WO2024011355A1 - 钠离子电池电解液、包含其的钠离子电池及用电装置 - Google Patents

钠离子电池电解液、包含其的钠离子电池及用电装置 Download PDF

Info

Publication number
WO2024011355A1
WO2024011355A1 PCT/CN2022/104914 CN2022104914W WO2024011355A1 WO 2024011355 A1 WO2024011355 A1 WO 2024011355A1 CN 2022104914 W CN2022104914 W CN 2022104914W WO 2024011355 A1 WO2024011355 A1 WO 2024011355A1
Authority
WO
WIPO (PCT)
Prior art keywords
sodium
borate
group
optionally
ion battery
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2022/104914
Other languages
English (en)
French (fr)
Inventor
秦猛
官英杰
马晴岩
赵玉珍
温严
黄起森
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Contemporary Amperex Technology Co Ltd
Original Assignee
Contemporary Amperex Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Contemporary Amperex Technology Co Ltd filed Critical Contemporary Amperex Technology Co Ltd
Priority to CN202280090970.8A priority Critical patent/CN118648152A/zh
Priority to JP2024566429A priority patent/JP2025517831A/ja
Priority to PCT/CN2022/104914 priority patent/WO2024011355A1/zh
Priority to EP22950486.5A priority patent/EP4517902A4/en
Priority to KR1020247038128A priority patent/KR20250004289A/ko
Publication of WO2024011355A1 publication Critical patent/WO2024011355A1/zh
Priority to US18/953,118 priority patent/US20250079521A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • 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
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • 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
    • H01M10/0568—Liquid materials characterised by the solutes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • 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
    • H01M10/0569—Liquid materials characterised by the solvents
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0037—Mixture of solvents
    • 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 technical field of secondary batteries, and in particular to an electrolyte for a sodium-ion battery and a sodium-ion battery containing the same, as well as battery modules, battery packs and electrical devices containing the sodium-ion battery.
  • lithium-ion batteries In recent years, the demand for lithium-ion batteries has been increasing, but limited lithium resources have restricted the sustainable development of lithium-ion batteries. As an important supplement to lithium-ion batteries, sodium-ion batteries have received more and more attention.
  • This application was made in view of the above-mentioned problems, and its purpose is to reduce the volume expansion of a sodium-ion battery after cycling and to suppress the formation of sodium dendrites on the electrode.
  • the first aspect of the present application provides a sodium ion battery electrolyte, wherein the electrolyte contains an ether compound as a solvent, a sodium borate compound as a sodium salt, and a borate ester as an additive.
  • the electrolyte contains an ether compound as a solvent, a sodium borate compound as a sodium salt, and a borate ester as an additive.
  • Compound, the proportion of the ether compound in all solvents of the electrolyte solution is more than 50% by weight.
  • this application can suppress the volume expansion and sodium dendrite growth of sodium-ion batteries after cycling through a specific combination in the electrolyte. Therefore, the sodium-ion battery containing the electrolyte has better Coulombic efficiency and cycle performance.
  • the boronic acid ester compound has the structure of the following formula (I):
  • R 1 , R 2 and R 3 are the same or different and are selected from alkyl, aryl, alkylsilyl, alkenyl, alkynyl, cyanoalkyl, the above groups are optionally substituted by halogen, optionally Land, the halogen is fluorine; optionally, R 1 , R 2 , R 3 are the same or different and are selected from C1-C6 alkyl, C1-C6 haloalkyl, C6-C12 aryl, C6-C12 haloaryl group, C1-C6 alkylsilyl group, C2-C6 alkenyl group, C2-C6 alkynyl group, cyano-C1-C6 alkyl group; optionally, at least one of R 1 , R 2 and R 3 represents C1-C6 fluoroalkyl or C6-C12 fluoroaryl;
  • the borate ester compound is selected from the group consisting of trimethyl borate, triethyl borate, tripropyl borate, tributyl borate, tris(2,2,2-trifluoroethyl) borate, tris (Hexafluoroisopropyl) borate, triphenyl borate, tris (trimethylsilyl) borate, tris (triethylsilyl) borate, tris (pentafluorophenyl) borate One or more of acid ester, (di-n-butyl) (vinyl) borate, (di-n-butyl) (propargyl) borate, tris (2-cyanoethyl) borate ; Further optionally, the borate ester compound is one or more selected from the group consisting of trimethyl borate, triethyl borate, tripropyl borate, and tributyl borate. In particular, boronic acid ester compounds with smaller molecules are advantageous.
  • borate ester compounds By further selecting borate ester compounds, the volume expansion of the battery can be further reduced and the cycle performance and Coulombic efficiency of the battery can be improved.
  • the content of the borate ester compound is 0.5% to 10% by weight, optionally 1% to 5% by weight, such as 2% by weight, based on the total weight of the electrolyte.
  • the volume expansion of the battery can be further reduced and the cycle performance and Coulombic efficiency of the battery can be improved.
  • the sodium borate compound is one or more selected from sodium difluoroborate and compounds having the following formula (II) structure
  • R 4 , R 5 , R 6 , and R 7 are each independently selected from halogen atoms, alkyl groups, cyano groups, alkoxy groups, and aryl groups, wherein the alkyl groups, alkoxy groups, and aryl groups are optionally replaced by halogen atoms. Substituted, optionally, the halogen is fluorine; or R 4 and R 5 together and/or R 6 and R 7 together form the structure of formula (a)
  • R 4 , R 5 , R 6 , and R 7 are each independently selected from a halogen atom, C1-C6 alkyl group, C1-C6 haloalkyl group, cyano group, C1-C6 alkoxy group, phenyl group, or R 4 and R 5 together and/or R 6 and R 7 together form the structure of formula (a); optionally, at least one of R 4 , R 5 , R 6 , and R 7 represents a C1-C6 fluoroalkyl group ;
  • the sodium borate compound is selected from the group consisting of sodium difluoroborate, sodium tetrafluoroborate, sodium dioxaloborate, sodium difluoroxaloborate, sodium tetraphenylborate, sodium tetracyanoborate, tetrakis(trifluoromethyl) )Sodium borate, sodium bis(trifluoromethyl)difluoroborate, sodium pentafluoroethyltrifluoroborate, sodium dicyanooxaloborate, sodium methoxytricyanoborate, sodium ethoxytricyanoborate, One or more of sodium tetramethoxyborate, sodium tetraethoxyborate, and sodium cyanotris(2,2,2 trifluoroethyl)borate.
  • the volume expansion of the battery can be further reduced and the cycle performance and Coulombic efficiency of the battery can be improved.
  • the concentration of the sodium borate compound is 0.5M-8M, optionally 1M-4M, based on the total volume of the electrolyte.
  • the volume expansion of the battery can be further reduced and the cycle performance and Coulombic efficiency of the battery can be improved.
  • the ether compound is selected from the group consisting of aliphatic ethers with 4-20 carbon atoms, alicyclic ethers with 3-8 carbon atoms, and aromatic ethers with 7-20 carbon atoms. , one or more crown ethers; optionally, the ether compound is selected from the group consisting of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether.
  • ether One or more of ether, tetraglyme, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether; further optionally, the ether compound is One or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and diglyme.
  • the proportion of the ether compound in all solvents of the electrolyte is more than 60% by weight, optionally more than 80% by weight, and further optionally, the solvent is composed of ethers.
  • Compound composition is more than 60% by weight, optionally more than 80% by weight, and further optionally, the solvent is composed of ethers.
  • a second aspect of the application also provides a sodium ion battery, which includes the electrolyte of the first aspect of the application.
  • a third aspect of the present application provides a battery module, including the sodium ion battery of the second aspect of the present application.
  • a fourth aspect of the application provides a battery pack, including the battery module of the third aspect of the application.
  • a fifth aspect of the present application provides an electrical device, including at least one selected from the sodium ion battery of the second aspect of the present application, the battery module of the third aspect of the present application, or the battery pack of the fourth aspect of the present application. kind.
  • Figure 1 is a schematic diagram of a sodium ion battery according to an embodiment of the present application.
  • FIG. 2 is an exploded view of the sodium ion battery according to one 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 an electrical device using a sodium-ion 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).
  • the volume of the battery may expand, and sodium dendrites may grow on the electrode.
  • the volume expansion of the battery and the growth of sodium dendrites will lead to a reduction in the Coulombic efficiency of the battery, a short cycle life, and even affect the safety performance of the battery. Therefore, for sodium-ion batteries, there is a need to reduce the volume expansion after cycling and suppress the formation of sodium dendrites.
  • the present application provides a sodium ion battery electrolyte, wherein the electrolyte contains an ether compound as a solvent, a sodium borate compound as a sodium salt, and a borate ester as an additive. compounds, and the proportion of the ether compounds in all solvents of the electrolyte solution is more than 50% by weight.
  • the boronic acid ester compound has the structure of the following formula (I):
  • R 1 , R 2 and R 3 are the same or different and are selected from alkyl, aryl, alkylsilyl, alkenyl, alkynyl, cyanoalkyl, the above groups are optionally substituted by halogen, optionally Land, the halogen is fluorine; optionally, R 1 , R 2 , R 3 are the same or different and are selected from C1-C6 alkyl, C1-C6 haloalkyl, C6-C12 aryl, C6-C12 haloaryl group, C1-C6 alkylsilyl group, C2-C6 alkenyl group, C2-C6 alkynyl group, cyano-C1-C6 alkyl group; optionally, at least one of R 1 , R 2 and R 3 represents C1-C6 fluoroalkyl or C6-C12 fluoroaryl;
  • the borate ester compound is selected from the group consisting of trimethyl borate, triethyl borate, tripropyl borate, tributyl borate, tris(2,2,2-trifluoroethyl) borate, tris (Hexafluoroisopropyl) borate, triphenyl borate, tris (trimethylsilyl) borate, tris (triethylsilyl) borate, tris (pentafluorophenyl) borate One or more of acid ester, (di-n-butyl) (vinyl) borate, (di-n-butyl) (propargyl) borate, tris (2-cyanoethyl) borate ; Further optionally, the borate ester compound is one or more selected from the group consisting of trimethyl borate, triethyl borate, tripropyl borate, and tributyl borate. In particular, boronic acid ester compounds with smaller molecules are advantageous.
  • the volume expansion of the battery can be further reduced and the cycle performance and Coulombic efficiency of the battery can be improved.
  • the borate compound contains fluorine
  • the NaF in the SEI layer can further provide protection for the negative electrode.
  • the content of the borate ester compound is 0.5% to 10% by weight, optionally 1% to 5% by weight, such as 2% to 3% by weight, based on the electrolyte solution. Total weight.
  • the volume expansion of the battery can be further reduced and the cycle performance and Coulombic efficiency of the battery can be improved.
  • the sodium borate compound is one or more selected from sodium difluoroborate and compounds having the following formula (II) structure
  • R 4 , R 5 , R 6 , and R 7 are each independently selected from halogen atoms, alkyl groups, cyano groups, alkoxy groups, and aryl groups, wherein the alkyl groups, alkoxy groups, and aryl groups are optionally replaced by halogen atoms. Substituted, optionally, the halogen is fluorine; or R 4 and R 5 together and/or R 6 and R 7 together form the structure of formula (a)
  • R 4 , R 5 , R 6 , and R 7 are each independently selected from a halogen atom, C1-C6 alkyl group, C1-C6 haloalkyl group, cyano group, C1-C6 alkoxy group, phenyl group, or R 4 and R 5 together and/or R 6 and R 7 together form the structure of formula (a); optionally, at least one of R 4 , R 5 , R 6 , and R 7 represents a C1-C6 fluoroalkyl group ;
  • the sodium borate compound is selected from the group consisting of sodium difluoroborate, sodium tetrafluoroborate, sodium dioxaloborate, sodium difluoroxaloborate, sodium tetraphenylborate, sodium tetracyanoborate, tetrakis(trifluoromethyl) )Sodium borate, sodium bis(trifluoromethyl)difluoroborate, sodium pentafluoroethyltrifluoroborate, sodium dicyanooxaloborate, sodium methoxytricyanoborate, sodium ethoxytricyanoborate, One or more of sodium tetramethoxyborate, sodium tetraethoxyborate, and sodium cyanotris(2,2,2 trifluoroethyl)borate.
  • sodium borate compounds By further selecting sodium borate compounds, the volume expansion of the battery can be further reduced and the cycle performance and Coulombic efficiency of the battery can be improved. Especially when sodium borate compounds contain fluorine, the NaF in the SEI layer can further protect the negative electrode.
  • the concentration of the sodium borate compound is 0.5M-8M, optionally 1M-4M, such as 1M-2M, such as 1.5M, based on the total volume of the electrolyte.
  • the volume expansion of the battery can be further reduced and the cycle performance and Coulombic efficiency of the battery can be improved.
  • the ether compound is selected from the group consisting of aliphatic ethers with 4-20 carbon atoms, alicyclic ethers with 3-8 carbon atoms, and aromatic ethers with 7-20 carbon atoms. , one or more crown ethers; optionally, the ether compound is selected from the group consisting of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether.
  • ether One or more of ether, tetraglyme, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether; further optionally, the ether compound is One or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and diglyme.
  • a stable electrode/electrolyte interface can be constructed on the surface of sodium metal anodes, carbon material anodes and other non-carbon material anodes, forming a stable solid electrolyte interface (SEI), reducing electrochemical polarization, thereby It is beneficial to inhibit the growth of sodium dendrites and battery volume expansion.
  • SEI solid electrolyte interface
  • the proportion of the ether compound in all solvents of the electrolyte is more than 60% by weight, or more than 70% by weight, optionally more than 80% by weight, such as 85% by weight. More than 90% by weight, more than 95% by weight, or more than 98% by weight. Further optionally, the solvent consists of ether compounds.
  • a stable electrode/electrolyte interface can be constructed on the surface of the negative electrode, forming a stable solid electrolyte interface, which is beneficial to inhibiting the growth of sodium dendrites and battery volume expansion, and The cycle performance and Coulombic efficiency of the battery can be further improved.
  • the electrolyte plays a role in conducting ions between the positive electrode piece and the negative electrode piece.
  • the electrolyte includes electrolyte salts and solvents.
  • the electrolyte salt is sodium salt.
  • the sodium borate compound itself can serve as an electrolyte salt.
  • the electrolyte salt may further include NaClO 4 , NaPF 6 , NaBF 4 , NaTFSI (sodium bistrifluoromethanesulfonyl imide), NaFSI (bisfluorosulfonyl sodium One or more substances in sodium imide).
  • the total molar concentration of the electrolyte salts is 0.5M to 8M, optionally 1M to 4M, based on the total volume of electrolyte
  • the solvent of the electrolyte also contains a solvent selected from the group consisting of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, and dipropyl carbonate.
  • the electrolyte optionally also includes other additives.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain properties of the battery, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.
  • a sodium ion battery which includes the electrolyte of the present application.
  • a sodium-ion battery typically includes a positive electrode plate, a negative electrode plate, an electrolyte and a separator.
  • active ions are inserted and detached back and forth between the positive and negative electrodes.
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • 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 ions to pass through.
  • the positive electrode sheet 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 can be a conductive carbon sheet, metal foil, carbon-coated metal foil, porous metal plate or composite current collector, wherein the conductive carbon material of the conductive carbon sheet can be superconducting carbon, acetylene black, carbon One or more of black, Ketjen black, carbon dots, carbon nanotubes, graphite, graphene and carbon nanofibers, the metal materials of metal foil, carbon-coated metal foil and porous metal plate can be independently selected from At least one of copper, aluminum, nickel and stainless steel.
  • the composite current collector can be a composite current collector formed by combining a metal foil and a polymer base film.
  • the positive electrode current collector is, for example, one or more of copper foil, aluminum foil, nickel foil, stainless steel foil, stainless steel mesh, and carbon-coated aluminum foil.
  • Aluminum foil is preferably used.
  • the cathode active material may be a cathode active material known in the art for sodium ion batteries.
  • the positive active material may include at least one of a sodium transition metal oxide, a polyanionic compound, and a Prussian blue compound.
  • this application is not limited to these materials.
  • the transition metal in the sodium transition metal oxide, may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce.
  • the sodium transition metal oxide is, for example, Na x MO 2 , where M is one or more of Ti, V, Mn, Co, Ni, Fe, Cr and Cu, 0 ⁇ x ⁇ 1.
  • the polyanionic compound may be a type of compound having sodium ions, transition metal ions, and tetrahedral (YO 4 ) n- anion units.
  • the transition metal can be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce;
  • Y can be at least one of P, S and Si;
  • n represents (YO 4 ) n -valency.
  • Polyanionic compounds may also be compounds having sodium ions, transition metal ions, tetrahedral (YO 4 ) n- anion units and halogen anions.
  • the transition metal can be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce;
  • Y can be at least one of P, S and Si, n represents (YO 4 )
  • the valence state of n- ; the halogen can be at least one of F, Cl and Br.
  • Polyanionic compounds may also be a class of compounds having sodium ions, tetrahedral (YO 4 ) n- anion units, polyhedral units (ZO y ) m+ , and optionally halogen anions.
  • Y can be at least one of P, S and Si
  • n represents the valence state of (YO 4 ) n-
  • Z represents a transition metal, which can be Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V , Zr and Ce
  • m represents the valence state of (ZO y ) m+
  • the halogen can be at least one of F, Cl and Br.
  • polyanionic compounds are NaFePO 4 , Na 3 V 2 (PO 4 ) 3 , NaM'PO 4 F (M' is one or more of V, Fe, Mn and Ni) and Na 3 (VO y ) At least one of 2 (PO 4 ) 2 F 3-2y (0 ⁇ y ⁇ 1).
  • Prussian blue compounds may be compounds containing sodium ions, transition metal ions and cyanide ions (CN - ).
  • the transition metal may be at least one of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce.
  • the Prussian blue compound is, for example, Na a Me b Me' c (CN) 6 , where Me and Me' are each independently at least one of Ni, Cu, Fe, Mn, Co and Zn, 0 ⁇ a ⁇ 2, 0 ⁇ b ⁇ 1, 0 ⁇ c ⁇ 1.
  • the positive electrode film layer optionally further includes a binder.
  • the binder may be polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid (PAA), polyvinyl alcohol (PVA), ethylene-vinyl acetate copolymer (EVA), At least one of styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), sodium alginate (SA), polymethacrylic acid (PMA) and carboxymethyl chitosan (CMCS).
  • the positive electrode film layer optionally further includes a conductive agent.
  • the conductive agent may be one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphite, 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 includes, but is not limited to: copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam or a composite current collector covered with conductive metal.
  • the negative active material includes graphite, sodium metal, sodium alloy, carbon black (hard carbon or soft carbon), silicon material, silicon oxide material, tin material, tin oxide material or silicon carbon composite material. At least one.
  • the negative active material includes graphite.
  • the graphite may be artificial graphite or natural graphite.
  • sodium ions and ether compound molecules can undergo a highly reversible co-intercalation reaction in graphite to form a stable graphite ternary intercalation compound, which is beneficial to improving the initial Coulombic efficiency and rate performance of the battery.
  • the negative electrode film layer optionally further includes a binder.
  • the binder includes polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymer Materials, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylic (ester) styrene-butadiene rubber, epoxy resin or nylon, etc.
  • the negative electrode film layer optionally further includes a conductive agent.
  • the conductive agent can be selected from natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, metal powder, metal fiber, copper, nickel, aluminum, silver or polyphenylene derivatives, etc.
  • 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
  • a separator membrane is further included in the sodium ion battery.
  • isolation membrane 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.
  • a sodium-ion 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 sodium ion battery can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of sodium-ion batteries can 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 sodium ion 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 sodium ion battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.
  • sodium-ion batteries can be assembled into battery modules, and the number of sodium-ion batteries contained in the battery module can be one or more. The specific number can be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG. 3 is a battery module 4 as an example.
  • a plurality of sodium ion batteries 5 may be arranged in sequence along the length direction of the battery module 4 .
  • the plurality of sodium ion batteries 5 can be fixed by fasteners.
  • the battery module 4 may also include a housing having an accommodation space in which a plurality of sodium ion batteries 5 are accommodated.
  • 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 sodium-ion battery, battery module, or battery pack provided by the present application.
  • the sodium ion battery, battery module, or battery pack can be used as a power source for the electrical device, or 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 sodium-ion 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.
  • battery packs or battery modules can be used.
  • the device may be a mobile phone, a tablet, a laptop, etc.
  • the device is usually required to be thin and light, and a sodium-ion battery can be used as the power source.
  • SBR styrene-butadiene rubber
  • the sodium metal alloy active material is 0.025g/1540.25mm2.
  • Capacity retention rate discharge capacity after n cycles (Cdn)/discharge capacity in the first cycle (Cd1).
  • the sodium-ion battery was disassembled in an argon atmosphere glove box (H 2 O ⁇ 0.1ppm, O 2 ⁇ 0.1ppm).
  • the surface morphology of the negative electrode sheet was visually observed through an optical microscope to determine whether there was any Sodium dendrite formation. If the negative electrode piece has no white spots, it is judged that there is no sodium dendrites. If there are sporadic white spots on the negative electrode piece, it is judged that the sodium dendrites are mild. If there are obviously more white spots on the negative electrode piece, it is judged that the sodium dendrites are serious.
  • Comparative Examples 1-5 do not contain ether solvents, sodium borate compounds and borate ester compounds at the same time, or the proportion of ether solvents in the total solvent is too low, and sodium branches appear after recycling. Crystal, and the battery volume has a relatively obvious expansion, and the capacity retention rate and first Coulombic efficiency of the battery are lower than those of the embodiments of the present application.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Materials Engineering (AREA)
  • Secondary Cells (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

本申请提供一种钠离子电池电解液，其中，所述电解液包含作为溶剂的醚类化合物、作为钠盐的硼酸钠类化合物和作为添加剂的硼酸酯类化合物，所述醚类化合物在所述电解液的全部溶剂中所占的比例为50重量％以上。所述电解液能够抑制电池体积膨胀和钠枝晶生长。本申请还提供包含该电解液的钠离子电池、电池模块、电池包及用电装置。

Description

钠离子电池电解液、包含其的钠离子电池及用电装置 技术领域
本申请涉及二次电池技术领域，尤其涉及一种钠离子电池的电解液和包含其的钠离子电池，以及包含该钠离子电池的电池模块、电池包和用电装置。
背景技术
近年来，锂离子电池的需求量日益增加，但有限的锂资源限制了锂离子电池的可持续发展。作为锂离子电池的重要补充，钠离子电池受到越来越多的关注。
钠离子电池在经过多次充放电循环后，有可能产生电池的体积膨胀，还有可能在电极上发生钠枝晶生长。电池的体积膨胀和钠枝晶生长会导致电池的库伦效率降低、循环寿命短，甚至影响电池的安全性能。现有的钠离子电池在上述方面仍有待改进。
发明内容
本申请是鉴于上述课题而进行的，其目的在于，降低钠离子电池在循环后的体积膨胀并抑制电极上的钠枝晶形成。
为了达到上述目的，本申请的第一方面提供了一种钠离子电池电解液，其中，所述电解液包含作为溶剂的醚类化合物、作为钠盐的硼酸钠类化合物和作为添加剂的硼酸酯类化合物，所述醚类化合物在所述电解液的全部溶剂中所占的比例为50重量％以上。
由此，本申请通过该电解液中特定的组合，能够抑制钠离子电池在循环后的体积膨胀和钠枝晶生长。因此，包含所述电解液的钠离子电池具有较好的库伦效率和循环性能。
在任意实施方式中，所述硼酸酯类化合物具有下述式(I)的结构：
Figure PCTCN2022104914-appb-000001
其中，R 1、R 2、R 3相同或不同并且选自烷基、芳基、烷基甲硅烷基、烯基、炔基、氰基烷基，上述基团任选被卤素取代，可选地，所述卤素为氟；可选地，R 1、R 2、R 3相同或不同并且选自C1-C6烷基、C1-C6卤代烷基、C6-C12芳基、C6-C12卤代芳基、C1-C6烷基甲硅烷基、C2-C6烯基、C2-C6炔基、氰基-C1-C6烷基；可选地，R 1、R 2和R 3中的至少一者代表C1-C6氟代烷基或C6-C12氟代芳基；
可选地，所述硼酸酯类化合物为选自硼酸三甲酯、硼酸三乙酯、硼酸三丙酯、硼酸三丁酯、硼酸三(2,2,2-三氟乙基)酯、三(六氟异丙基)硼酸酯、三苯基硼酸酯、三(三甲基硅基)硼酸酯、三(三乙基硅基)硼酸酯、三(五氟苯基)硼酸酯、(二正丁基)(乙烯基)硼酸酯、(二正丁基)(炔丙基)硼酸酯、三(2-氰乙基)硼酸酯中的一种或多种；进一步可选地，所述硼酸酯类化合物为选自硼酸三甲酯、硼酸三乙酯、硼酸三丙酯、硼酸三丁酯中的一种或多种。尤其是具有较小分子的硼酸酯类化合物较为有利。
通过进一步选择硼酸酯类化合物，能够进一步降低电池体积膨胀，改善电池的循环性能和库伦效率。
在任意实施方式中，所述硼酸酯类化合物的含量为0.5重量％至10重量％，可选地为1重量％至5重量％，例如2重量％，基于所述电解液的总重量计。
通过进一步选择硼酸酯类化合物的含量，能够进一步降低电池体积膨胀，改善电池的循环性能和库伦效率。
在任意实施方式中，所述硼酸钠类化合物为选自二氟硼酸钠和具有下述式(II)结构的化合物中的一种或多种
Figure PCTCN2022104914-appb-000002
其中，R 4、R 5、R 6、R 7各自独立地选自卤素原子、烷基、氰基、烷氧基、芳基，其中所述烷基、烷氧基和芳基任选被卤素取代，可选地，所述卤素为氟；或者R 4与R 5一起和/或R 6与R 7一起形成式(a)的结构
Figure PCTCN2022104914-appb-000003
可选地，R 4、R 5、R 6、R 7各自独立地选自卤素原子、C1-C6烷基、C1-C6卤代烷基、氰基、C1-C6烷氧基、苯基，或者R 4与R 5一起和/或R 6与R 7一起形成式(a)的结构；可选地，R 4、R 5、R 6、R 7中的至少一者代表C1-C6氟代烷基；
可选地，所述硼酸钠类化合物选自二氟硼酸钠、四氟硼酸钠、二草酸硼酸钠、二氟草酸硼酸钠、四苯硼酸钠、四氰基硼酸钠、四(三氟甲基)硼酸钠、双(三氟甲基)二氟硼酸钠、五氟乙基三氟硼酸钠、二氰基草酸硼酸钠、甲氧基三氰基硼酸钠、乙氧基三氰基硼酸钠、四甲氧基硼酸钠、四乙氧基硼酸钠、氰基三(2,2,2三氟乙基)硼酸钠中的一种或多种。
通过进一步选择硼酸钠类化合物，能够进一步降低电池体积膨胀，改善电池的循环性能和库伦效率。
在任意实施方式中，所述硼酸钠类化合物的浓度为0.5M-8M，可选地为1M-4M，基于所述电解液的总体积计。
通过进一步选择硼酸钠类化合物的含量，能够进一步降低电池体积膨胀，改善电池的循环性能和库伦效率。
在任意实施方式中，所述醚类化合物为选自碳原子数为4-20的脂肪族醚、碳原子数为3-8的脂环族醚、碳原子数为7-20的芳族醚、冠醚中的一种或多种；可选地，所述醚类化合物为选自乙二醇二甲醚、乙二醇二乙醚、二乙二醇二甲醚、三乙二醇二甲醚、四乙二醇二甲醚、1,3-二氧戊环、四氢呋喃、甲基四氢呋喃、二苯醚、冠醚中的一种或多种；进一步可选地，所述醚类化合物为选自乙二醇二甲醚、乙二醇二乙醚、二乙二醇二甲醚中的一种或多种。
通过进一步选择醚类化合物，有利于抑制钠枝晶生长和电池体积膨胀。
在任意实施方式中，所述醚类化合物在所述电解液的全部溶剂中所占的比例为60重量％以上，可选地为80重量％以上，进一步可选地，所述溶剂由醚类化合物组成。
通过控制醚类化合物在电解液的全部溶剂中所占的比例，有利于抑制钠枝晶生长和电池体积膨胀。
本申请的第二方面还提供一种钠离子电池，其包括本申请第一方面的电解液。
本申请的第三方面提供一种电池模块，包括本申请的第二方面的钠离子电池。
本申请的第四方面提供一种电池包，包括本申请的第三方面的电池模块。
本申请的第五方面提供一种用电装置，包括选自本申请的第二方面的钠离子电池、本申请的第三方面的电池模块或本申请的第四方面的电池包中的至少一种。
附图说明
图1是本申请一实施方式的钠离子电池的示意图。
图2是图1所示的本申请一实施方式的钠离子电池的分解图。
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钠离子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钠离子电池；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钠离子电池电解液及其制造方法、钠离子电池、电池模块、电池包和电学装置的实施方式。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)。
钠离子电池在经过多次充放电循环后，有可能产生电池的体积膨胀，还有可能在电极上发生钠枝晶生长。电池的体积膨胀和钠枝晶生长会导致电池的库伦效率降低、循环寿命短，甚至影响电池的安全性能。因此，对于钠离子电池，有降低其循环后的体积膨胀以及抑制钠枝晶形成的需求。
本申请人发现，当钠离子电池的电解液中使用醚类化合物作为溶剂，并且在电解液中同时包含硼酸钠类化合物和硼酸酯类化合物时，所得钠离子电池的体积膨胀显著降低，并抑制了钠枝晶生长。
因此，本申请的一个实施方式中，本申请提供了一种钠离子电池电解液，其中，所述电解液包含作为溶剂的醚类化合物、作为钠盐的硼酸钠类化合物和作为添加剂的硼酸酯类化合物，所述醚类化合物在所述电解液的全部溶剂中所占的比例为50重量％以上。
虽然机理尚不明确，但本申请人意外地发现：本申请通过在电解液的溶剂中包含大量醚类化合物，并且在电解液中加入硼酸钠类化合物和硼酸酯类化合物，能够使钠离子电池在多次循环后的体积膨胀显著降低，且电极上不发生钠枝晶生长。不希望囿于理论，推测是上述物质组合导致在电极表面形成了富含无机硼酸盐的固态电解质界面(SEI)层，该SEI层具有较高的机械稳定性，从而抑制了体积膨胀 和钠枝晶生长。因此，包含所述电解液的钠离子电池具有较好的库伦效率和循环性能。
在一些实施方式中，所述硼酸酯类化合物具有下述式(I)的结构：
Figure PCTCN2022104914-appb-000004
其中，R 1、R 2、R 3相同或不同并且选自烷基、芳基、烷基甲硅烷基、烯基、炔基、氰基烷基，上述基团任选被卤素取代，可选地，所述卤素为氟；可选地，R 1、R 2、R 3相同或不同并且选自C1-C6烷基、C1-C6卤代烷基、C6-C12芳基、C6-C12卤代芳基、C1-C6烷基甲硅烷基、C2-C6烯基、C2-C6炔基、氰基-C1-C6烷基；可选地，R 1、R 2和R 3中的至少一者代表C1-C6氟代烷基或C6-C12氟代芳基；
可选地，所述硼酸酯类化合物为选自硼酸三甲酯、硼酸三乙酯、硼酸三丙酯、硼酸三丁酯、硼酸三(2,2,2-三氟乙基)酯、三(六氟异丙基)硼酸酯、三苯基硼酸酯、三(三甲基硅基)硼酸酯、三(三乙基硅基)硼酸酯、三(五氟苯基)硼酸酯、(二正丁基)(乙烯基)硼酸酯、(二正丁基)(炔丙基)硼酸酯、三(2-氰乙基)硼酸酯中的一种或多种；进一步可选地，所述硼酸酯类化合物为选自硼酸三甲酯、硼酸三乙酯、硼酸三丙酯、硼酸三丁酯中的一种或多种。尤其是具有较小分子的硼酸酯类化合物较为有利。
通过进一步选择硼酸酯类化合物，能够进一步降低电池体积膨胀，改善电池的循环性能和库伦效率。尤其是硼酸酯类化合物含有氟时，SEI层中的NaF可进一步为负极提供保护。
在一些实施方式中，所述硼酸酯类化合物的含量为0.5重量％至10重量％，可选地为1重量％至5重量％，例如2重量％至3重量％，基于所述电解液的总重量计。
通过进一步选择硼酸酯类化合物的含量，能够进一步降低电池体积膨胀，改善电池的循环性能和库伦效率。
在一些实施方式中，所述硼酸钠类化合物为选自二氟硼酸钠和具有下述式(II)结构的化合物中的一种或多种
Figure PCTCN2022104914-appb-000005
其中，R 4、R 5、R 6、R 7各自独立地选自卤素原子、烷基、氰基、烷氧基、芳基，其中所述烷基、烷氧基和芳基任选被卤素取代，可选地，所述卤素为氟；或者R 4与R 5一起和/或R 6与R 7一起形成式(a)的结构
Figure PCTCN2022104914-appb-000006
可选地，R 4、R 5、R 6、R 7各自独立地选自卤素原子、C1-C6烷基、C1-C6卤代烷基、氰基、C1-C6烷氧基、苯基，或者R 4与R 5一起和/或R 6与R 7一起形成式(a)的结构；可选地，R 4、R 5、R 6、R 7中的至少一者代表C1-C6氟代烷基；
可选地，所述硼酸钠类化合物选自二氟硼酸钠、四氟硼酸钠、二草酸硼酸钠、二氟草酸硼酸钠、四苯硼酸钠、四氰基硼酸钠、四(三氟甲基)硼酸钠、双(三氟甲基)二氟硼酸钠、五氟乙基三氟硼酸钠、二氰基草酸硼酸钠、甲氧基三氰基硼酸钠、乙氧基三氰基硼酸钠、四甲氧基硼酸钠、四乙氧基硼酸钠、氰基三(2,2,2三氟乙基)硼酸钠中的一种或多种。
通过进一步选择硼酸钠类化合物，能够进一步降低电池体积膨胀，改善电池的循环性能和库伦效率。尤其是硼酸钠类化合物含有氟时，SEI层中的NaF可进一步为负极提供保护。
在一些实施方式中，所述硼酸钠类化合物的浓度为0.5M-8M，可选地为1M-4M，例如1M-2M，例如1.5M，基于所述电解液的总体积计。
通过进一步选择硼酸钠类化合物的含量，能够进一步降低电池体积膨胀，改善电池的循环性能和库伦效率。
在一些实施方式中，所述醚类化合物为选自碳原子数为4-20的脂肪族醚、碳原子数为3-8的脂环族醚、碳原子数为7-20的芳族醚、冠醚中的一种或多种；可选地，所述醚类化合物为选自乙二醇二甲醚、乙二醇二乙醚、二乙二醇二甲醚、三乙二醇二甲醚、四乙二醇二甲醚、1,3-二氧戊环、四氢呋喃、甲基四氢呋喃、二苯醚、冠醚中的一种或多种；进一步可选地，所述醚类化合物为选自乙二醇二甲醚、乙二醇二乙醚、二乙二醇二甲醚中的一种或多种。
通过进一步选择醚类化合物，可以在钠金属负极、碳材料负极及其他非碳材料负极表面构建稳定的电极/电解液界面，形成稳定的固态电解质界面(SEI)，减小电化学极化，从而有利于抑制钠枝晶生长和电池体积膨胀。
在一些实施方式中，所述醚类化合物在所述电解液的全部溶剂中所占的比例为60重量％以上，或70重量％以上，可选地为80重量％以上，例如为85重量％以上，或90重量％以上，或95重量％以上，或98重量％以上。进一步可选地，所述溶剂由醚类化合物组成。
通过控制醚类化合物在电解液的全部溶剂中所占的比例，能够在负极表面构建稳定的电极/电解液界面，形成稳定的固态电解质界面，有利于抑制钠枝晶生长和电池体积膨胀，并可进一步改善电池的循环性能和库伦效率。
如本领域技术人员可以理解的，钠离子电池中，电解液在正极极片和负极极片之间起到传导离子的作用。电解液包括电解质盐和溶剂。本申请的钠离子电池中，电解质盐为钠盐。
所述硼酸钠类化合物本身可作为电解质盐。在一些实施方式中，除所述硼酸钠类化合物之外，电解质盐可进一步包含选自NaClO 4、NaPF 6、NaBF 4、NaTFSI(双三氟甲磺酰亚胺钠)、NaFSI(双氟磺酰亚胺钠)中的一种或多种物质。在一些实施方式中，电解质盐的总摩尔浓度为0.5M至8M，可选地为1M至4M，基于电解液总体积计
在一些实施方式中，电解液的溶剂除醚类化合物之外，还包含选自碳酸亚乙酯、碳酸亚丙酯、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、 碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1,4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种溶剂。
在一些实施方式中，所述电解液还可选地包括其他添加剂。例如添加剂可以包括负极成膜添加剂、正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。
另外，以下适当参照附图对本申请的钠离子电池、电池模块、电池包和用电装置进行说明。
本申请的一个实施方式中，提供一种钠离子电池，其包括本申请的电解液。
通常情况下，钠离子电池包括正极极片、负极极片、电解液和隔离膜。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。电解液在正极极片和负极极片之间起到传导离子的作用。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，同时可以使离子通过。
[正极极片]
正极极片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，所述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，正极集流体可以采用导电碳片、金属箔材、涂炭金属箔材、多孔金属板或复合集流体，其中导电碳片的导电碳材质可以为超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨、石墨烯及碳纳米纤维中的一种或几种，金属箔材、涂炭金属箔材和多孔金属板的金属材质各自独立地可以选自铜、铝、镍及不锈钢中的至少一种。复合集流体可以为金属箔材与高分子基膜复合形成的复合集 流体。
正极集流体例如为铜箔、铝箔、镍箔、不锈钢箔、不锈钢网及涂炭铝箔中的一种或几种，优选采用铝箔。
在一些实施方式中，正极活性材料可采用本领域公知的用于钠离子电池的正极活性材料。作为示例，正极活性材料可包括钠过渡金属氧化物、聚阴离子型化合物和普鲁士蓝类化合物中的至少一种。但本申请并不限定于这些材料。
可选地，钠过渡金属氧化物中，过渡金属可以是Mn、Fe、Ni、Co、Cr、Cu、Ti、Zn、V、Zr及Ce中的至少一种。钠过渡金属氧化物例如为Na xMO 2，其中M为Ti、V、Mn、Co、Ni、Fe、Cr及Cu中的一种或几种，0＜x≤1。
可选地，聚阴离子型化合物可以是具有钠离子、过渡金属离子及四面体型(YO 4) n-阴离子单元的一类化合物。过渡金属可以是Mn、Fe、Ni、Co、Cr、Cu、Ti、Zn、V、Zr及Ce中的至少一种；Y可以是P、S及Si中的至少一种；n表示(YO 4) n-的价态。
聚阴离子型化合物还可以是具有钠离子、过渡金属离子、四面体型(YO 4) n-阴离子单元及卤素阴离子的一类化合物。过渡金属可以是Mn、Fe、Ni、Co、Cr、Cu、Ti、Zn、V、Zr及Ce中的至少一种；Y可以是P、S及Si中的至少一种，n表示(YO 4) n-的价态；卤素可以是F、Cl及Br中的至少一种。
聚阴离子型化合物还可以是具有钠离子、四面体型(YO 4) n-阴离子单元、多面体单元(ZO y) m+及可选的卤素阴离子的一类化合物。Y可以是P、S及Si中的至少一种，n表示(YO 4) n-的价态；Z表示过渡金属，可以是Mn、Fe、Ni、Co、Cr、Cu、Ti、Zn、V、Zr及Ce中的至少一种，m表示(ZO y) m+的价态；卤素可以是F、Cl及Br中的至少一种。
聚阴离子型化合物例如是NaFePO 4、Na 3V 2(PO 4) 3、NaM’PO 4F(M’为V、Fe、Mn及Ni中的一种或几种)及Na 3(VO y) 2(PO 4) 2F 3-2y(0≤y≤1)中的至少一种。
普鲁士蓝类化合物可以是具有钠离子、过渡金属离子及氰根离子 (CN -)的一类化合物。过渡金属可以是Mn、Fe、Ni、Co、Cr、Cu、Ti、Zn、V、Zr及Ce中的至少一种。普鲁士蓝类化合物例如为Na aMe bMe’ c(CN) 6，其中Me及Me’各自独立地为Ni、Cu、Fe、Mn、Co及Zn中的至少一种，0＜a≤2，0＜b＜1，0＜c＜1。
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，所述粘结剂可以为聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、聚丙烯酸(PAA)、聚乙烯醇(PVA)、乙烯-醋酸乙烯酯共聚物(EVA)、丁苯橡胶(SBR)、羧甲基纤维素(CMC)、海藻酸钠(SA)、聚甲基丙烯酸(PMA)及羧甲基壳聚糖(CMCS)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，所述导电剂可以为超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨、石墨烯及碳纳米纤维中的一种或几种。
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，负极集流体包括，但不限于：铜箔、镍箔、不锈钢箔、钛箔、泡沫镍、泡沫铜或覆有导电金属的复合集流体。
在一些实施方式中，所述负极活性材料包括石墨、钠金属、钠合金、碳黑(硬碳或软碳)、硅材料、硅氧材料、锡材料、锡氧材料或硅碳复合材料中的至少一种。
在一些实施方式中，负极活性材料包括石墨。所述石墨可以是人造石墨或天然石墨。针对石墨体系，钠离子和醚类化合物分子可以高 度可逆地在石墨中发生共插层反应，形成稳定的石墨三元插层化合物，从而有利于提高电池的初始库伦效率和倍率性能。
在一些实施方式中，负极膜层还可选地包括粘结剂。所述粘结剂包括聚乙烯醇、羧甲基纤维素、羟丙基纤维素、二乙酰基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚氟乙烯、含亚乙基氧的聚合物、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、聚偏1，1-二氟乙烯、聚乙烯、聚丙烯、丁苯橡胶、丙烯酸(酯)化的丁苯橡胶、环氧树脂或尼龙等。
在一些实施方式中，负极膜层还可选地包括导电剂。导电剂可选自天然石墨、人造石墨、碳黑、乙炔黑、科琴黑、碳纤维、金属粉、金属纤维、铜、镍、铝、银或聚亚苯基衍生物等。
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，钠离子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，钠离子电池可包括外包装。该外包装可用于封装上述电极组件及电解液。
在一些实施方式中，钠离子电池的外包装可以是硬壳，例如硬塑 料壳、铝壳、钢壳等。钠离子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。
本申请对钠离子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钠离子电池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。钠离子电池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，钠离子电池可以组装成电池模块，电池模块所含钠离子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，多个钠离子电池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钠离子电池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，多个钠离子电池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钠离子电池、电池模块、或电池包中的至少一种。所述钠离子电池、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钠离子电池、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钠离子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。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用钠离子电池作为电源。
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。
实施例1
【正极极片的制备】
将10重量份聚偏氟乙烯粘结剂充分溶解于N-甲基吡咯烷酮中，加入10重量份炭黑导电剂与80重量份Na 4Fe 3(PO 4) 2(P 2O 7)制成分散均匀的浆料。将浆料均匀涂敷在铝箔表面，然后转移到真空干燥箱中完全干燥。将得到的极片进行辊压，然后进行冲切，得到正极极片。 正极极片的负载量为0.3g/1540.25mm 2。
【负极极片的制备】
先将硬碳材料放入体积比为3∶1的浓硫酸与浓硝酸的混合溶液中搅拌4小时，用去离子水洗涤、过滤后放入烘箱中，在80℃条件下烘干。将经上述处理的碳材料和高分子聚合物SBR(丁苯橡胶)，以重量比95：5加到N-甲基吡咯烷酮中搅拌成均匀的浆料，将浆料涂覆在铜箔上并烘干即得到所用碳材料涂层，涂覆量0.010g/1540.25mm 2。
在氩气气氛下，将钠金属放入到不锈钢坩埚中加热至200℃使其完全融化，然后将钠铋合金组分粉末加入到液态钠金属中并充分搅拌2小时，确保金属粉末与钠金属液体均匀混合，冷却后即可得到钠金属合金活性物质，钠金属合金活性物质中铋的含量为5重量％。将钠金属合金活性物质通过冷压复合在碳材料涂层表面，得到负极极片，所述钠金属合金活性物质的负载量为0.025g/1540.25mm2。
【电解液的制备】
在氩气气氛手套箱中(H 2O<0.1ppm，O 2<0.1ppm)，将二氟草酸硼酸钠和硼酸三甲酯溶解于有机溶剂乙二醇二甲醚中，搅拌均匀，得到硼酸三甲酯浓度为2重量％，二氟草酸硼酸钠(NaDFOB)浓度为1.5mol/L的电解液，即实施例1的电解液。
【隔离膜】
以聚丙烯膜作为隔离膜。
【钠离子电池的制备】
将上述正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正、负极极片之间，加入上述电解液组装成叠片电池。
实施例2-33
除了如表1所示改变电解液配方以外，实施例2-33的其他步骤与实施例1相同。
实施例34
除了负极极片的制备以如下方式进行之外，其他步骤与实施例1 相同：
将5重量份羧甲基纤维素钠粘结剂充分溶解于去离子水中，加入95重量份石墨制成分散均匀的浆料。将浆料均匀涂敷在铜箔表面，然后转移到真空干燥箱中完全干燥。将得到的极片进行辊压，然后进行冲切，得到负极极片。负极极片的负载量为0.035g/1540.25mm 2。
对比例1-5
除了如表1所示改变电解液配方以外，对比例1-5的其他步骤与实施例1相同。
电池性能测试
【库伦效率】
将钠离子电池在25℃下以1/3C的恒定电流充电至3.65V，之后以3.65V恒压充电至电流降到0.05C，得到首次充电容量(Cc1)；再以1/3C的恒定电流放电至2.5V，得到首次放电容量(Cd1)。按照下式计算钠离子电池库伦效率：
钠离子电池库伦效率＝首次放电容量(Cd1)/首次充电容量(Cc1)
【容量保持率】
将钠离子电池在25℃下以1C的恒定电流充电至3.65V，之后以3.65V恒压充电至电流降到0.05C，再以1C的恒定电流放电至2.5V，得到首圈放电容量(Cd1)；如此反复充放电至第n圈，得到钠离子电池循环n圈后的放电容量，记为Cdn。按照下式计算钠离子电池容量保持率：
容量保持率＝循环n圈后的放电容量(Cdn)/首圈放电容量(Cd1)。
【体积膨胀】
将钠离子电池没入盛有硅油的容器中，记录此时硅油液面的高度；使电池充放电循环经过指定的圈数后，硅油在电池体积形变压力的作用下液面上升，观察记录此时容器中硅油液面的高度。由电池充放电循环之前和之后硅油液面的高度得到液面上升的高度差，计算得出电池循环产生的膨胀体积。
【钠枝晶】
将循环200圈后的钠离子电池在氩气气氛手套箱中(H 2O<0.1ppm，O 2<0.1ppm)进行拆解，通过光学显微镜目视观察负极极片表面形貌，确定是否有钠枝晶生成。负极极片无白点判定为钠枝晶情况无、负极极片有零星白点判定为钠枝晶情况轻微、负极极片有明显较多白点判定为钠枝晶情况严重。
实施例1～34、对比例1～5的电解液组成和电池性能测试结果如下述表1所示。
表1
Figure PCTCN2022104914-appb-000007
Figure PCTCN2022104914-appb-000008
Figure PCTCN2022104914-appb-000009
根据上述结果可知，实施例1-34通过使用包含作为溶剂的醚类化合物、作为钠盐的硼酸钠类化合物和作为添加剂的硼酸酯类化合物的电解液，电池在多次循环后的体积膨胀很小，且电极上未出现钠枝晶，电池的容量保持率和首次库伦效率较高。尤其是，当硼酸酯的含量在1-5重量％、或硼酸钠含量在1-4M的范围时，电池的体积膨胀进一步减小，容量保持率和首次库伦效率进一步提高。
而相对于此，对比例1-5未同时包含醚类溶剂、硼酸钠类化合物和硼酸酯类化合物，或者醚类溶剂在总溶剂中所占比例过低，其在循环后均出现了钠枝晶，且电池体积有较明显的膨胀，电池的容量保持率和首次库伦效率低于本申请实施例。
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 (12)

  1. 一种钠离子电池电解液，其中，所述电解液包含作为溶剂的醚类化合物、作为钠盐的硼酸钠类化合物和作为添加剂的硼酸酯类化合物，所述醚类化合物在所述电解液的全部溶剂中所占的比例为50重量％以上。
  2. 根据权利要求1所述的钠离子电池电解液，其中，所述硼酸酯类化合物具有下述式(I)的结构：
    Figure PCTCN2022104914-appb-100001
    其中，R 1、R 2、R 3相同或不同并且选自烷基、芳基、烷基甲硅烷基、烯基、炔基、氰基烷基，上述基团任选被卤素取代，可选地，所述卤素为氟；可选地，R 1、R 2、R 3相同或不同并且选自C1-C6烷基、C1-C6卤代烷基、C6-C12芳基、C6-C12卤代芳基、C1-C6烷基甲硅烷基、C2-C6烯基、C2-C6炔基、氰基-C1-C6烷基；可选地，R 1、R 2和R 3中的至少一者代表C1-C6氟代烷基或C6-C12氟代芳基；
    可选地，所述硼酸酯类化合物为选自硼酸三甲酯、硼酸三乙酯、硼酸三丙酯、硼酸三丁酯、硼酸三(2,2,2-三氟乙基)酯、三(六氟异丙基)硼酸酯、三苯基硼酸酯、三(三甲基硅基)硼酸酯、三(三乙基硅基)硼酸酯、三(五氟苯基)硼酸酯、(二正丁基)(乙烯基)硼酸酯、(二正丁基)(炔丙基)硼酸酯、三(2-氰乙基)硼酸酯中的一种或多种；进一步可选地，所述硼酸酯类化合物为选自硼酸三甲酯、硼酸三乙酯、硼酸三丙酯、硼酸三丁酯中的一种或多种。
  3. 根据权利要求1或2所述的钠离子电池电解液，其中，所述硼酸酯类化合物的含量为0.5重量％至10重量％，可选地为1重量％至5重量％，基于所述电解液的总重量计。
  4. 根据权利要求1至3中任一项所述的钠离子电池电解液，其中，所述硼酸钠类化合物为选自二氟硼酸钠和具有下述式(II)结构的化合物中的一种或多种
    Figure PCTCN2022104914-appb-100002
    其中，R 4、R 5、R 6、R 7各自独立地选自卤素原子、烷基、氰基、烷氧基、芳基，其中所述烷基、烷氧基和芳基任选被卤素取代，可选地，所述卤素为氟；或者R 4与R 5一起和/或R 6与R 7一起形成式(a)的结构
    Figure PCTCN2022104914-appb-100003
    可选地，R 4、R 5、R 6、R 7各自独立地选自卤素原子、C1-C6烷基、C1-C6卤代烷基、氰基、C1-C6烷氧基、苯基，或者R 4与R 5一起和/或R 6与R 7一起形成式(a)的结构；可选地，R 4、R 5、R 6、R 7中的至少一者代表C1-C6氟代烷基；
    可选地，所述硼酸钠类化合物选自二氟硼酸钠、四氟硼酸钠、二草酸硼酸钠、二氟草酸硼酸钠、四苯硼酸钠、四氰基硼酸钠、四(三氟甲基)硼酸钠、双(三氟甲基)二氟硼酸钠、五氟乙基三氟硼酸钠、二氰基草酸硼酸钠、甲氧基三氰基硼酸钠、乙氧基三氰基硼酸钠、四甲氧基硼酸钠、四乙氧基硼酸钠、氰基三(2,2,2三氟乙基)硼酸钠中的一种或多种。
  5. 根据权利要求1至4中任一项所述的钠离子电池电解液，其中，所述硼酸钠类化合物的浓度为0.5M-8M，可选地为1M-4M，基于所述电解液的总体积计。
  6. 根据权利要求1至5中任一项所述的钠离子电池电解液，其 中，所述醚类化合物为选自碳原子数为4-20的脂肪族醚、碳原子数为3-8的脂环族醚、碳原子数为7-20的芳族醚、冠醚中的一种或多种；可选地，所述醚类化合物为选自乙二醇二甲醚、乙二醇二乙醚、二乙二醇二甲醚、三乙二醇二甲醚、四乙二醇二甲醚、1,3-二氧戊环、四氢呋喃、甲基四氢呋喃、二苯醚、冠醚中的一种或多种；进一步可选地，所述醚类化合物为选自乙二醇二甲醚、乙二醇二乙醚、二乙二醇二甲醚中的一种或多种。
  7. 根据权利要求1至6中任一项所述的钠离子电池电解液，其中，所述醚类化合物在所述电解液的全部溶剂中所占的比例为60重量％以上，可选地为80重量％以上，进一步可选地，所述溶剂由醚类化合物组成。
  8. 一种钠离子电池，其特征在于，包括权利要求1至7中任一项所述的电解液。
  9. 根据权利要求8所述的钠离子电池，其中，所述负极中的负极活性材料包括石墨。
  10. 一种电池模块，其特征在于，包括权利要求8或9所述的钠离子电池。
  11. 一种电池包，其特征在于，包括权利要求10所述的电池模块。
  12. 一种用电装置，其特征在于，包括选自权利要求8或9所述的钠离子电池、权利要求10所述的电池模块或权利要求11所述的电池包中的至少一种。
PCT/CN2022/104914 2022-07-11 2022-07-11 钠离子电池电解液、包含其的钠离子电池及用电装置 Ceased WO2024011355A1 (zh)

Priority Applications (6)

Application Number Priority Date Filing Date Title
CN202280090970.8A CN118648152A (zh) 2022-07-11 2022-07-11 钠离子电池电解液、包含其的钠离子电池及用电装置
JP2024566429A JP2025517831A (ja) 2022-07-11 2022-07-11 ナトリウムイオン電池の電解液、それを含むナトリウムイオン電池及び電力消費装置
PCT/CN2022/104914 WO2024011355A1 (zh) 2022-07-11 2022-07-11 钠离子电池电解液、包含其的钠离子电池及用电装置
EP22950486.5A EP4517902A4 (en) 2022-07-11 2022-07-11 SODIUM-ION BATTERY ELECTROLYTE, SODIUM-ION BATTERY CONTAINING IT, AND ELECTRICAL DEVICE
KR1020247038128A KR20250004289A (ko) 2022-07-11 2022-07-11 나트륨 이온 전지 전해액, 이를 포함하는 나트륨 이온 전지 및 전기 장치
US18/953,118 US20250079521A1 (en) 2022-07-11 2024-11-20 Sodium-ion battery electrolytic solution, sodium-ion battery including same, and electrical device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2022/104914 WO2024011355A1 (zh) 2022-07-11 2022-07-11 钠离子电池电解液、包含其的钠离子电池及用电装置

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US18/953,118 Continuation US20250079521A1 (en) 2022-07-11 2024-11-20 Sodium-ion battery electrolytic solution, sodium-ion battery including same, and electrical device

Publications (1)

Publication Number Publication Date
WO2024011355A1 true WO2024011355A1 (zh) 2024-01-18

Family

ID=89535118

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/104914 Ceased WO2024011355A1 (zh) 2022-07-11 2022-07-11 钠离子电池电解液、包含其的钠离子电池及用电装置

Country Status (6)

Country Link
US (1) US20250079521A1 (zh)
EP (1) EP4517902A4 (zh)
JP (1) JP2025517831A (zh)
KR (1) KR20250004289A (zh)
CN (1) CN118648152A (zh)
WO (1) WO2024011355A1 (zh)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN119481295B (zh) * 2024-11-14 2025-10-28 孝感楚能新能源创新科技有限公司 一种钠离子电池电解液及其制备方法和应用

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113140723A (zh) * 2021-03-02 2021-07-20 复旦大学 一种基于金属铋负极的宽温钠离子电池
CN113809398A (zh) * 2021-08-12 2021-12-17 东莞市创明电池技术有限公司 电解液添加剂、电解液和钠二次电池
CN113937342A (zh) * 2021-09-20 2022-01-14 复旦大学 基于铁基聚阴离子型正极与锡碳负极的宽温钠离子电池
CN113937336A (zh) * 2021-09-20 2022-01-14 复旦大学 基于磷酸铁锂正极与锡碳负极的宽温混合离子电池
CN114243005A (zh) * 2021-12-18 2022-03-25 复旦大学 基于铁基聚阴离子型正极与碳基负极的宽温钠离子电池

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107565158B (zh) * 2017-08-29 2020-01-14 深圳中科瑞能实业有限公司 钠离子电池用电解液、制备方法及包含该钠离子电池用电解液的钠离子电池
GB202204201D0 (en) * 2022-03-24 2022-05-11 Faradion Ltd Electrolyte compositions

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113140723A (zh) * 2021-03-02 2021-07-20 复旦大学 一种基于金属铋负极的宽温钠离子电池
CN113809398A (zh) * 2021-08-12 2021-12-17 东莞市创明电池技术有限公司 电解液添加剂、电解液和钠二次电池
CN113937342A (zh) * 2021-09-20 2022-01-14 复旦大学 基于铁基聚阴离子型正极与锡碳负极的宽温钠离子电池
CN113937336A (zh) * 2021-09-20 2022-01-14 复旦大学 基于磷酸铁锂正极与锡碳负极的宽温混合离子电池
CN114243005A (zh) * 2021-12-18 2022-03-25 复旦大学 基于铁基聚阴离子型正极与碳基负极的宽温钠离子电池

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP4517902A4 *

Also Published As

Publication number Publication date
US20250079521A1 (en) 2025-03-06
EP4517902A4 (en) 2025-10-29
JP2025517831A (ja) 2025-06-11
EP4517902A1 (en) 2025-03-05
KR20250004289A (ko) 2025-01-07
CN118648152A (zh) 2024-09-13

Similar Documents

Publication Publication Date Title
CN116231091B (zh) 锂二次电池用电解液、二次电池和用电装置
WO2023050414A1 (zh) 二次电池及包含其的电池模块、电池包和用电装置
WO2023004819A1 (zh) 二次电池与含有该二次电池的电池模块、电池包和用电装置
WO2021023131A1 (zh) 电解液、锂离子电池及装置
WO2023230859A1 (zh) 二次电池及其制备方法、电池模块、电池包和用电装置
WO2023216139A1 (zh) 二次电池及其制备方法、电池模块、电池包和用电装置
WO2023044934A1 (zh) 二次电池、电池模块、电池包以及用电装置
WO2023060554A1 (zh) 电解液、二次电池和用电装置
WO2023169096A1 (zh) 正极活性材料、二次电池、电池模块、电池包和用电装置
WO2023130310A1 (zh) 电解液、二次电池和用电装置
WO2024230127A1 (zh) 电解液、锂二次电池及用电装置
WO2023225799A1 (zh) 二次电池以及包含其的电池模块、电池包及用电装置
CN116053469B (zh) 正极活性材料、正极极片、二次电池和用电装置
WO2023050406A1 (zh) 锂离子电池及包含其的电池模块、电池包和用电装置
EP4672410A1 (en) ELECTROLYTE, SECONDARY BATTERY AND ELECTRICAL DEVICE
US20250079521A1 (en) Sodium-ion battery electrolytic solution, sodium-ion battery including same, and electrical device
WO2023082924A1 (zh) 极片、锂离子电池、电池模块、电池包及用电装置
WO2024007138A1 (zh) 二次电池、电池模块、电池包及用电装置
US20250079520A1 (en) Electrolyte solution for sodium-ion battery, secondary battery, battery module, battery pack, and electrical apparatus
WO2023216029A1 (zh) 二次电池、电池模组、电池包及用电装置
WO2023102917A1 (zh) 负极活性材料及其制备方法、二次电池、电池模组、电池包、用电装置
JP7476419B2 (ja) 正極ペースト、正極シート、リチウムイオン電池、電池モジュール、電池パックおよび電力使用装置
WO2024007143A1 (zh) 二次电池、电池模块、电池包及用电装置
WO2023193230A1 (zh) 电解液、二次电池、电池模块、电池包和用电装置
WO2023216130A1 (zh) 一种电解液、二次电池、电池模块、电池包和用电装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22950486

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 202280090970.8

Country of ref document: CN

WWE Wipo information: entry into national phase

Ref document number: 2024566429

Country of ref document: JP

ENP Entry into the national phase

Ref document number: 20247038128

Country of ref document: KR

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 1020247038128

Country of ref document: KR

WWE Wipo information: entry into national phase

Ref document number: 2022950486

Country of ref document: EP

ENP Entry into the national phase

Ref document number: 2022950486

Country of ref document: EP

Effective date: 20241124

NENP Non-entry into the national phase

Ref country code: DE