , 2.0 g/cm 3 , 2.2 g/cm 3 , 2.4 g/cm 3 , 2.6 g/cm 3 , or any two of these values range of composition.
  • P is in the above range, it is beneficial to the migration of electrons and ions in the positive electrode, thereby improving the cycle performance of the lithium ion secondary battery.
  • 0.16g/1540.25mm 2 ⁇ Q ⁇ 0.45g/1540.25mm 2 .
  • Q is 0.16g/1540.25mm 2 , 0.18g/1540.25mm 2 , 0.2g/1540.25mm 2 , 0.25g/1540.25mm 2 , 0.28g/1540.25mm 2 , 0.30g/1540.25mm 2 , 0.34g/1540.25mm 2 , 0.36g/1540.25mm 2 , 0.38g/1540.25mm 2 , 0.40g/1540.25mm 2 , 0.42g/1540.25mm 2 , 0.45g/1540.25mm 2 or any two of these values scope.
  • Q is in the above range, the cycle performance and rate performance of the lithium-ion secondary battery can be improved on the premise of ensuring the charge and discharge capacity.
  • the mass ratio of the first positive electrode material to the second positive electrode material is 5:1 to 99:1. In some embodiments, the mass ratio of the first positive electrode material to the second positive electrode material is 5:1, 9:1, 10:1, 15:1, 20:1, 25:1, 30:1 , 35:1, 40:1, 45:1, 50:1, 55:1, 60:1, 65:1, 70:1, 75:1, 80:1, 85:1, 90:1, 95 :1, 99:1, or a range consisting of any two of these values. When the mass ratio of the first positive electrode material to the second positive electrode material is within the above range, the positive electrode includes a higher content of the first positive electrode material, so that the positive electrode has higher structural stability and can reduce the damage caused by the structural damage of the positive electrode material. Capacity loss and impedance increase, thereby maintaining the cycle stability and kinetic performance of Li-ion batteries.
  • the content of the first positive electrode material is 80% to 98%. In some embodiments, based on the total mass of the positive electrode material layer, the content of the first positive electrode material is 80%, 82%, 84%, 85%, 88%, 90%, 92%, 94%, 96% %, 98%, or a range consisting of any two of these values.
  • the X-ray diffraction spectrum of the second positive electrode material has a characteristic diffraction peak A in the range of 15° to 16°, and/or has a characteristic diffraction peak B in the range of 18° to 19°, and the characteristic diffraction
  • the ratio I A /IB of the intensity I A of the peak A and the intensity I B of the characteristic diffraction peak B satisfies the formula (3): 0 ⁇ IA / IB ⁇ 0.2 Formula (3).
  • the value of I A / IB is 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, or a range consisting of any two of these values.
  • both the characteristic diffraction peak A and the characteristic diffraction peak B are shifted to a low-angle direction, and the shift amplitude is less than 0.5°.
  • the magnitude of the offset is 0.1°, 0.2°, 0.3°, 0.4°, 0.45°, or a range consisting of any two of these values.
  • the positive electrode material layer includes a conductive agent.
  • the conductive agent includes at least one of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, or carbon nanofibers.
  • the content of the conductive agent is 0.5 to 20%. In some embodiments, based on the total mass of the positive electrode material layer, the content of the conductive agent is 0.5%, 1%, 5%, 8%, 10%, 12%, 14%, 16%, 18%, 20% or a range combining any two of these values.
  • the cathode material layer includes a binder.
  • the binder includes styrene-butadiene rubber (SBR), water-based acrylic resin, carboxymethyl cellulose (CMC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), poly At least one of vinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA), or polyvinyl alcohol (PVA).
  • SBR styrene-butadiene rubber
  • CMC carboxymethyl cellulose
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • PVB poly At least one of vinyl butyral
  • EVA ethylene-vinyl acetate copolymer
  • PVA polyvinyl alcohol
  • the content of the binder is 0.1 to 2.5%. In some embodiments, based on the total mass of the positive electrode material layer, the content of the binder is 0.1%, 0.2%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%. , 2.5%, or a range consisting of any two of these values.
  • the positive current collector includes a metal foil or a porous metal plate. In some embodiments, the positive electrode current collector includes a foil or a porous plate of a metal such as aluminum, copper, nickel, titanium or silver or an alloy thereof. In some embodiments, the positive electrode current collector includes at least one of copper foil or aluminum foil.
  • the positive electrode collector has a thickness of 5 ⁇ m to 20 ⁇ m. In some embodiments, the thickness of the positive current collector is 5 ⁇ m, 8 ⁇ m, 10 ⁇ m, 12 ⁇ m, 15 ⁇ m, 18 ⁇ m, 20 ⁇ m or a range consisting of any two of these values.
  • the positive electrode can be obtained by mixing the positive electrode active material, the conductive agent and the binder in a solvent to prepare an active material composition, and coating the active material composition on the current collector superior.
  • the solvent may include N-methylpyrrolidone and the like, but is not limited thereto.
  • the positive electrode of the present application can fully exert the synergistic effect between the first positive electrode material and the second positive electrode material.
  • the second positive electrode material has the characteristics of high first-time charge specific capacity and low first-efficiency, which effectively compensates for the loss of active lithium caused by the formation of SEI, and there are enough lithium ions back into the first positive electrode during the first discharge.
  • the energy density of the battery is effectively improved.
  • the structure of the first positive electrode material selected in this application is stable, the volume change is small during the charging and discharging process, and the cycle stability is better.
  • the energy density, rate performance, and cycle life of lithium-ion secondary batteries can be further improved. Therefore, by adopting the positive electrode of the present application, the lithium-ion secondary battery can obtain high energy density, good rate performance and long cycle life.
  • the sheet resistance, compaction density, and single-surface density of the positive electrode are key parameters in the design and fabrication of lithium-ion secondary batteries. If the sheet resistance of the positive electrode is too large, the cycle performance and rate performance of the lithium-ion secondary battery will be deteriorated. If the compaction density is too large or too small, the cycle performance and rate performance of the battery will be deteriorated. If the density of one side of the positive electrode is too high, the cycle life of the battery will be reduced, and it will also affect the penetration of the electrolyte, thereby affecting the rate performance of the battery, especially reducing the discharge capacity of the battery at a high rate. However, the single surface density of the positive electrode is too small, which means that the length of the current collector and separator increases under the same battery capacity, which increases the ohmic internal resistance of the battery.
  • the positive electrode includes the first positive electrode material and the second positive electrode material at the same time
  • the comprehensive design of parameters such as the sheet resistance, compaction density, and single-sided surface density of the positive electrode
  • the electric capacity of the lithium-ion secondary battery can be improved.
  • the chemical properties met the expected results.
  • the electrolytic solution used in the electrochemical device of the present application includes an electrolyte and a solvent for dissolving the electrolyte.
  • the electrolyte solution includes an additive, and the additive includes vinylene carbonate, wherein the content of the vinylene carbonate is 0.05% to 5% based on the total mass of the electrolyte solution.
  • the content of the vinylene carbonate is 0.05%, 1%, 2%, 3%, 4%, 5%, or any two of these values.
  • the cycle performance and energy density of the lithium-ion secondary battery can be further improved.
  • the electrolyte solution may also include other additives, which may be any additives that can be used as lithium-ion secondary batteries, which are not specifically limited in this application and can be selected according to actual needs.
  • other additives include ethylene carbonate (VEC), succinonitrile (SN), adiponitrile (AND), 1,3-propene sultone (PST), sulfonate cyclic At least one of quaternary ammonium salt, tris(trimethylsilyl) phosphate (TMSP) or tris(trimethylsilyl) borate (TMSB).
  • the electrolyte solution further comprises any non-aqueous solvent that can serve as a solvent for the electrolyte solution.
  • the non-aqueous solvent includes, but is not limited to, one or more of the following: cyclic carbonate, chain carbonate, cyclic carboxylate, chain carboxylate, cyclic Ethers, chain ethers, phosphorus-containing organic solvents, sulfur-containing organic solvents, and aromatic fluorinated solvents.
  • the non-aqueous solvent includes ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), Dipropyl Carbonate (DPC), Methyl Propyl Carbonate (MPC), Ethyl Propyl Carbonate (EPC), Butylene Carbonate (BC), Fluoroethylene Carbonate (FEC), Methyl Formate (MF), Methyl Acetate Ester (MA), Ethyl Acetate (EA), Propyl Acetate (PA), Methyl Propionate (MP), Ethyl Propionate (EP), Propyl Propionate (PP), Methyl Butyrate (MB) , ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS) or diethyl
  • EC
  • the electrolyte is not particularly limited.
  • the electrolyte includes a lithium salt.
  • electrolytes may include, but are not limited to, lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), bisfluorosulfonimide Lithium (LiFSI), lithium bistrifluoromethanesulfonyl imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium difluorooxalate borate (LiBOB), lithium difluorophosphate ( LiPO 2 F 2 ), lithium difluorodifluorooxalate phosphate (LiDFOP) and lithium tetrafluor
  • the content of the electrolyte is not particularly limited as long as the effect of the present application is not impaired.
  • the total molar concentration of lithium in the electrolyte is greater than 0.3 mol/L, greater than 0.4 mol/L or greater than 0.5 mol/L.
  • the total molar concentration of lithium in the electrolyte is less than 3 mol/L, less than 2.5 mol/L or less than 2.0 mol/L.
  • the total molar concentration of lithium in the electrolyte is within the range formed by any two values above. When the electrolyte concentration is within the above range, the lithium as charged particles will not be too small, and the viscosity can be kept in an appropriate range, so it is easy to ensure good electrical conductivity.
  • the negative electrode includes a negative electrode current collector and a negative electrode active material layer on one or both surfaces of the negative electrode current collector.
  • the negative electrode active material layer includes a negative electrode active material.
  • the negative electrode active material layer may be one or more layers, and each layer of the multilayer negative electrode active material may contain the same or different negative electrode active materials.
  • the negative active material is any material capable of reversibly intercalating and deintercalating metal ions such as lithium ions.
  • the chargeable capacity of the negative active material is greater than the discharge capacity of the negative active material, so as to prevent unintentional precipitation of lithium metal on the negative electrode during charging.
  • examples of the negative electrode current collector include, but are not limited to, metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel. In some embodiments, the negative current collector is copper.
  • the form of the negative electrode current collector may include, but not limited to, metal foil, metal cylinder, metal strip, metal plate, metal film, expanded metal, stamped metal, foamed metal, etc.
  • the negative electrode current collector is a metal film.
  • the negative electrode current collector is copper foil.
  • the negative electrode current collector is a rolled copper foil based on a rolling method or an electrolytic copper foil based on an electrolytic method.
  • the thickness of the negative electrode current collector is greater than 1 ⁇ m or greater than 5 ⁇ m. In some embodiments, the thickness of the negative electrode current collector is less than 100 ⁇ m or less than 50 ⁇ m. In some embodiments, the thickness of the negative electrode current collector is within the range formed by any two values above.
  • the negative electrode active material is not particularly limited as long as it can reversibly store and release lithium ions.
  • Examples of negative electrode active materials may include, but are not limited to, carbon materials such as natural graphite and artificial graphite; metals such as silicon (Si) and tin (Sn); or oxides of metal elements such as Si and Sn.
  • the negative electrode active materials can be used alone or in combination.
  • the negative active material layer may further include a negative binder.
  • the negative electrode binder can improve the combination of the negative electrode active material particles and the combination of the negative electrode active material and the current collector.
  • the type of negative electrode binder is not particularly limited, as long as it is a material stable to the electrolyte solution or the solvent used in electrode production.
  • the negative binder includes a resin binder. Examples of resin binders include, but are not limited to, fluororesins, polyacrylonitrile (PAN), polyimide resins, acrylic resins, polyolefin resins, and the like.
  • the negative electrode binder When using a water-based solvent to prepare the negative electrode mixture slurry, the negative electrode binder includes, but is not limited to, carboxymethyl cellulose (CMC) or its salt, styrene-butadiene rubber (SBR), polyacrylic acid (PAA) or Its salt, polyvinyl alcohol, etc.
  • CMC carboxymethyl cellulose
  • SBR styrene-butadiene rubber
  • PAA polyacrylic acid
  • Its salt polyvinyl alcohol, etc.
  • the negative electrode can be prepared by the following method: coating the negative electrode mixture slurry containing the negative electrode active material, resin binder, etc. on the negative electrode current collector, after drying, performing calendering to form the negative electrode on both sides of the negative electrode current collector active material layer, and thus a negative electrode can be obtained.
  • a separator is usually provided between the positive electrode and the negative electrode.
  • the electrolytic solution of the present application is usually used by permeating the separator.
  • the material and shape of the separator are not particularly limited as long as the effect of the present application is not significantly impaired.
  • the separator can be resin, glass fiber, inorganic matter, etc. formed by materials that are stable to the electrolyte of the present application.
  • the separator includes a porous sheet or a non-woven fabric-like substance with excellent liquid retention properties.
  • the material of the resin or fiberglass separator may include, but are not limited to, polyolefin, aramid, polytetrafluoroethylene, polyethersulfone, and the like.
  • the polyolefin is polyethylene or polypropylene.
  • the polyolefin is polypropylene.
  • the materials for the above separators may be used alone or in any combination.
  • the isolation film can also be a material formed by laminating the above materials, examples of which include, but not limited to, a three-layer isolation film formed by laminating polypropylene, polyethylene, and polypropylene in this order.
  • Examples of materials of inorganic substances may include, but are not limited to, oxides such as aluminum oxide and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, sulfates (eg, barium sulfate, calcium sulfate, etc.).
  • Inorganic forms may include, but are not limited to, granular or fibrous.
  • the form of the separator may be in the form of a film, examples of which include, but are not limited to, non-woven fabrics, woven fabrics, microporous films, and the like.
  • the pore diameter of the isolation membrane is 0.01 ⁇ m to 1 ⁇ m, and the thickness is 5 ⁇ m to 50 ⁇ m.
  • the following separator can also be used: a separator formed by forming a composite porous layer containing the above-mentioned inorganic particles on the surface of the positive electrode and/or negative electrode using a resin-based binder,
  • a separator is formed by using fluororesin as a binder to form porous layers on both sides of the positive electrode with 90% of the alumina particles having a particle size of less than 1 ⁇ m.
  • the thickness of the separator is arbitrary. In some embodiments, the thickness of the isolation film is greater than 1 ⁇ m, greater than 5 ⁇ m, or greater than 8 ⁇ m. In some embodiments, the thickness of the isolation film is less than 50 ⁇ m, less than 40 ⁇ m or less than 30 ⁇ m. In some embodiments, the thickness of the isolation film is within the range formed by any two values above. When the thickness of the separator is within the above range, insulation and mechanical strength can be ensured, and rate characteristics and energy density of the electrochemical device can be ensured.
  • the porosity of the separator is arbitrary.
  • the isolation membrane has a porosity greater than 10%, greater than 15%, or greater than 20%.
  • the separator has a porosity of less than 60%, less than 50%, or less than 45%.
  • the porosity of the isolation membrane is within the range formed by any two values above. When the porosity of the separator is within the above range, insulation and mechanical strength can be ensured, and membrane resistance can be suppressed, so that the electrochemical device has good safety characteristics.
  • the average pore diameter of the separator is also arbitrary. In some embodiments, the average pore size of the isolation membrane is less than 0.5 ⁇ m or less than 0.2 ⁇ m. In some embodiments, the average pore size of the isolation membrane is greater than 0.05 ⁇ m. In some embodiments, the average pore diameter of the isolation membrane is within the range formed by any two values above. When the average pore diameter of the separator exceeds the above-mentioned range, short circuits are likely to occur. When the average pore diameter of the separator is within the above range, the electrochemical device has good safety characteristics.
  • the electrochemical device of the present application includes any device that undergoes an electrochemical reaction, and its specific examples include all kinds of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors.
  • the electrochemical device is a lithium secondary battery, including a lithium metal secondary battery or a lithium ion secondary battery.
  • the present application further provides an electronic device, which includes the electrochemical device according to the present application.
  • the application of the electrochemical device of the present application is not particularly limited, and it can be used in any electronic device known in the prior art.
  • the electrochemical device of the present application can be used in, but not limited to, notebook computers, pen-based computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, portable printers, head-worn Stereo headphones, VCRs, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, motorcycles, power assist Bicycles, bicycles, lighting equipment, toys, game consoles, clocks, electric tools, flashlights, cameras, large household storage batteries and lithium-ion capacitors, etc.
  • the lithium ion battery is taken as an example below and the preparation of the lithium ion battery is described in conjunction with specific examples. Those skilled in the art will understand that the preparation method described in this application is only an example, and any other suitable preparation methods are described in this application. within range.
  • Negative electrode active material artificial graphite, thickener sodium carboxymethyl cellulose (CMC), binder (SBR) and conductive carbon black are mixed according to mass ratio 95.7: 1.0: 1.8: 1.5, add solvent deionized water, in The negative electrode slurry is obtained under the action of a vacuum mixer; the negative electrode slurry is evenly coated on the copper foil of the negative electrode current collector. Afterwards, it was transferred to an oven for drying at a temperature of 120°C, and then subjected to cold pressing, cutting, and welding of tabs to obtain a negative electrode.
  • the first positive electrode material LiFePO 4 the second positive electrode material LiMnO 2 , binder PVDF and conductive carbon black, wherein the mass ratio of LiFePO 4 , LiMnO 2 , PVDF and conductive carbon black is 90.4:6.0:2.1:1.5
  • NMP solvent N-methylpyrrolidone
  • the positive electrode slurry was uniformly coated on the aluminum foil of the positive electrode current collector, and then transferred to an oven for drying at a drying temperature of 120°C. After cold pressing, cutting and welding the tabs, the positive electrode is obtained.
  • the content of the first positive electrode material LiFePO 4 is 90.4%
  • the content of the second positive electrode material LiMnO 2 is 6.0%.
  • Ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) were uniformly mixed in a volume ratio of 1:1:1 to obtain an organic solvent.
  • a polyethylene porous membrane with alumina coating was used as the separator, with a thickness of 9 ⁇ m.
  • the electrolyte solution is poured from the liquid injection port, packaged, and then the lithium-ion battery is produced through processes such as formation and capacity.
  • Embodiments 2 to 16 are identical to Embodiments 2 to 16 :
  • Example 2 The difference between Examples 2 to 16 and Example 1 lies in the type of positive electrode material and related performance parameters and the content of additives in the electrolyte, see Table 1 for details.
  • Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the positive electrode material in Comparative Example 1 only contains LiFePO 4 .
  • Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the positive electrode material in Comparative Example 2 only contains LiMnO 2 .
  • Comparative Examples 3 to 4 The difference between Comparative Examples 3 to 4 and Example 1 is that the mass ratio of the first positive electrode material and the second positive electrode material in the positive electrode is different, see Table 1 for details.
  • Comparative Examples 5 to 6 and Example 1 lies in the difference in sheet resistance, compaction density and single surface density of the positive electrode, see Table 1 for details.
  • Comparative Examples 7 to 8 The difference between Comparative Examples 7 to 8 and Example 1 is that the mass percentage of vinylene carbonate in the electrolyte is different, see Table 1 for details.
  • Test the diaphragm resistance of the positive electrode with Hiji BT3562 resistance tester includes: clamp the positive electrode between the two conductive terminals of the internal resistance tester, and apply pressure to fix it, and test the resistance R of the positive electrode.
  • the resistance R of the conductive terminal The diameter is 14mm
  • the applied pressure is 15MPa to 27MPa
  • the sampling time ranges from 5s to 17s.
  • the lithium-ion secondary battery was charged to 4.2V at a constant current rate of 0.5C, and then charged at a constant voltage until the current was less than or equal to 0.05C, and then discharged to 2.5V at a rate of 0.5C, and the 0.5C rate was recorded. discharge capacity.
  • Lithium-ion secondary battery 2C rate discharge capacity retention rate (%) 2C rate discharge capacity/0.5C rate discharge capacity ⁇ 100%.
  • Table 1 shows the composition and related performance parameters of the positive electrodes in Comparative Examples 1 to 8 and Examples 1 to 16, as well as the types and contents of additives in the electrolyte.
  • the contents of the first and second positive electrode materials are calculated based on the total mass of the positive electrode material layer, and the content of vinylene carbonate in the electrolyte is calculated based on the total mass of the electrolyte.
  • Table 2 shows the high-temperature cycle performance, rate performance and energy density of the lithium-ion secondary batteries in Comparative Examples 1-8 and Examples 1-16.
  • the lithium ion battery in which the positive electrode only contains the first positive electrode material or the second positive electrode material has a significantly improved high temperature. cycle performance and energy density, while the rate performance did not change significantly. It can be seen that the joint use of the first positive electrode material and the second positive electrode material will produce a synergistic effect. Without being bound by theory, the above-mentioned synergistic effect may have the following reasons: First, the second positive electrode material used in this application has very little free lithium on the surface, and when it is added to the positive electrode, the resulting slurry has good stability and is easy to process.
  • the second positive electrode material used in this application has a high initial charging specific capacity and low initial efficiency, which can better compensate for the loss of active lithium caused by the formation of SEI, and more lithium ions are back-intercalated into the second positive electrode material during discharge.
  • the energy density of the lithium-ion secondary battery is effectively improved; and in the third aspect, the structure of the first positive electrode material is stable and the cycle performance is good.
  • references to “some embodiments”, “partial embodiments”, “one embodiment”, “another example”, “example”, “specific example” or “partial example” in the entire specification mean that At least one embodiment or example in this application includes a specific feature, structure, material or characteristic described in the embodiment or example.
  • descriptions that appear throughout the specification such as: “in some embodiments”, “in an embodiment”, “in one embodiment”, “in another example”, “in an example In”, “in a particular example” or “example”, they are not necessarily referring to the same embodiment or example in this application.
  • the particular features, structures, materials, or characteristics herein may be combined in any suitable manner in one or more embodiments or examples.

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Abstract

本申请涉及电化学装置和包含其的电子装置。本申请的电化学装置包括正极、负极、隔离膜和电解液。其中正极包含第一正极材料和第二正极材料，第一正极材料具有较好的循环稳定性和较高的首次库仑效率，第二正极材料具有较高的首次充电比容量和较低的首次库仑效率，可以补充因生成SEI造成的活性锂损失。本申请提供的电化学装置具有能量密度高、倍率性能好、循环寿命长的优点。

Description

电化学装置和包含其的电子装置 技术领域
本申请涉及储能领域，具体涉及一种电化学装置和包含其的电子装置，特别是锂离子电池。
背景技术
近年来，随着电池产业化规模的不断扩张及相关技术的发展，锂离子电池的能量密度受到越来越多的关注和挑战。锂离子二次电池在首次充放电过程中，负极表面会形成固态电解质界面(SEI)，造成不可逆容量损失，降低锂离子储能器件的能量密度。在使用石墨负极的锂离子储能器件中，首次循环会消耗大约10％的活性锂源。当采用高比容量的负极材料，如合金类(硅、锡等)，氧化物类(氧化硅、氧化锡)和无定形碳负极时，活性锂源的消耗将进一步加剧。因此，合适的补锂方法对进一步提升锂离子储能器件的能量密度具有重要的意义。
发明内容
本申请通过提供一种具有提高的循环性能和能量密度的电化学装置和电子装置，以在某种程度上解决存在于现有技术的问题。
在一实施例中，本申请提供了一种电化学装置，所述电化学装置包括正极、负极和电解液。所述正极包含正极集流体和位于所述正极集流体的至少一个表面上的正极材料层。所述正极材料层包括式(I)所示的第一正极材料：
Li 1+xFe yMn zM 1-y-zPO 4-tA t           式(I)，
其中，-0.1＜x＜0.1，0＜y≤1，0≤z≤1，0＜y+z≤1，0≤t＜0.2，M包括Ti、Zr、V或Cr中的至少一种，且A包括S，N，F，Cl或Br中的至少一种；和
式(II)所示的第二正极材料：
Li 1+rMn 1-pX pO 2-sT s                          式(II)，
其中，-0.1＜r＜0.2，0≤p＜0.2，0≤s＜0.2，X包括Fe、Co、Ni、Ti、Zn、Mg、Al、V、Cr或Zr中的至少一种，且T包括S、N、F、Cl或Br中的至少一种；并且
所述正极满足式(1)：
0.5≤R×P/Q≤16    式(1)，
其中，R是所述正极的电阻，单位是Ω；P是所述正极的压实密度，单位为g/cm 3；且Q是所述正极的单面面密度，单位为g/1540.25mm 2。
在一些实施例中，所述正极满足式(2)：1.5≤R×P/Q≤10      式(2)。
在一些实施例中，R≤3.5Ω。
在一些实施例中，1.6g/cm 3＜P＜2.6g/cm 3。
在一些实施例中，0.16g/1540.25mm 2＜Q＜0.45g/1540.25mm 2。
在一些实施例中，所述第一正极材料和所述第二正极材料的质量比为5∶1至99∶1。
在一些实施例中，基于所述正极材料层的总质量，所述第一正极材料的含量为80％至98％。
在一些实施例中，所述第二正极材料的X射线衍射谱在15°至16°范围内具有特征衍射峰A，和/或在18°至19°范围内具有特征衍射峰B，特征衍射峰A的强度I A和特征衍射峰B的强度I B的比值I A/I B满足式(3)：0＜I A/I B≤0.2    式(3)。
在一些实施例中，所述第二正极材料在首圈充电后的X射线衍射谱中，特征衍射峰A和特征衍射峰B均向低角度方向偏移，偏移幅度＜0.5°。
在一些实施例中，所述电解液包含碳酸亚乙烯酯，其中基于所述电解液的总质量，所述碳酸亚乙烯酯的含量为0.05％至5％。
在另一实施例中，本申请提供一种电子装置，其包括根据本申请的实施例所述的电化学装置。
本申请提供了一种含有正极补锂材料的锂离子二次电池。一方面，本申请所采用的第二正极材料的表面游离锂含量低，加工性能优良。此外，相比于第一正极材料，该材料的比容量高，在首次充电时可脱出大量的锂离子来补充活性锂，将其与第一正极材料组合，可有效提升电池的能量密度和循环寿命。第二方面，本申请通过对正极的膜片电阻、压实密度和面密度进行综合设计，能够明显提升锂离子二次电池的循环寿命和能量密度。第三方面，通过在电解液中添加碳酸亚乙烯酯添加剂，使得负极形成了更加均匀致密的SEI膜，抑制了活性锂的持续损失，更进一步提升了锂离子二次电池的循环寿命。
本申请的额外层面及优点将部分地在后续说明中描述和显示，或是经由本申请实施 例的实施而阐释。
附图说明
图1示出了实施例1中的第二正极材料在首圈充电前后的XRD图谱。
图2示出了图1的局部放大图。
具体实施方式
本申请的实施例将会被详细的描示在下文中。本申请的实施例不应该被解释为对本申请的限制。
另外，有时在本文中以范围格式呈现量、比率和其它数值。应理解，此类范围格式是用于便利及简洁起见，且应灵活地理解，不仅包含明确地指定为范围限制的数值，而且包含涵盖于所述范围内的所有个别数值或子范围，如同明确地指定每一数值及子范围一般。
在具体实施方式及权利要求书中，由术语“中的一者”、“中的一个”、“中的一种”或其他相似术语所连接的项目的列表可意味着所列项目中的任一者。例如，如果列出项目A及B，那么短语“A及B中的一者”意味着仅A或仅B。在另一实例中，如果列出项目A、B及C，那么短语“A、B及C中的一者”意味着仅A；仅B；或仅C。项目A可包含单个元件或多个元件。项目B可包含单个元件或多个元件。项目C可包含单个元件或多个元件。
在具体实施方式及权利要求书中，由术语“中的至少一者”、“中的至少一个”、“中的至少一种”或其他相似术语所连接的项目的列表可意味着所列项目的任何组合。例如，如果列出项目A及B，那么短语“A及B中的至少一者”意味着仅A；仅B；或A及B。在另一实例中，如果列出项目A、B及C，那么短语“A、B及C中的至少一者”意味着仅A；或仅B；仅C；A及B(排除C)；A及C(排除B)；B及C(排除A)；或A、B及C的全部。项目A可包含单个元件或多个元件。项目B可包含单个元件或多个元件。项目C可包含单个元件或多个元件。
一、电化学装置
在一些实施例中，本申请提供了一种电化学装置，所述电化学装置包括正极、负极和 电解液。
1、正极
在一些实施例中，所述正极包含正极集流体和位于所述正极集流体的至少一个表面上的正极材料层，所述正极材料层包括式(I)所示的第一正极材料：
Li 1+xFe yMn zM 1-y-zPO 4-tA t                   式(I)，
其中，-0.1＜x＜0.1，0＜y≤1，0≤z≤1，0＜y+z≤1，0≤t＜0.2，M包括Ti、Zr、V或Cr中的至少一种，且A包括S，N，F，Cl或Br中的至少一种；和
式(II)所示的第二正极材料：
Li 1+rMn 1-pX pO 2-sT s                        式(II)，
其中，-0.1＜r＜0.2，0≤p＜0.2，0≤s＜0.2，X包括Fe、Co、Ni、Ti、Zn、Mg、Al、V、Cr或Zr中的至少一种，且T包括S、N、F、Cl或Br中的至少一种；并且
所述正极满足式(1)：
0.5≤R×P/Q≤16    式(1)，
其中，R是所述正极的电阻，单位是Ω；P是所述正极的压实密度，单位为g/cm 3；且Q是所述正极的单面面密度，单位为g/1540.25mm 2。
在本文中，R·P/Q的计算仅涉及数值的计算，举例来说，正极的电阻R为0.5Ω，压实密度P为2.2g/cm 3，正极的单面面密度Q为0.3g/1540.25mm 2，则R·P/Q＝3.7。
正极的电阻R为采用直流两探针法所测得的电阻值，其中探针与正极的接触面积为49πmm 2。作为一个示例，将正极的上下侧夹持于极片电阻测试仪的两个导电端子之间，并施加压力以固定，导电端子的直径为14mm，施加压力为15MPa至27MPa。正极电阻测试仪为日置BT23562型内阻测试仪。
正极的压实密度可以通过公式P＝m/v计算得出，式中m为正极材料层的重量，单位是g；v是正极材料层的体积，单位为cm 3。其中正极材料层的体积v可以是正极材料层的面积A r与正极材料层的厚度的乘积。
正极的单面面密度Q可以通过公式Q＝1540.25m/A r计算得出，式中m是正极材料层的重量，单位为g；A r是正极材料层的面积，单位为mm 2。
在一些实施例中，所述正极材料层位于所述正极集流体的一个表面上。在一些实施例中， 所述正极材料层位于所述正极集流体的两个表面上。
在一些实施例中，所述第一正极材料包括LiFePO 4、LiFe 0.5Mn 0.5PO 4、Li 0.9Fe 0.5Mn 0.45Ti 0.05PO 4、Li 0.9Fe 0.5Mn 0.45Ti 0.04Zr 0.01PO 4或Li 0.95FePO 3.95F 0.05中的至少一者。在一些实施例中，所述第二正极材料包括LiMnO 2、LiMn 0.9Ni 0.1O 2、LiMn 0.9Ni 0.05Cr 0.05O 2、Li 0.95MnO 1.95F 0.05或Li 0.95MnO 1.9S 0.05F 0.05中的至少一者。
在一些实施例中，1.5≤R×P/Q≤10。在一些实施例中，R×P/Q的值为0.5、1、1.5、2、2.5、3、3.5、4、5、6、7、8、9、10、11、12、13、14、15、16或这些数值中任意两者组成的范围。
在一些实施例中，R≤3.5Ω。在一些实施例中，R为0.2Ω、0.5Ω、1Ω、1.2Ω、1.5Ω、1.8Ω、2.0Ω、2.2Ω、2.5Ω、3.0Ω、3.2Ω、3.5Ω或这些数值中任意两者组成的范围。当R在上述范围时，有利于提升锂离子二次电池的循环性能和倍率性能。
在一些实施例中，1.6g/cm 3＜P＜2.6g/cm 3。在一些实施例中，P为1.6g/cm 3、1.8g/cm 3、2.0g/cm 3、2.2g/cm 3、2.4g/cm 3、2.6g/cm 3或这些数值中任意两者组成的范围。当P在上述范围时，有利于正极中电子和离子的迁移，从而提高锂离子二次电池的循环性能。
在一些实施例中，0.16g/1540.25mm 2＜Q＜0.45g/1540.25mm 2。在一些实施例中，Q为0.16g/1540.25mm 2、0.18g/1540.25mm 2、0.2g/1540.25mm 2、0.25g/1540.25mm 2、0.28g/1540.25mm 2、0.30g/1540.25mm 2、0.34g/1540.25mm 2、0.36g/1540.25mm 2、0.38g/1540.25mm 2、0.40g/1540.25mm 2、0.42g/1540.25mm 2、0.45g/1540.25mm 2或这些数值中任意两者组成的范围。当Q在上述范围时，能够在保证充放电容量的前提下，提高锂离子二次电池的循环性能和倍率性能。
在一些实施例中，所述第一正极材料和所述第二正极材料的质量比为5∶1至99∶1。在一些实施例中，所述第一正极材料和所述第二正极材料的质量比为5∶1、9∶1、10∶1、15∶1、20∶1、25∶1、30∶1、35∶1、40∶1、45∶1、50∶1、55∶1、60∶1、65∶1、70∶1、75∶1、80∶1、85∶1、90∶1、95∶1、99∶1或这些数值中任意两者组成的范围。当第一正极材料和第二正极材料的质量比在上述范围内时，正极中包括较高含量的第一正极材料，使得正极具有更高的结构稳定性，可减少正极材料结构破坏所造成的容量损失和阻抗增加，从而保持锂离子电池的循环稳定性和动力学性能。
在一些实施例中，基于所述正极材料层的总质量，所述第一正极材料的含量为80％至98％。在一些实施例中，基于所述正极材料层的总质量，所述第一正极材料的含量为80％、 82％、84％、85％、88％、90％、92％、94％、96％、98％或这些数值中任意两者组成的范围。
在一些实施例中，所述第二正极材料的X射线衍射谱在15°至16°范围内具有特征衍射峰A，和/或在18°至19°范围内具有特征衍射峰B，特征衍射峰A的强度I A和特征衍射峰B的强度I B的比值I A/I B满足式(3)：0＜I A/I B≤0.2    式(3)。
在一些实施例中，I A/I B的值为0.1、0.12、0.14、0.16、0.18、0.2或这些数值中任意两者组成的范围。
在一些实施例中，所述第二正极材料在首圈充电后的X射线衍射谱中，特征衍射峰A和特征衍射峰B均向低角度方向偏移，偏移幅度＜0.5°。在一些实施例中，偏移幅度为0.1°、0.2°、0.3°、0.4°、0.45°或这些数值中任意两者组成的范围。
在一些实施例中，所述正极材料层包括导电剂。在一些实施例中，所述导电剂包括石墨、超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯或碳纳米纤维中的至少一者。
在一些实施例中，基于所述正极材料层的总质量，所述导电剂的含量为0.5至20％。在一些实施例中，基于所述正极材料层的总质量，所述导电剂的含量为0.5％、1％、5％、8％、10％、12％、14％、16％、18％、20％或这些数值中任意两者组成的范围。
在一些实施例中，所述正极材料层包括粘结剂。在一些实施例中，所述粘结剂包括丁苯橡胶(SBR)、水性丙烯酸树脂、羧甲基纤维素(CMC)、聚偏二氟乙烯(PVDF)、聚四氟乙烯(PTFE)、聚乙烯醇缩丁醛(PVB)、乙烯-醋酸乙烯酯共聚物(EVA)或聚乙烯醇(PVA)中的至少一者。
在一些实施例中，基于所述正极材料层的总质量，所述粘结剂的含量为0.1至2.5％。在一些实施例中，基于所述正极材料层的总质量，所述粘结剂的含量为0.1％、0.2％、0.5％、0.8％、1％、1.2％、1.5％、1.8％、2％、2.5％或这些数值中任意两者组成的范围。
在一些实施例中，所述正极集流体包括金属箔材或多孔金属板。在一些实施例中，所述正极集流体包括铝、铜、镍、钛或银等金属或它们的合金的箔材或多孔板。在一些实施例中，所述正极集流体包括铜箔或铝箔中的至少一种。
在一些实施例中，所述正极集流体的厚度为5μm至20μm。在一些实施例中，所述正极集流体的厚度为5μm、8μm、10μm、12μm、15μm、18μm、20μm或这些数值中任意两者组成的范围。
在一些实施例中，所述正极可以通过如下方法获得：在溶剂中将正极活性材料、导电剂 和粘合剂混合，以制备活性材料组合物，并将该活性材料组合物涂覆在集流体上。在一些实施例中，所述溶剂可以包括N-甲基吡咯烷酮等，但不限于此。
本申请的正极能够充分发挥第一正极材料和第二正极材料之间的协同效应。一方面，首圈充电时，利用第二正极材料首次充电比容量高以及首效低的特点，有效弥补了生成SEI造成的活性锂损失，首次放电时有足够的锂离子回嵌至第一正极材料中，有效提升了电池的能量密度。另一方面，本申请所选用的第一正极材料的结构稳定，充放电过程体积变化小，循环稳定性较优。此外，通过对正极的膜片电阻、压实密度和面密度进行设计，能够进一步提升锂离子二次电池的能量密度、倍率性能和循环寿命。因此，采用本申请的正极，能够使锂离子二次电池获得高能量密度、良好的倍率性能和长循环寿命。
需要指出的是，正极的膜片电阻、压实密度和单面面密度是锂离子二次电池设计和制作中的关键参数。正极的膜片电阻过大，会恶化锂离子二次电池的循环性能和倍率性能。而压实密度过大或过小，都会使电池的循环性能和倍率性能变差。正极的单面面密度过大，电池的循环寿命降低，还会影响电解液的渗透，进而影响电池的倍率性能，特别是使得电池高倍率下的放电容量降低。而正极的单面面密度过小，意味着相同电池容量下集流体和隔膜的长度增加，增大了电池的欧姆内阻。
本申请在使正极同时包括第一正极材料和第二正极材料的情况下，通过对正极的膜片电阻、压实密度和单面面密度等参数进行综合设计，使锂离子二次电池的电化学性能达到预期的结果。
2、电解液
在一些实施例中，本申请电化学装置中使用的电解液包括电解质和溶解该电解质的溶剂。在一些实施例中，所述电解液包括添加剂，所述添加剂包括包含碳酸亚乙烯酯，其中基于所述电解液的总质量，所述碳酸亚乙烯酯的含量为0.05％至5％。
在一些实施例中，所述碳酸亚乙烯酯的含量为0.05％、1％、2％、3％、4％、5％或这些数值中任意两者组成的范围。
当电解液中添加剂含量在本申请的范围内时，可进一步提升锂离子二次电池的循环性能和能量密度。
在一些实施例中，所述电解液还可包括其它添加剂，其可以是任意可被用作锂离子二次电池的添加剂，本申请不做具体限制，可以根据实际需求进行选择。在一些实施例中，其它添加剂包括碳酸乙烯亚乙酯(VEC)、丁二腈(SN)、己二腈(AND)、1，3-丙烯磺酸内酯(PST)、 磺酸酯环状季铵盐、三(三甲基硅烷)磷酸酯(TMSP)或三(三甲基硅烷)硼酸酯(TMSB)中的至少一者。
在一些实施例中，所述电解液进一步包含任何可作为电解液的溶剂的非水溶剂。
在一些实施例中，所述非水溶剂包括，但不限于，以下中的一种或多种：环状碳酸酯、链状碳酸酯、环状羧酸酯、链状羧酸酯、环状醚、链状醚、含磷有机溶剂、含硫有机溶剂和芳香族含氟溶剂。
在一些实施例中，所述非水溶剂包括碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸丁烯酯(BC)、氟代碳酸乙烯酯(FEC)、甲酸甲酯(MF)、乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(PA)、丙酸甲酯(MP)、丙酸乙酯(EP)、丙酸丙酯(PP)、丁酸甲酯(MB)、丁酸乙酯(EB)、1，4-丁内酯(GBL)、环丁砜(SF)、二甲砜(MSM)、甲乙砜(EMS)或二乙砜(ESE)中的至少一者。
电解质没有特别限制。在一些实施例中，在锂二次电池的情况下，电解质包括锂盐。电解质的实例可包括，但不限于，六氟磷酸锂(LiPF 6)、四氟硼酸锂(LiBF 4)、高氯酸锂(LiClO 4)、六氟砷酸锂(LiAsF 6)、双氟磺酰亚胺锂(LiFSI)、双三氟甲磺酰亚胺锂(LiTFSI)、三氟甲磺酸锂(LiTFS)、二氟草酸硼酸锂(LiDFOB)、二草酸硼酸锂(LiBOB)、二氟磷酸锂(LiPO 2F 2)、二氟二草酸磷酸锂(LiDFOP)及四氟草酸磷酸锂(LiTFOP)。
电解质的含量没有特别限制，只要不损害本申请的效果即可。在一些实施例中，电解液中的锂的总摩尔浓度为大于0.3mol/L以上、大于0.4mol/L或大于0.5mol/L。在一些实施例中，电解液中的锂的总摩尔浓度为小于3mol/L、小于2.5mol/L或小于2.0mol/L以下。在一些实施例中，电解液中的锂的总摩尔浓度在上述任意两个数值所组成的范围内。当电解质浓度在上述范围内时，作为带电粒子的锂不会过少，并且可以使粘度处于适当的范围，因而容易确保良好的电导率。
3、负极
在一些实施例中，负极包括负极集流体和位于所述负极集流体的一个或两个表面上的负极活性物质层。所述负极活性物质层包含负极活性物质。负极活性物质层可以是一层或多层，多层负极活性物质中的每层可以包含相同或不同的负极活性物质。负极活性物质为任何 能够可逆地嵌入和脱嵌锂离子等金属离子的物质。在一些实施例中，负极活性物质的可充电容量大于负极活性物质的放电容量，以防止在充电期间锂金属无意地析出在负极上。
作为保持负极活性物质的集流体，负极集流体的实例包括，但不限于，铝、铜、镍、不锈钢、镀镍钢等金属材料。在一些实施例中，负极集流体为铜。
在负极集流体为金属材料的情况下，负极集流体形式可包括，但不限于，金属箔、金属圆柱、金属带卷、金属板、金属薄膜、金属板网、冲压金属、发泡金属等。在一些实施例中，负极集流体为金属薄膜。在一些实施例中，负极集流体为铜箔。在一些实施例中，负极集流体为基于压延法的压延铜箔或基于电解法的电解铜箔。
在一些实施例中，负极集流体的厚度为大于1μm或大于5μm。在一些实施例中，负极集流体的厚度为小于100μm或小于50μm。在一些实施例中，负极集流体的厚度在上述任意两个数值所组成的范围内。
负极活性物质没有特别限制，只要能够可逆地吸藏、放出锂离子即可。负极活性物质的实例可包括，但不限于，天然石墨、人造石墨等碳材料；硅(Si)、锡(Sn)等金属；或Si、Sn等金属元素的氧化物等。负极活性物质可以单独使用或组合使用。
在一些实施例中，负极活性物质层还可包括负极粘合剂。负极粘合剂可提高负极活性物质颗粒彼此间的结合和负极活性物质与集流体的结合。负极粘合剂的种类没有特别限制，只要是对于电解液或电极制造时使用的溶剂稳定的材料即可。在一些实施例中，负极粘合剂包括树脂粘合剂。树脂粘合剂的实例包括，但不限于，氟树脂、聚丙烯腈(PAN)、聚酰亚胺树脂、丙烯酸系树脂、聚烯烃树脂等。当使用水系溶剂制备负极合剂浆料时，负极粘合剂包括，但不限于，羧甲基纤维素(CMC)或其盐、苯乙烯-丁二烯橡胶(SBR)、聚丙烯酸(PAA)或其盐、聚乙烯醇等。
在一些实施例中，负极可以通过以下方法制备：在负极集流体上涂布包含负极活性物质、树脂粘合剂等的负极合剂浆料，干燥后，进行压延而在负极集流体的两面形成负极活性物质层，由此可以得到负极。
4、隔离膜
在一些实施例中，为了防止短路，在正极与负极之间通常设置有隔离膜。这种情况下，本申请的电解液通常渗入该隔离膜而使用。
对隔离膜的材料及形状没有特别限制，只要不显著损害本申请的效果即可。所述隔离膜 可为由对本申请的电解液稳定的材料所形成的树脂、玻璃纤维、无机物等。在一些实施例中，所述隔离膜包括保液性优异的多孔性片或无纺布状形态的物质等。树脂或玻璃纤维隔离膜的材料的实例可包括，但不限于，聚烯烃、芳香族聚酰胺、聚四氟乙烯、聚醚砜等。在一些实施例中，所述聚烯烃为聚乙烯或聚丙烯。在一些实施例中，所述聚烯烃为聚丙烯。上述隔离膜的材料可以单独使用或任意组合使用。
所述隔离膜还可为上述材料层积而成的材料，其实例包括，但不限于，按照聚丙烯、聚乙烯、聚丙烯的顺序层积而成的三层隔离膜等。
无机物的材料的实例可包括，但不限于，氧化铝、二氧化硅等氧化物、氮化铝、氮化硅等氮化物、硫酸盐(例如，硫酸钡、硫酸钙等)。无机物的形式可包括，但不限于，颗粒状或纤维状。
所述隔离膜的形态可为薄膜形态，其实例包括，但不限于，无纺布、织布、微多孔性膜等。在薄膜形态中，所述隔离膜的孔径为0.01μm至1μm，厚度为5μm至50μm。除了上述独立的薄膜状隔离膜以外，还可以使用下述隔离膜：通过使用树脂类的粘合剂在正极和/或负极的表面形成含有上述无机物颗粒的复合多孔层而形成的隔离膜，例如，将氟树脂作为粘合剂使90％粒径小于1μm的氧化铝颗粒在正极的两面形成多孔层而形成的隔离膜。
所述隔离膜的厚度是任意的。在一些实施例中，所述隔离膜的厚度为大于1μm、大于5μm或大于8μm。在一些实施例中，所述隔离膜的厚度为小于50μm、小于40μm或小于30μm。在一些实施例中，所述隔离膜的厚度在上述任意两个数值所组成的范围内。当所述隔离膜的厚度在上述范围内时，则可以确保绝缘性和机械强度，并可以确保电化学装置的倍率特性和能量密度。
在使用多孔性片或无纺布等多孔质材料作为隔离膜时，隔离膜的孔隙率是任意的。在一些实施例中，所述隔离膜的孔隙率为大于10％、大于15％或大于20％。在一些实施例中，所述隔离膜的孔隙率为小于60％、小于50％或小于45％。在一些实施例中，所述隔离膜的孔隙率在上述任意两个数值所组成的范围内。当所述隔离膜的孔隙率在上述范围内时，可以确保绝缘性和机械强度，并可以抑制膜电阻，使电化学装置具有良好的安全特性。
所述隔离膜的平均孔径也是任意的。在一些实施例中，所述隔离膜的平均孔径为小于0.5μm或小于0.2μm。在一些实施例中，所述隔离膜的平均孔径为大于0.05μm。在一些实施例中，所述隔离膜的平均孔径在上述任意两个数值所组成的范围内。若所述隔离膜的平均孔径超过上述范围，则容易发生短路。当隔离膜的平均孔径在上述范围内时，使电化学装置具有 良好的安全特性。
5、电化学装置
本申请的电化学装置包括发生电化学反应的任何装置，它的具体实例包括所有种类的一次电池、二次电池、燃料电池、太阳能电池或电容器。特别地，该电化学装置是锂二次电池，包括锂金属二次电池或锂离子二次电池。
本申请另提供了一种电子装置，其包括根据本申请所述的电化学装置。
本申请的电化学装置的用途没有特别限定，其可用于现有技术中已知的任何电子装置。在一些实施例中，本申请的电化学装置可用于，但不限于，笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
下面以锂离子电池为例并且结合具体的实施例说明锂离子电池的制备，本领域的技术人员将理解，本申请中描述的制备方法仅是实例，其他任何合适的制备方法均在本申请的范围内。
实施例
以下说明根据本申请的锂离子电池的实施例和对比例进行性能评估。
一、锂离子电池的制备
实施例1
1、负极的制备
将负极活性材料人造石墨、增稠剂羧甲基纤维素钠(CMC)、粘结剂(SBR)及导电炭黑按照质量比95.7∶1.0∶1.8∶1.5进行混合，加入溶剂去离子水，在真空搅拌机作用下获得负极浆料；将负极浆料均匀涂覆在负极集流体铜箔上。之后转移至烘箱干燥，干燥温度为120℃，再经过冷压、分切、焊接极耳，得到负极。
2、正极的制备
将第一正极材料LiFePO 4、第二正极材料LiMnO 2、粘结剂PVDF及导电炭黑进行混合，其中LiFePO 4、LiMnO 2、PVDF及导电炭黑的质量比为90.4∶6.0∶2.1∶1.5，加入溶剂N-甲基吡咯烷酮(NMP)，在真空搅拌作用下搅拌至均一透明状体系，获得正极浆料。将正极浆料均匀涂覆在正极集流体铝箔上，之后转移至烘箱干燥，烘干温度为120℃。再经过冷压、分切、焊接极耳，得到正极。其中基于所述正极材料层的总质量，第一正极材料LiFePO 4的含量为90.4％，第二正极材料LiMnO 2的含量为6.0％。
3、电解液的制备
将碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)及碳酸二乙酯(DEC)按照体积比为1∶1∶1混合均匀，得到有机溶剂。将LiPF 6溶解于上述有机溶剂中得到基础电解液，其中基础电解液中LiPF 6的浓度为1mol/L。在该基础电解液中加入碳酸亚乙烯酯，混合均匀，得到电解液，基于该电解液的总质量，碳酸亚乙烯酯的含量为3％。
4、隔离膜的制备
以具有氧化铝涂层的聚乙烯多孔膜作为隔离膜，厚度9μm。
5、锂离子电池的制备
将得到的正极、隔离膜和负极按次序卷绕，置于外包装箔中，留下注液口。从注液口灌注电解液，封装，再经过化成、容量等工序制得锂离子电池。
实施例2至16：
实施例2至16与实施例1的区别在于正极材料的种类和相关性能参数以及电解液中添加剂的含量不同，详见表1。
对比例1：
对比例1与实施例1的区别在于对比例1中的正极材料中仅含有LiFePO 4。
对比例2：
对比例2与实施例1的区别在于对比例2中的正极材料中仅含有LiMnO 2。
对比例3至4：
对比例3至4与实施例1的区别在于正极中第一正极材料和第二正极材料的质量比不同，详见表1。
对比例5至6：
对比例5至6与实施例1的区别在于正极的膜片电阻、压实密度和单面面密度不同，详见表1。
对比例7至8：
对比例7至8与实施例1的区别在于电解液中的碳酸亚乙烯酯的质量百分含量不同，详见表1。
二、测试方法
1、正极的膜片电阻的测试方法
采用日置BT3562型电阻测试仪测试正极的膜片电阻，测试方法包括：将正极夹持于内阻测试仪的两个导电端子之间，并施加压力固定，测试正极的电阻R，其中导电端子的直径为14mm，施加压力为15MPa至27MPa，采点时间的范围为5s-17s。
2、锂离子二次电池的高温循环性能的测试方法
在60℃下，将锂离子二次电池以1C倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，再以1C倍率恒流放电至2.5V，此为一个充放电循环，记录锂离子二次电池第一次循环的放电容量。将锂离子二次电池按照上述方法进行充放电循环，记录每一次循环的放电容量，直至锂离子二次电池的放电容量衰减至第一次循环的放电容量的80％，记录此时的充放电循环次数。
3、锂离子二次电池的倍率性能的测试方法
在25℃下，将锂离子二次电池以0.5C倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，再以0.5C倍率恒流放电至2.5V，记录0.5C倍率的放电容量。
在25℃下，将锂离子二次电池以0.5C倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，再以2C倍率恒流放电至2.5V，记录2C倍率的放电容量。
锂离子二次电池2C倍率放电容量保持率(％)＝2C倍率放电容量/0.5C倍率放电容量×100％。
4、锂离子二次电池的能量密度的测试方法
在25℃下，将锂离子二次电池以0.2C倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，之后静置30分钟，再以0.2C倍率恒流放电至2.5V，记录锂离子二次电池0.2C倍率的放电容量D 0(Ah)和放电平台V 0(V)。称量锂离子电池的重量，记为m 0(kg)。
按如下公式计算锂离子二次电池的能量密度：
能量密度＝D 0*V 0/m 0。
三、测试结果
表1示出了对比例1至8与实施例1至16中正极的组成和相关性能参数以及电解液中添加剂的种类和含量。其中第一和第二正极材料的含量为基于正极材料层的总质量计算得到，且电解液中碳酸亚乙烯酯的含量为基于电解液的总质量计算得到。
表1
Figure PCTCN2022075970-appb-000001
Figure PCTCN2022075970-appb-000002
其中“/”表示不存在该物质。
表2示出了对比例1至8与实施例1至16中锂离子二次电池的高温循环性能、倍率性能和能量密度。
表2
序号 R·P/Q 高温循环次数 倍率性能(％) 能量密度(Wh/Kg)
对比例1 4.71 1450 98.4 162
对比例2 7.29 1 81.2 151
对比例3 4.71 1487 98.3 163
对比例4 4.71 2212 86.3 159
对比例5 56.9 1642 93.2 113
对比例6 0.36 1792 94.4 170
对比例7 4.71 1128 98.3 171
对比例8 4.71 2131 96.9 171
实施例1 4.71 2398 97.5 172
实施例2 4.71 2417 97.4 190
实施例3 4.71 2432 97.6 190
实施例4 4.71 2459 97.9 191
实施例5 4.71 2325 97.4 172
实施例6 4.71 2392 97.1 173
实施例7 4.71 2298 97.4 171
实施例8 4.71 2312 97.1 170
实施例9 4.71 2348 97.0 172
实施例10 4.71 2036 98.0 168
实施例11 4.71 2728 96.5 175
实施例12 0.67 2322 97.6 181
实施例13 8.80 2286 97.5 163
实施例14 15.2 2285 97.7 161
实施例15 4.71 2201 97.8 172
实施例16 4.71 2425 97.4 171
通过比较上述实施例和对比可知，与正极仅包含第一正极材料或第二正极材料的锂离子电池相比，正极同时包含第一正极材料和第二正极材料的锂离子电池具有显著提高的高温循环性能和能量密度，而倍率性能没有明显的变化。由此可见，共同使用第一正极材料和第二正极材料会产生协同效应。不受理论约束，上述协同效应的产生可能有以下几方面原因：第一方面，本申请采用的第二正极材料的表面游离锂含量极少，将其加入正极，所得浆料稳定 性好，加工性能优良；第二方面，本申请所用第二正极材料首次充电比容量高、首效低，可更好的弥补因生成SEI造成的活性锂损失，放电时有更多的锂离子回嵌至第一正极材料晶格中，有效提升了锂离子二次电池的能量密度；以及第三方面，第一正极材料的结构稳定、循环性能好，通过控制正极的膜片电阻R，压实密度P和单面面密度Q在本申请范围内，能够使锂离子二次电池具有良好的循环性能和倍率性能。
此外，由对比例7和实施例1的比较结果可以看出，电解液中添加的碳酸亚乙烯酯能够和同时包含第一正极材料和第二正极材料的正极发挥协同作用，这可能是由于在首次充电时，由于第二正极材料脱出的大量活性锂嵌入负极，导致负极的真实电位进一步降低，造成电解液中溶剂的持续还原，影响循环性能，使用碳酸亚乙烯酯添加剂，可以诱导生成更加致密和轻薄的SEI层，阻止了电解液的持续消耗。
整个说明书中对“一些实施例”、“部分实施例”、“一个实施例”、“另一举例”、“举例”、“具体举例”或“部分举例”的引用，其所代表的意思是在本申请中的至少一个实施例或举例包含了该实施例或举例中所描述的特定特征、结构、材料或特性。因此，在整个说明书中的各处所出现的描述，例如：“在一些实施例中”、“在实施例中”、“在一个实施例中”、“在另一个举例中”，“在一个举例中”、“在特定举例中”或“举例“，其不必然是引用本申请中的相同的实施例或示例。此外，本文中的特定特征、结构、材料或特性可以以任何合适的方式在一个或多个实施例或举例中结合。
尽管已经演示和描述了说明性实施例，本领域技术人员应该理解上述实施例不能被解释为对本申请的限制，并且可以在不脱离本申请的精神、原理及范围的情况下对实施例进行改变，替代和修改。

Claims (12)

  1. 一种电化学装置，其包括正极、负极和电解液，
    其中所述正极包含正极集流体和位于所述正极集流体的至少一个表面上的正极材料层，所述正极材料层包括式(I)所示的第一正极材料：
    Li 1+xFe yMn zM 1-y-zPO 4-tA t     式(I)，
    其中，-0.1＜x＜0.1，0＜y≤1，0≤z≤1，0＜y+z≤1，0≤t＜0.2，M包括Ti、Zr、V或Cr中的至少一种，且A包括S，N，F，Cl或Br中的至少一种；和
    式(II)所示的第二正极材料：
    Li 1+rMn 1-pX pO 2-sT s     式(II)，
    其中，-0.1＜r＜0.2，0≤p＜0.2，0≤s＜0.2，X包括Fe、Co、Ni、Ti、Zn、Mg、Al、V、Cr或Zr中的至少一种，且T包括S、N、F、Cl或Br中的至少一种；并且
    所述正极满足式(1)：
    0.5≤R×P/Q≤16     式(1)，
    其中，R是所述正极的电阻，单位是Ω；P是所述正极的压实密度，单位为g/cm 3；且Q是所述正极的单面面密度，单位为g/1540.25mm 2。
  2. 根据权利要求1所述的电化学装置，其中所述正极满足式(2)：
    1.5≤R×P/Q≤10     式(2)。
  3. 根据权利要求1所述的电化学装置，其中R≤3.5Ω。
  4. 根据权利要求1所述的电化学装置，其中1.6g/cm 3＜P＜2.6g/cm 3。
  5. 根据权利要求1所述的电化学装置，其中0.16g/1540.25mm 2＜Q＜0.45g/1540.25mm 2。
  6. 根据权利要求1所述的电化学装置，其中所述第一正极材料和所述第二正极材料的质量比为5∶1至99∶1。
  7. 根据权利要求1所述的电化学装置，其中基于所述正极材料层的总质量，所述 第一正极材料的含量为80％至98％。
  8. 根据权利要求1所述的电化学装置，其中所述第二正极材料的X射线衍射谱在15°至16°范围内具有特征衍射峰A，和/或在18°至19°范围内具有特征衍射峰B，特征衍射峰A的强度I A和特征衍射峰B的强度I B的比值I A/I B满足式(3)：
    0＜I A/I B≤0.2   式(3)。
  9. 根据权利要求8所述的电化学装置，其中所述第二正极材料在首圈充电后的X射线衍射谱中，特征衍射峰A和特征衍射峰B均向低角度方向偏移，偏移幅度＜0.5°。
  10. 根据权利要求1所述的电化学装置，其中所述第一正极材料包括LiFePO 4、LiFe 0.5Mn 0.5PO 4、Li 0.9Fe 0.5Mn 0.45Ti 0.05PO 4、Li 0.9Fe 0.5Mn 0.45Ti 0.04Zr 0.01PO 4或Li 0.95FePO 3.95F 0.05中的至少一者；和/或所述第二正极材料包括LiMnO 2、LiMn 0.9Ni 0.1O 2、LiMn 0.9Ni 0.05Cr 0.05O 2、Li 0.95MnO 1.95F 0.05或Li 0.95MnO 1.9S 0.05F 0.05中的至少一者。
  11. 根据权利要求1所述的电化学装置，其中所述电解液包含碳酸亚乙烯酯，其中基于所述电解液的总质量，所述碳酸亚乙烯酯的含量为0.05％至5％。
  12. 一种电子装置，其包括根据权利要求1-11中任一项所述的电化学装置。
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Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114784366A (zh) * 2022-04-26 2022-07-22 惠州市豪鹏科技有限公司 一种锂离子电池
CN114725392A (zh) * 2022-04-26 2022-07-08 惠州市豪鹏科技有限公司 一种锂离子电池
CN118367149B (zh) * 2024-06-17 2025-11-18 深圳市德方创域新能源科技有限公司 补锂材料及其制备方法、正极材料和二次电池

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1771618A (zh) * 2003-04-09 2006-05-10 株式会社Lg化学 含有改善过放电性能用添加剂的阴极活性物质和使用它的锂二次电池
US20140322605A1 (en) * 2012-08-02 2014-10-30 Lg Chem, Ltd. Mixed cathode active material having improved power characteristics and lithium secondary battery including the same
CN106299502A (zh) * 2016-08-31 2017-01-04 桐乡市众胜能源科技有限公司 提高锂离子电池能量密度和循环寿命的方法
CN110265627A (zh) * 2018-09-28 2019-09-20 宁德时代新能源科技股份有限公司 正极极片及锂离子二次电池

Family Cites Families (36)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9807774D0 (en) * 1998-04-09 1998-06-10 Danionics As Electrochemical cell
JP4608735B2 (ja) * 2000-05-16 2011-01-12 ソニー株式会社 非水電解質二次電池の充電方法
DK200200615A (da) 2001-12-19 2003-06-20 Fmc Corp Lithiummetaldispersion i sekundære batterianoder
JP2005521220A (ja) * 2002-03-22 2005-07-14 エルジー ケミカル エルティーディー． 過放電防止剤を含むリチウム二次電池
KR100437340B1 (ko) * 2002-05-13 2004-06-25 삼성에스디아이 주식회사 리튬 이차 전지용 양극 활물질의 제조 방법
KR20060111393A (ko) * 2005-04-22 2006-10-27 주식회사 엘지화학 대용량 비가역 물질을 포함하는 새로운 시스템의 리튬 이온전지
CN101232096B (zh) * 2008-02-03 2012-10-17 深圳市比克电池有限公司 一种锂离子电池电芯体系
KR101093705B1 (ko) 2009-04-29 2011-12-19 삼성에스디아이 주식회사 리튬 이차 전지
JP5341837B2 (ja) * 2009-08-25 2013-11-13 株式会社東芝 正極、非水電解質電池及び電池パック
KR101754800B1 (ko) * 2010-08-19 2017-07-06 삼성전자주식회사 양극, 그 제조방법 및 이를 채용한 리튬전지
KR101423812B1 (ko) * 2011-08-31 2014-07-25 주식회사 엘지화학 산소 제거제를 포함하는 리튬 이차전지
KR20120083251A (ko) * 2012-06-08 2012-07-25 주식회사 엘지화학 리튬 이차 전지 및 그 제조방법
CN102856552B (zh) * 2012-10-10 2015-11-25 中国科学院宁波材料技术与工程研究所 一种锂离子电池正极材料、其制备方法和锂离子电池
CN109659496A (zh) 2013-03-05 2019-04-19 中国科学院宁波材料技术与工程研究所 一种锂离子电池正极膜及其制备和应用
EP3157089A4 (en) * 2014-06-10 2017-10-25 Hitachi Chemical Co., Ltd. Lithium ion secondary cell
KR102172153B1 (ko) * 2016-06-16 2020-10-30 주식회사 엘지화학 용량 및 안전성이 개선된 리튬 이차전지용 양극 및 이를 포함하는 리튬 이차전지
CN106531984B (zh) * 2016-09-30 2019-04-02 罗仕雄 一种低温锂离子电池
CN107706351A (zh) * 2017-09-30 2018-02-16 深圳市贝特瑞纳米科技有限公司 一种正极片、制备方法及包含其的锂离子电池
KR102646712B1 (ko) * 2017-11-22 2024-03-12 주식회사 엘지에너지솔루션 리튬 이차전지용 양극 첨가제의 제조방법
WO2019151724A1 (ko) * 2018-01-30 2019-08-08 주식회사 엘지화학 고온 저장 특성이 향상된 리튬 이차전지
CN108321381A (zh) * 2018-03-21 2018-07-24 苏州林奈新能源有限公司 一种Ti掺杂的镍钴铝三元锂离子电池正极材料、制备方法及用途
CN110459736B (zh) * 2018-05-07 2021-01-12 宁德新能源科技有限公司 正极材料及含有该正极材料的正极极片和锂离子电池
US20190372155A1 (en) * 2018-05-30 2019-12-05 GM Global Technology Operations LLC Methods of manufacturing high-active-material-loading composite electrodes and all-solid-state batteries including composite electrodes
CN110265622B (zh) * 2018-06-28 2020-12-08 宁德时代新能源科技股份有限公司 正极极片及锂离子二次电池
CN110660959B (zh) * 2018-06-29 2021-11-09 宁德时代新能源科技股份有限公司 正极极片及钠离子电池
CN112909319B (zh) * 2018-09-19 2022-04-22 宁德时代新能源科技股份有限公司 锂离子二次电池与包含其的电子产品、电动交通工具及机械设备
CN110265625B (zh) * 2018-11-12 2020-12-04 宁德时代新能源科技股份有限公司 负极极片及锂离子二次电池
US20200313157A1 (en) * 2019-03-28 2020-10-01 Uchicago Argonne, Llc Over-lithiated cathodes for lithium ion batteries and processes of manufacture
CN109860584B (zh) * 2019-04-01 2021-11-30 安普瑞斯（无锡）有限公司 一种高能量密度锂离子二次电池
WO2021189477A1 (zh) * 2020-03-27 2021-09-30 宁德新能源科技有限公司 电化学装置及包含其的电子装置
CN111430795B (zh) * 2020-03-31 2021-06-04 宁德新能源科技有限公司 一种电化学装置及包括其的电子装置
CN111653770A (zh) * 2020-06-10 2020-09-11 广东邦普循环科技有限公司 一种正极添加剂及其制备方法和应用
CN112382749B (zh) * 2020-07-03 2024-04-12 华中科技大学 一种锂离子电池正极材料及其制备方法
CN113036082B (zh) * 2021-03-05 2022-06-03 江苏正力新能电池技术有限公司 一种正极极片、正极极片的制备方法和锂离子二次电池
CN113140722B (zh) * 2021-04-22 2022-04-15 远景动力技术(江苏)有限公司 一种正极补锂材料及其制备方法和应用
CN118352602A (zh) * 2021-06-30 2024-07-16 宁德新能源科技有限公司 一种电化学装置及电子装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1771618A (zh) * 2003-04-09 2006-05-10 株式会社Lg化学 含有改善过放电性能用添加剂的阴极活性物质和使用它的锂二次电池
US20140322605A1 (en) * 2012-08-02 2014-10-30 Lg Chem, Ltd. Mixed cathode active material having improved power characteristics and lithium secondary battery including the same
CN106299502A (zh) * 2016-08-31 2017-01-04 桐乡市众胜能源科技有限公司 提高锂离子电池能量密度和循环寿命的方法
CN110265627A (zh) * 2018-09-28 2019-09-20 宁德时代新能源科技股份有限公司 正极极片及锂离子二次电池

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