Interface modifier of solid electrolyte and solid lithium ion battery
By using an interface modifier composed of lithium salt and solvent in solid-state lithium-ion batteries to combine with sulfide electrolytes, the problem of increased battery interface impedance and poor stability in solid-state lithium-ion batteries is solved, and the cycle stability and electricity of the battery are improved Chemical properties.
Patent Information
- Application Number
- CN202310683075.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-09
- Publication Date
- 2024-12-10
AI Technical Summary
In solid-state lithium-ion batteries, the battery interface impedance caused by solid-solid contact increases, affecting cycle stability, and the interface instability between the sulfide solid electrolyte and the electrode affects battery performance.
An interface modifier including lithium salt and solvent is adopted. The lithium salt is selected from LiBOB, LiDFOB and LiDODFP, the solvent is selected from acrylic carbonate, methacrylate, etc., combined with sulfur silver germanium ore, Thio-LISICON and LGPS type The sulfide electrolyte forms a stable positive electrode side interface modifier, used between the positive electrode and the electrolyte of a solid lithium-ion battery.
It improves lithium ion conductivity and oxidative stability, enhances the mechanical flexibility and chemical stability of the battery, improves the cyclic stability and electrochemical performance of the battery, and reduces the interface impedance.
Smart Images
Figure CN119108611A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to, but is not limited to, energy storage battery technology, and in particular to, but is not limited to, an interface modifier for a solid electrolyte and a solid-state lithium-ion battery. Background Art
[0002] Lithium-ion batteries are a highly efficient energy storage technology. Their high specific energy, high efficiency, and environmental friendliness make them widely used in electronic products, electric vehicles, and other fields. However, traditional liquid lithium-ion batteries have electrolyte volatilization and leakage during the charging and discharging process, which seriously affects the service life of lithium-ion batteries. At the same time, organic electrolytes have some safety hazards, which affect the long-term development of lithium-ion batteries.
[0003] All-solid-state batteries use solid electrolytes to replace liquid electrolytes, which can solve the safety problems of liquid batteries and improve the energy density of batteries, ushering in a turning point for the development of lithium-ion batteries. Solid electrolytes are the key to solid-state batteries, affecting the energy density, cycle stability and safety of solid-state lithium-ion batteries. Solid electrolytes are composed of two types: polymer solid electrolytes and inorganic solid electrolytes. Inorganic solid electrolytes include solid electrolyte types such as oxides, sulfides, borides and halides. Among them, sulfide solid electrolytes have the characteristics of high ionic conductivity, good mechanical properties, wide electrochemical window, and environmental friendliness, thus achieving excellent stability. Sulfide solid electrolytes have good compatibility with positive electrode materials such as lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium manganese oxide, and lithium iron phosphate. Therefore, sulfide solid electrolytes have become the most promising electrolytes in solid-state batteries. Thioargyrodite solid electrolytes have high ionic conductivity, setting off a new wave of research and development.
[0004] In addition to the same alkali metal salt as in CN105374980A, the interface wetting additive in CN105374980B also adds other compounds that can be combined with alkali metal salts to form a molten salt electrolyte. The lithium salt structure described in the patent is different from that of LiBOB. The above-mentioned alkali metal salt does not have the ability to conduct lithium ions. The lithium salt used in this application, such as LiBOB, is a commonly used lithium salt and has a higher ionic conductivity. Summary of the invention
[0005] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.
[0006] Although sulfide solid electrolytes have high lithium ion conductivity, excellent mechanical ductility and simple preparation process, the solid-solid contact between the solid-state battery electrode and the electrolyte increases the interfacial impedance of the battery. The change in the volume of the positive and negative electrodes during the charge and discharge process affects the stability of the battery interface, which in turn affects the cycle stability of the battery. There is an urgent need for a transition layer with high oxidation stability, high lithium ion conductivity, good flexibility and stability with sulfide electrolyte materials. The present application provides a positive electrode side interface modifier that has both positive active materials and sulfide electrolyte stability to solve the current situation of poor performance of sulfide solid-state batteries.
[0007] The present application provides an interface modifier for a solid electrolyte, the interface modifier comprising a lithium salt and a solvent, the lithium salt being selected from any one or more of lithium dioxalatoborate (LiBOB), lithium difluorooxalatoborate (LiDFOB) and lithium difluorodioxalatophosphate (LiDODFP);
[0008] The solvent is selected from any one or more of propylene carbonate (PC), methacrylate, acrylate, and vinyl ethylene carbonate (VEC);
[0009] The solid electrolyte is selected from any one or more of Argyrodite sulfide solid electrolytes, Thio-LISICON electrolytes and LGPS sulfide electrolytes.
[0010] In some embodiments provided in the present application, the acrylic acid ester is selected from any one or more of acrylic acid lower alkanol esters.
[0011] In some embodiments provided herein, the acrylate is selected from any one or more of methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate and tert-butyl acrylate.
[0012] In some embodiments provided herein, the methacrylate is selected from any one or more of methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate and tert-butyl methacrylate.
[0013] In some embodiments provided herein, the solid electrolyte is selected from Li6PS5X (X = Cl, Br, I), Li 4.275 Ge 0.61 Ga 0.25 S4 solid electrolyte and Li 10 GeP2S 12 Any one or more of solid electrolytes.
[0014] In some embodiments provided herein, the concentration of the lithium salt in the interfacial modifier is 0.1M to 4M.
[0015] On the other hand, the present application provides a solid-state lithium-ion battery, which includes the above-mentioned interface modifier.
[0016] In some embodiments provided herein, the interfacial modifier is located between the positive electrode of the solid-state lithium-ion battery and the solid-state electrolyte.
[0017] In some embodiments provided in this application, the amount of the interface modifier is 0.1 mL / cm 2 To 0.3mL / cm 2 .
[0018] In some embodiments provided in the present application, the positive electrode of the solid-state lithium-ion battery includes a ternary positive electrode material.
[0019] In some embodiments provided in the present application, during the preparation of a solid-state lithium-ion battery, the solvent addition and subsequent assembly process takes 1 to 2 minutes, a small amount of solvent volatilization is negligible, and no chemical reaction occurs.
[0020] On the other hand, the present application provides a device, which includes a device housing, and a motor and / or a circuit board located inside the device housing, and the device housing also includes a battery, which is electrically connected to the motor and / or the circuit board for powering the motor and / or the circuit board, and the battery includes the above-mentioned solid-state lithium-ion battery.
[0021] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be invented and obtained by the schemes described in the description. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.
[0023] Figure 1 Impedance diagrams of different interface modifiers in the examples and comparative examples of the present application.
[0024] Figure 2 This is the voltage-current curve of the battery assembled based on Li6PS5Cl electrolyte in the application example of this application.
[0025] Figure 3This is the voltage-current curve of the battery assembled based on Li6PS5Br electrolyte in the application example of this application.
[0026] Figure 4 This is the voltage-current curve of the battery assembled based on Li6PS5I electrolyte in the application example of this application.
[0027] Figure 5 This is the voltage-current curve of a battery assembled based on Li4.275Ge0.61Ga0.25S4 (LGGS) electrolyte in the application example of this application.
[0028] Figure 6 In this application example, based on Li 10 GeP2S 12 Voltage-current curves of the battery assembled with (LGPS) electrolyte. DETAILED DESCRIPTION
[0029] In order to make the purpose, technical solution and advantages of the present application more clear, the embodiments of the present application are described in detail below. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.
[0030] In an embodiment of the present application, an interface modifier for a solid electrolyte is provided, wherein the interface modifier comprises a lithium salt and a solvent, wherein the lithium salt is selected from any one or more of lithium dioxalatoborate, lithium difluorooxalatoborate and lithium difluorodioxalatophosphate;
[0031] The solvent is selected from any one or more of propylene carbonate, methacrylate, acrylate, and vinyl ethylene carbonate;
[0032] The solid electrolyte is selected from any one or more of argyrodite sulfide solid electrolytes, sulfur-based ultrafast ion conductor electrolytes and LGPS sulfide electrolytes.
[0033] Exemplarily, the solid electrolyte is selected from Li6PS5X (X = Cl, Br, I) solid electrolyte, Li 4.275 Ge 0.61 Ga 0.25 S4 solid electrolyte and Li 10 GeP2S 12 Any one or more of solid electrolytes.
[0034] Illustratively, the concentration of the lithium salt in the interface modifier is 0.1M to 4M.
[0035] Exemplarily, the acrylic acid ester is selected from any one or more of acrylic acid lower alkyl esters.
[0036] Illustratively, the acrylic acid ester is selected from any one or more of methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate and tert-butyl acrylate.
[0037] Exemplarily, the methacrylate is selected from any one or more of methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate and tert-butyl methacrylate.
[0038] In another aspect, an embodiment of the present application further provides a solid-state lithium-ion battery, wherein the solid-state lithium-ion battery comprises the above-mentioned interface modifier.
[0039] Exemplarily, the interfacial modifier is located between the positive electrode of the solid-state lithium-ion battery and the solid-state electrolyte.
[0040] For example, the amount of the interfacial modifier is 0.1 mL / cm 2 To 0.3mL / cm 2 .
[0041] Exemplarily, the positive electrode of the solid-state lithium-ion battery includes a ternary positive electrode material.
[0042] Exemplarily, the structural formula of the ternary cathode material is Li a Ni x Co y M z O2, M is selected from at least one of Mn, Al, Zr, Ti, V, Mg, Fe, Mo, and B, 0.95≤a≤1.2, x>0, y>0, z>0, and x+y+z=1; for example, the ternary positive electrode material may be NCM532, NCM622, NCM811, etc.
[0043] On the other hand, an embodiment of the present application also provides a device, which includes a device housing, and a motor and / or a circuit board located inside the device housing, and the device housing also includes a battery, which is electrically connected to the motor and / or the circuit board for powering the motor and / or the circuit board, and the battery includes the above-mentioned solid-state lithium-ion battery.
[0044] Example 1
[0045] Prepare a propylene carbonate solution of lithium bis(oxalatoborate) (LiBOB), weigh LiBOB in a glove box filled with argon (water < 0.01 ppm, oxygen < 0.01 ppm), then add propylene carbonate thereto, stir magnetically for 2 to 3 hours, and obtain an interface modifier after the lithium salt is completely dissolved. Use an ion conductivity tester to measure the ionic conductivity of the interface modifier.
[0046] Table 1 Conductivity of the interface modifier when the lithium salt is LiBOB and the solvent is propylene carbonate
[0047]
[0048]
[0049] Example 2
[0050] Prepare a solution of lithium bis(oxalatoborate) (LiBOB) in ethylene carbonate, weigh LiBOB in a glove box filled with argon (water <0.01, oxygen <0.01), then add ethylene carbonate thereto, stir magnetically for 2 to 3 hours, and obtain an interfacial modifier after the lithium salt is completely dissolved. Use an ion conductivity tester to measure the ionic conductivity of the interfacial modifier.
[0051] Table 2 Conductivity of the interface modifier when the lithium salt is LiBOB and the solvent is ethylene carbonate
[0052] Lithium salt concentration Solvents Conductivity (mS / cm) 0.2M LiBOB Ethylene carbonate 1.526 1M LiBOB Ethylene carbonate 1.0212 2M LiBOB Ethylene carbonate 0.765 3M LiBOB Ethylene carbonate 0.0953
[0053] Example 3
[0054] Prepare an acrylate solution of lithium borate oxalate (LiBOB), weigh LiBOB in a glove box filled with argon (water < 0.01 ppm, oxygen < 0.01 ppm), then add acrylate thereto, stir magnetically for 2 to 3 hours, and obtain an interface modifier after the lithium salt is completely dissolved. Use an ion conductivity tester to measure the ionic conductivity of the interface modifier.
[0055] The acrylic acid ester in this embodiment is methyl acrylate, purchased from MacLean Company, CAS No.: 96-33-3; the effects of using other acrylic acid esters and methacrylic acid esters in the interface modifier are close to the effects of methyl acrylate in this embodiment.
[0056] Table 3 Conductivity of interface modifiers with lithium salt being LiBOB and solvent being acrylate
[0057] Lithium salt concentration Solvents Conductivity (mS / cm) 0.2M LiBOB Acrylate 1.354 1M LiBOB Acrylate 0.817 2M LiBOB Acrylate 0.683 3M LiBOB Acrylate 0.0524
[0058] Comparative Example 1
[0059] Prepare a polyethylene glycol dimethacrylate solution of lithium bis(oxalatoborate) (LiBOB), weigh LiBOB in a weighing bottle in a glove box filled with argon (water <0.01ppm, oxygen <0.01ppm), then add polyethylene glycol dimethacrylate thereto, stir magnetically for 2 to 3 hours, and obtain an interfacial modifier after the lithium salt is completely dissolved. Use an ion conductivity tester to measure the ionic conductivity of the interfacial modifier.
[0060] In this comparative example, polyethylene glycol dimethacrylate was purchased from Maclean Company, CAS No.: 25852-47-5.
[0061] Comparative Example 2
[0062] Prepare a m-xylene solution of lithium bis(oxalatoborate) (LiBOB), weigh LiBOB in a glove box filled with argon (water < 0.01 ppm, oxygen < 0.01 ppm), then add m-xylene, stir magnetically for 2 to 3 hours, and obtain an interface modifier after the lithium salt is completely dissolved. Use an ion conductivity tester to measure the ionic conductivity of the interface modifier.
[0063] Comparative Example 3
[0064] Prepare a 1,3-dioxolane solution of lithium borate oxalate (LiBOB), weigh LiBOB in a glove box filled with argon (water < 0.01 ppm, oxygen < 0.01 ppm), then add 1,3-dioxolane thereto, stir magnetically for 2 to 3 hours, and obtain an interfacial modifier after the lithium salt is completely dissolved. Use an ion conductivity tester to measure the ionic conductivity of the interfacial modifier.
[0065] Comparative Example 4
[0066] Prepare a dibromomethane solution of lithium bis(oxalatoborate) (LiBOB), weigh LiBOB in a glove box filled with argon (water < 0.01 ppm, oxygen < 0.01 ppm), then add dibromomethane, stir magnetically for 2 to 3 hours, and obtain an interface modifier after the lithium salt is completely dissolved. Use an ion conductivity tester to measure the ionic conductivity of the interface modifier.
[0067] Comparative Example 5
[0068] Prepare a vinyl carbonate solution of lithium bis(oxalatoborate) (LiBOB), weigh LiBOB in a weighing bottle in a glove box filled with argon (water < 0.01 ppm, oxygen < 0.01 ppm), then add vinyl carbonate thereto, stir magnetically for 2 to 3 hours, and obtain an interfacial modifier after the lithium salt is completely dissolved. Use an ion conductivity tester to measure the ionic conductivity of the interfacial modifier.
[0069] Comparative Example 6
[0070] Prepare a methyl methacrylate solution of lithium bis(oxalatoborate) (LiBOB), weigh LiBOB in a glove box filled with argon (water < 0.01 ppm, oxygen < 0.01 ppm), then add methyl methacrylate thereto, stir magnetically for 2 to 3 hours, and obtain an interface modifier after the lithium salt is completely dissolved. Use an ion conductivity tester to measure the ionic conductivity of the interface modifier.
[0071] Comparative Example 7
[0072] Prepare a solution of lithium borate oxalate (LiBOB) in vinyl sulfite, weigh LiBOB in a glove box filled with argon (water < 0.01 ppm, oxygen < 0.01 ppm), then add vinyl sulfite thereto, stir magnetically for 2 to 3 hours, and obtain an interface modifier after the lithium salt is completely dissolved. Use an ion conductivity tester to measure the ionic conductivity of the interface modifier.
[0073] Comparative Example 8
[0074] Prepare a vinyl acetate solution of lithium borate bis(oxalate) (LiBOB), weigh LiBOB in a glove box filled with argon (water < 0.01 ppm, oxygen < 0.01 ppm), then add vinyl acetate, stir magnetically for 2 to 3 hours, and obtain an interface modifier after the lithium salt is completely dissolved. Use an ion conductivity tester to measure the ionic conductivity of the interface modifier.
[0075] Comparative Example 9
[0076] Prepare a cyanoacrylate solution of lithium borate bis(oxalate) (LiBOB), weigh LiBOB in a glove box filled with argon (water <0.01ppm, oxygen <0.01ppm), then add cyanoacrylate to it, stir magnetically for 2h to 3h, and obtain an interface modifier after the lithium salt is completely dissolved. Use an ion conductivity tester to measure the ion conductivity of the interface modifier.
[0077] Comparative Example 10
[0078] Prepare a solution of lithium bis(oxalatoborate) (LiBOB) in ethylene carbonate, weigh LiBOB in a glove box filled with argon (water <0.01, oxygen <0.01), then add ethylene carbonate, stir magnetically for 2 to 3 hours, and obtain an interface modifier after the lithium salt is completely dissolved. Use an ion conductivity tester to measure the ionic conductivity of the interface modifier.
[0079] Table 4 Electrical conductivity of interface modifiers of Examples and Comparative Examples
[0080]
[0081]
[0082] Application Examples
[0083] Thio-LISICON type sulfide electrolyte, LGPS type sulfide electrolyte, and argyrodite type sulfide electrolyte were assembled into mold batteries with positive electrode (NCM811) and negative electrode material (Si negative electrode or metal Li) respectively. During the assembly process, 0.2 mL / cm 2 The interfacial modifiers are used to measure the electrochemical performance of the battery.
[0084] Table 5 Effect of the same interface modifier on the electrochemical performance of lithium symmetric batteries assembled with different solid sulfide electrolytes
[0085]
[0086] In Table 5, the Argyrodite sulfide solid electrolytes are Li6PS5Cl, Li6PS5Br, and Li6PS5I; the LGPS sulfide electrolyte is Li 10 GeP2S 12 ; The Thio-LISICON electrolyte is Li 4.275 Ge 0.61 Ga 0.25 S4.
[0087] The critical current density refers to the maximum current density that a battery can withstand when it fails. The interface modifier described in this application can achieve a current of 0.75 mA (electrode area 0.785 cm 2 , so the critical current density is 0.96mA / cm 2 ); while the critical current of LGPS and LGGS sulfide electrolytes is 0.5 mA (critical current density is 0.64 mA / cm 2 ). In comparison, the interface modifier described in the present application enables the argyrodite-type sulfide electrolyte to have good electrochemical stability. The S bond and P bond energy of the argyrodite-type sulfide solid electrolyte are relatively weak, providing a good lithium ion transmission channel.
[0088] The lithium ion conductivity of the interface modifier prepared in the present application can reach up to 6.55 mS / cm, has better lithium ion exchange capacity, and can accelerate the reaction rate.
[0089] The above-mentioned solid electrolyte was combined with the interface modifier provided in the present application. After 30 days of storage, the supernatant of the mixed solution remained transparent and colorless, and no obvious color change was found, indicating that the solid electrolyte, especially the argyrodite electrolyte, and the interface modifier provided in the present application have excellent chemical stability.
Claims
1. An interface modifier for a solid electrolyte, characterized in that: The interface modifier comprises a lithium salt and a solvent, wherein the lithium salt is selected from any one or more of lithium dioxalatoborate, lithium difluorooxalatoborate and lithium difluorooxalatophosphate; The solvent is selected from any one or more of propylene carbonate, methacrylate, acrylate, and vinyl ethylene carbonate; The solid electrolyte is selected from any one or more of argyrodite sulfide solid electrolytes, sulfur-based ultrafast ion conductor electrolytes and LGPS sulfide electrolytes.
2. The interface modifier according to claim 1, characterized in that The solid electrolyte is selected from Li6PS5X (X = Cl, Br, I) solid electrolyte, Li 4.275 Ge 0.61 Ga 0.25 S4 solid electrolyte and Li 10 GeP2S 12 Any one or more of solid electrolytes.
3. The interface modifier according to claim 1 or 2, characterized in that: The concentration of the lithium salt in the interface modifier is 0.1M to 4M.
4. The interface modifier according to claim 1 or 2, characterized in that: The acrylic acid ester is selected from any one or more of acrylic acid lower alkanol esters; Optionally, the acrylic acid ester is selected from any one or more of methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate and tert-butyl acrylate.
5. The interface modifier according to claim 1 or 2, characterized in that: The methacrylate is selected from any one or more of methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate and tert-butyl methacrylate.
6. A solid-state lithium-ion battery, characterized in that: The solid-state lithium-ion battery comprises the interface modifier according to any one of claims 1 to 5.
7. The solid-state lithium-ion battery according to claim 6, characterized in that: The interface modifier is located between the positive electrode of the solid-state lithium-ion battery and the solid-state electrolyte.
8. The solid-state lithium-ion battery according to claim 6 or 7, characterized in that: The amount of the interface modifier is 0.1 mL / cm 2 To 0.3mL / cm 2 .
9. The solid-state lithium-ion battery according to claim 6 or 7, characterized in that: The positive electrode of the solid-state lithium-ion battery includes a ternary positive electrode material.
10. A device, characterized in that: The device includes a device housing, and a motor and / or a circuit board located inside the device housing. The device housing also includes a battery, which is electrically connected to the motor and / or the circuit board for powering the motor and / or the circuit board. The battery includes the solid-state lithium-ion battery described in any one of claims 6 to 9.