WO2023198004A1 - Électrolyte de batterie et batterie au lithium-ion le comprenant - Google Patents

Électrolyte de batterie et batterie au lithium-ion le comprenant Download PDF

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Publication number
WO2023198004A1
WO2023198004A1 PCT/CN2023/087373 CN2023087373W WO2023198004A1 WO 2023198004 A1 WO2023198004 A1 WO 2023198004A1 CN 2023087373 W CN2023087373 W CN 2023087373W WO 2023198004 A1 WO2023198004 A1 WO 2023198004A1
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WO
WIPO (PCT)
Prior art keywords
lithium
electrolyte
carbonate
electrolyte solution
ion battery
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Application number
PCT/CN2023/087373
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English (en)
Chinese (zh)
Inventor
张水蓉
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北京车和家汽车科技有限公司
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Publication of WO2023198004A1 publication Critical patent/WO2023198004A1/fr

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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
    • H01M10/052—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
    • H01M10/056—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
    • H01M10/056—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
    • 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 disclosure relates to the technical field of electrochemical devices, and in particular, to a battery electrolyte and a lithium-ion battery containing the same.
  • lithium-ion batteries With the continuous popularity of electric vehicles, lithium-ion batteries have become one of the most widely used secondary batteries due to their advantages of high voltage, high energy density and long cycle life.
  • more stringent requirements have been put forward for the energy density and storage performance of lithium-ion batteries under cycling and high-temperature conditions.
  • silicon has the highest theoretical capacity (4200mAh/g); much higher than the 372mAh/g of graphite anode, the capacity of silicon-carbon anode materials mixed with silicon can reach 400-650mAh/g. level, therefore, in order to improve the energy density of lithium-ion batteries, more and more attention has been paid to the application of silicon.
  • the most ideal method at present is to use high-voltage ternary cathode materials with silicon anodes.
  • silicon due to the large volume expansion of silicon (up to 300% expansion), the silicon
  • SEI solid electrolyte interface
  • the electrolyte needs to be continuously consumed, eventually causing the electrolyte to dry up and the cycle to decay rapidly.
  • the interface between the cathode and the electrolyte is unstable.
  • the present disclosure provides a battery electrolyte and a lithium-ion battery containing the same.
  • Using the electrolyte provided by the present disclosure in a lithium-ion battery using a high-voltage ternary cathode material and a silicon system can significantly improve the cycle performance and reduce the reaction between the cathode and the electrolyte, thus reducing the occurrence of gas production and improving the performance of the battery. safety.
  • the present disclosure provides an electrolyte for batteries, the composition of which includes propylene carbonate, Fluoroethylene carbonate and lithium difluorophosphate, based on the total mass of the electrolyte being 100%, the content of the propylene carbonate is a%, the content of fluoroethylene carbonate is b%, and the lithium difluorophosphate The content is c%, and the a, b and c satisfy the following relationship: 0.1 ⁇ (b/a)/c ⁇ 10, and 3 ⁇ b ⁇ 13.
  • the electrolyte provided by the present disclosure includes three components: propylene carbonate (PC), fluoroethylene carbonate (FEC) and lithium difluorophosphate (LiPO 2 F 2 ).
  • PC propylene carbonate
  • FEC fluoroethylene carbonate
  • LiPO 2 F 2 lithium difluorophosphate
  • fluoroethylene carbonate can not only form an excellent SEI film on the surface of the silicon system negative electrode, but also quickly repair the newly exposed interface caused by silicon expansion and contraction, and at the same time suppress silicon expansion; at the same time,
  • the addition of lithium difluorophosphate can form a protective film on the positive electrode and improve high-temperature performance. Therefore, when the three are used together, the cycle capacity retention rate of the obtained lithium-ion battery cell can be better, and the problem of gas production during high-temperature storage can be eliminated. significantly improved.
  • the content of propylene carbonate is high, in order to avoid the disadvantage of poor compatibility with the negative electrode material, the content of fluorinated ethylene carbonate needs to be increased accordingly.
  • the content of fluorinated ethylene carbonate is increased, it will easily Decomposition produces hydrogen fluoride, which will damage the surface of the cathode, especially the high-voltage lithium-nickel composite oxide cathode, thus deteriorating high-temperature storage performance.
  • the addition of lithium difluorophosphate can improve high-temperature performance, when its content is increased, it will affect the negative electrode SEI film. Therefore, the addition amounts of PC, FEC and LiPO 4 F 2 need to be within the limited range of this disclosure. Able to achieve better application results.
  • (b/a)/c described in this disclosure can be 0.2, 0.5, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.7, 4, 4.2, 4.5, 4.8 ,5,6,7,8,9, etc.
  • 3 ⁇ b ⁇ 13, and b can be 3.2, 3.5, 3.8, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, etc.
  • 0.8 ⁇ (b/a)/c ⁇ 6 such as 0.9, 1.0, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4.0, 4.2, 4.5, 4.8, 5.0, 5.2, 5.5, 5.8, etc.
  • 7 ⁇ a ⁇ 25, and a in the present disclosure can be 8, 9, 10, 11, 12, 13 , 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, etc.
  • 0.1 ⁇ c ⁇ 1, and c in the present disclosure can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, etc.
  • the content of propylene carbonate is 7-25%
  • the content of fluorinated ethylene carbonate is 3-13%
  • the content of diethylene carbonate is 3-13%.
  • the content of lithium fluorophosphate is 0.1-1%, and 0.1 ⁇ (content of fluoroethylene carbonate/content of propylene carbonate)/content of lithium difluorophosphate ⁇ 10.
  • the electrolyte In the battery electrolyte, a conductive lithium salt should also be added. As a preferred technical solution of the present disclosure, the electrolyte also includes lithium hexafluorophosphate (LiPF 6 ).
  • the concentration of lithium hexafluorophosphate is 0.7-1.3mol/L, such as 0.8mol/L, 0.9mol/L, 1.0mol/L, 1.1mol/L , 1.2mol/L, etc.
  • the electrolyte solution also includes chain carbonate, and the chain carbonate
  • the preferred carbonate is ethyl methyl carbonate (EMC).
  • the content of the ethyl methyl carbonate is 20-65wt%, such as 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt%, 60wt%, etc.
  • the electrolyte solution also includes other non-aqueous solvents.
  • the non-aqueous solvent is selected from ethylene carbonate (EC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC) or ethyl carbonate. Any one or a combination of at least two of propyl esters (EPC).
  • the present disclosure provides a lithium-ion battery including the electrolyte described in the first aspect.
  • the lithium ion battery further includes a positive electrode and a negative electrode.
  • the positive electrode includes a positive electrode current collector and a positive electrode active material layer located on one side of the positive electrode.
  • the components of the positive electrode active material layer include a positive electrode active material and a conductive agent.
  • the positive electrode includes a positive active material, and the composition of the positive active material includes a lithium-nickel composite oxide, and the lithium-nickel composite oxide contains divalent nickel and trivalent nickel, The content ratio of the divalent nickel to trivalent nickel on the surface of the positive electrode active material is greater than the content ratio of the divalent nickel to trivalent nickel in the center of the positive electrode active material.
  • the lithium-nickel composite oxide described in the present disclosure is a high-voltage, high-nickel ternary cathode material.
  • cathode materials 6 series or 8 series such as NCM811, etc., can meet the limitations of the present disclosure and realize the present disclosure. purpose of invention.
  • the positive electrode active material surface mentioned in this disclosure refers to the outermost 50 nm area of the positive electrode active material particle toward the center direction as the surface.
  • the center of the positive active material in this disclosure refers to the center of the positive active material particle within a region of 50 nm from the center toward the surface.
  • the cathode active material In the cathode active material provided by the present disclosure, its metal elements not only include lithium and nickel, but also contain metal elements such as manganese and cobalt in the high-voltage ternary cathode material.
  • the sum of the nickel content is not less than 60%, such as 62%, 65%, 68%, 70%, 72%, 75%, 78%, etc.
  • the negative electrode includes a negative electrode current collector and a negative electrode active material layer located on one side of the negative electrode.
  • the negative electrode is composed of silicon material and graphite material.
  • the addition amount of the silicon material is 0-20%, excluding 0, such as 1%, 2%, 5%, 8%, 10%, 12%, 15%, 18%, etc.
  • the silicon material is SiO z , where 0.5 ⁇ z ⁇ 1.5.
  • the lithium ion battery includes a positive electrode, a negative electrode, a separator and the electrolyte described in the first aspect.
  • the electrolyte provided by the present disclosure can be used as the electrolyte, which can significantly improve the cycle performance of the lithium-ion battery, and its storage Produce
  • the gas properties can also be improved and are less likely to bulge, which can improve the safety of lithium-ion batteries.
  • the full charge voltage of the lithium-ion battery is ⁇ 4.25V.
  • electrolyte provided by the present disclosure in a lithium-ion battery using a high-voltage ternary cathode material and a silicon system can significantly improve cycle performance and reduce the reaction between the cathode and the electrolyte, thus reducing the occurrence of gas production. Improve battery safety;
  • the battery electrolyte and lithium-ion battery preparation method provided by the present disclosure are simple and easy to implement, and can be suitable for industrial production.
  • This embodiment provides a lithium-ion battery, and the preparation method is as follows:
  • LiNi 0.8 Co 0.1 Mn 0.1 NCM811
  • SP conductive carbon
  • CNTs carbon nanotubes
  • PVDF polyvinylidene fluoride
  • isolation film Use polyethylene film as the isolation film, stack the positive electrode, isolation film and negative electrode in order, so that the isolation film is between the positive and negative electrodes to play the role of isolation, then roll it, put it into the aluminum plastic film, and heat it at 80°C After drying, the electrolyte is injected, and through processes such as vacuum packaging, standing, formation, and shaping, a lithium-ion battery is obtained.
  • Cycle test Place the finished lithium-ion battery in a constant temperature box at 45°C for 30 minutes, charge it to 4.25V at a constant charging rate of 1.0C, then charge it at a constant voltage until the charging rate is 0.05C, let it stand for 5 minutes, and then Discharge to 3.0V at a constant discharge rate of 1.0C, recorded as the initial discharge capacity D 0 , and then perform a cycle test as follows:
  • step 1) Repeat step 1) to step 4) 1000 times to obtain capacity D 1 ;
  • Capacity retention rate (%) D 1 /D 0 ⁇ 100%
  • the finished lithium-ion battery is placed in a constant temperature box at 25°C for 30 minutes, charged to 4.25V at a constant charging rate of 1.0C, then charged at a constant voltage to a charging rate of 0.05C, left for 5 minutes, and the cell thickness is tested H 0 ;
  • High temperature expansion rate (%) (H 1 -H 0 )/H 0 ⁇ 100%
  • This comparative example provides a lithium ion battery.
  • Example 4 The difference from Example 4 is that in the electrolyte used in this comparative example, the added amount of fluoroethylene carbonate is 1% (Comparative Example 3) and 15% (Comparative Example 4).
  • This comparative example provides a lithium ion battery.
  • Example 4 The difference from Example 4 is that the composition of the electrolyte provided in this comparative example is shown in Table 2.
  • the amount of fluoroethylene carbonate needs to be in the range of 3-13wt%, and (b/a)/c needs to be in the range of 0.1-10.
  • the final lithium-ion battery has a better capacity retention rate and a lower high-temperature expansion rate.
  • This comparative example provides a lithium ion battery.
  • Example 4 The difference from Example 4 is that in the electrolyte used in this comparative example, propylene carbonate (PC) is replaced by carbon Vinyl acid ester (EC).
  • PC propylene carbonate
  • EC carbon Vinyl acid ester
  • This comparative example provides a lithium ion battery.
  • Example 4 The difference from Example 4 is that in the electrolyte used in this comparative example, fluoroethylene carbonate (FEC) is replaced by ethylene carbonate (EC)
  • Example 4 it can be seen from the comparison between Example 4 and Comparative Examples 7-8 that the present disclosure uses propylene carbonate, fluoroethylene carbonate and lithium difluorophosphate at the same time, and all three are indispensable.
  • This comparative example provides a lithium ion battery.
  • Example 4 The difference from Example 4 is that in this comparative example, the preparation method of the negative electrode is as follows:
  • Example 4 Comparative Example 9
  • the electrolyte provided by the present disclosure can significantly improve the capacity retention rate and high-temperature cycle performance of lithium-ion batteries when used in conjunction with high-voltage ternary cathode materials and negative electrodes containing silicon elements.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
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  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
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Abstract

La présente invention concerne un électrolyte de batterie et une batterie au lithium-ion le comprenant. Les composants de l'électrolyte comprennent du carbonate de propylène, du carbonate de fluoroéthylène et du difluorophosphate de lithium, la masse totale de l'électrolyte étant de 100 %, la teneur en carbonate de propylène étant de a %, la teneur en carbonate de fluoroéthylène étant de b %, et la teneur en difluorophosphate de lithium étant c %, a, b et c satisfaisant la relation suivante : 0,1 ≤ (b/a)/c ≤ 10, et 3 ≤ b ≤ 13.
PCT/CN2023/087373 2022-04-11 2023-04-10 Électrolyte de batterie et batterie au lithium-ion le comprenant WO2023198004A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202210375429.3 2022-04-11
CN202210375429 2022-04-11

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WO2023198004A1 true WO2023198004A1 (fr) 2023-10-19

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011187234A (ja) * 2010-03-05 2011-09-22 Mitsubishi Chemicals Corp 非水系電解液及びそれを用いた非水系電解液二次電池
CN112331914A (zh) * 2019-08-05 2021-02-05 杉杉新材料（衢州）有限公司 一种不含碳酸乙烯酯溶剂的锂离子电池非水电解液及电池
CN113036223A (zh) * 2021-05-28 2021-06-25 天能电池集团股份有限公司 一种超低温锂离子电池电解液
CN113410511A (zh) * 2021-06-29 2021-09-17 珠海冠宇电池股份有限公司 一种锂离子电池及电子装置
CN113422111A (zh) * 2021-06-23 2021-09-21 吉安谊盛电子材料有限公司 一种电解液及含有该电解液的锂离子电池

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011187234A (ja) * 2010-03-05 2011-09-22 Mitsubishi Chemicals Corp 非水系電解液及びそれを用いた非水系電解液二次電池
CN112331914A (zh) * 2019-08-05 2021-02-05 杉杉新材料（衢州）有限公司 一种不含碳酸乙烯酯溶剂的锂离子电池非水电解液及电池
CN113036223A (zh) * 2021-05-28 2021-06-25 天能电池集团股份有限公司 一种超低温锂离子电池电解液
CN113422111A (zh) * 2021-06-23 2021-09-21 吉安谊盛电子材料有限公司 一种电解液及含有该电解液的锂离子电池
CN113410511A (zh) * 2021-06-29 2021-09-17 珠海冠宇电池股份有限公司 一种锂离子电池及电子装置

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