A halide / sulfide solid electrolyte material and preparation method and solid-state battery

Abstract

The present invention proposes a halide / sulfide solid electrolyte material, a preparation method, and a solid-state battery, which belongs to the field of solid-state battery technology and can solve the problems that existing halide solid electrolytes are sensitive to humidity and temperature and have complex preparation processes, and sulfide electrolytes are not suitable for large-scale commercial applications due to high cost, poor interfacial stability, and sensitivity to air. The halide / sulfide solid electrolyte material includes halide / sulfide solid electrolyte powder and a binder, and the mass ratio of halide / sulfide solid electrolyte powder to binder is 1:(10~100). The present invention can be applied to the preparation of solid-state batteries. The introduced polymer-based binder is conducive to enhancing the compatibility of halide / sulfide solid electrolytes and electrode sheets, reducing interfacial impedance, improving ionic conductivity, and further improving the energy density and cycle stability of solid-state batteries.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid-state batteries, and in particular relates to a halide / sulfide solid electrolyte material and a preparation method thereof, and a solid-state battery. Background Art

[0002] In the field of energy material technology, solid-state batteries have been widely used due to their high safety and high specific energy characteristics. Solid-state electrolytes are the key variables of solid-state batteries. As the core of all-solid-state batteries, solid-state electrolytes determine the kinetics of ion transport and the interfacial compatibility with the positive and negative electrodes. Among the many solid-state electrolytes, halide electrolytes and sulfide electrolytes have attracted much attention due to their unique advantages. Among them, sulfide electrolytes have high ionic conductivity and excellent mechanical properties, but due to high cost, poor interfacial stability, and sensitivity to air, the large-scale commercial application of sulfide solid electrolytes is restricted; compared with existing sulfide solid electrolytes, halide electrolytes have higher chemical stability and a wider electrochemical stability window, but halide solid electrolytes are sensitive to humidity and temperature, and the preparation process is complex.

[0003] Moreover, the current production of sulfide or halide solid electrolytes usually involves processes such as crushing, coating, mixing, and bonding. The process route is complex, energy-intensive, and not conducive to continuous production. In order to reduce interfacial impedance, sulfide or halide solid electrolyte powders are usually coated with positive electrode materials. However, the coating process is often just physical adsorption without any mutual chemical reaction. During the battery cycle, it is very easy to cause the coating layer to fall off and poor contact between the particles inside the positive electrode, hindering the transmission of lithium ions, increasing the internal resistance of the battery, and ultimately leading to rapid decay of the battery capacity.

[0004] Therefore, it is necessary to provide a halide / sulfide solid electrolyte material with a simple preparation process and suitable for continuous production and to apply it to solid-state batteries to enhance the compatibility between the electrode and the solid electrolyte, reduce the interfacial impedance, and improve the ionic conductivity. Summary of the Invention

[0005] The present invention addresses the technical problems that existing halide solid electrolytes are sensitive to humidity and temperature and have complex preparation processes, and sulfide electrolytes are not suitable for large-scale commercial applications due to their high cost, poor interface stability, and sensitivity to air. A halide / sulfide solid electrolyte material, a preparation method, and a solid-state battery are proposed. These materials have the advantages of a simple preparation process and are suitable for continuous production. They can enhance the compatibility between electrodes and solid electrolytes, reduce interface impedance, improve ionic conductivity, and further improve the energy density and cycle stability of solid-state batteries.

[0006] To achieve the above objectives, the present invention employs a technical solution comprising a halide / sulfide solid electrolyte material comprising halide / sulfide solid electrolyte powder and a binder, wherein the mass ratio of halide / sulfide solid electrolyte powder to binder is 1:(10-100). By limiting this mass ratio, the present invention has the beneficial effect of enhancing the compatibility of the halide / sulfide solid electrolyte and the electrode sheet.

[0007] In one embodiment, the halide solid electrolyte powder includes Li a MX6、Li b TMX4 or Li 3-c M 1-c M c Any one or more of X6, wherein M is any one or more of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, In, Zr, Hf, TM is any one or more of Co, Zn, Al, Cr, Mg, Ni, X is any one or more of F, Cl, Br, I, 2≤a≤3, 0 <b≤2,0<c<1;

[0008] Sulfide solid electrolyte powder including Li 3.25 Ge 0.25 P 0.75 S4, Li 10 GeP2S 12 、Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Or any one or more of Li6PS5X, X is any one or more of Cl, Br, and I.

[0009] In one embodiment, the binder includes a cross-linking agent, a monomer, an electrolyte, and an initiator, and the mass ratio of the cross-linking agent, monomer, electrolyte, and initiator in the binder is 1:(15-30):(45-70):(0.016-0.31). By limiting the above mass ratio, the present invention obtains a binder with good interfacial wettability. Its viscoelasticity and flexibility are beneficial for enhancing the compatibility of the halide / sulfide solid electrolyte and the electrode sheet, reducing interfacial impedance, improving ionic conductivity, and further improving the energy density and cycle stability of the solid-state battery.

[0010] In one embodiment, the monomer includes any one or more of methyl acrylate, methyl methacrylate, acrylonitrile, trifluoroethyl acrylate, trifluoroethyl methacrylate, isocyanoethyl methacrylate, vinyl ethylene carbonate, and hexafluorobutyl acrylate.

[0011] In one embodiment, the crosslinking agent includes any one or more of pentaerythritol acrylate, trimethylolpropane triacrylate, triallyl phosphate, polyethylene glycol dimethacrylate, poly(ethylene glycol) diacrylate, octavinyl POSS, tetra(dimethylvinylsiloxy)silane, polyethylene glycol methyl ether methacrylate, polyethylene glycol methyl ether acrylate, and polyethylene glycol dimethacrylate.

[0012] In one embodiment, the electrolyte includes a lithium salt, an organic solvent and a functional additive, wherein the lithium salt concentration is 1.2 to 1.5 M, the lithium salt includes at least one of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium dioxalatoborate, lithium difluorooxalatoborate and lithium tetrafluoroborate; the organic solvent includes any one or more of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethyl monofluoroacetate, ethyl difluoroacetate, ethyl trifluoroacetate, ethyl 3-fluoropropionate, ethyl 3,3-difluoropropionate, ethyl 3,3,3-trifluoropropionate, ethyl 4,4,4-trifluorobutyrate and ethyl trifluoroacetoacetate; the functional additive includes 1,3-propylene sultone, vinylene carbonate, 1,1,2,2-tetrafluoroethyl-2,2,3 , any one or more of 3-tetrafluoropropyl ether, sodium difluorooxalatoborate, sodium difluorooxalatophosphate, vinyl sulfate, vinyl ethylene carbonate, ethylene sulfite, 1,4-butane sultone, fluoroethylene carbonate, bisfluoroethylene carbonate, ethylene glycol bispropionitrile ether, tris(trimethylsilyl)phosphate, and tris(trimethylsilyl)borate.

[0013] In one embodiment, the initiator includes any one of azobisisobutyronitrile, benzoyl peroxide, and 2,4-dichlorobenzoyl peroxide.

[0014] Another aspect of the present invention provides a method for preparing a halide / sulfide solid electrolyte material, comprising the following steps: mixing halide / sulfide solid electrolyte powder and a binder and then performing ultrasonic dispersion.

[0015] Another aspect of the present invention provides a solid-state battery prepared using any of the above-mentioned halide / sulfide solid electrolyte materials.

[0016] In one embodiment, a method for preparing a solid-state battery includes the following steps:

[0017] The halide / sulfide solid electrolyte powder and the binder are mixed and then ultrasonically dispersed to form a uniform mixed solution;

[0018] The positive electrode sheet, separator, and negative electrode sheet are assembled in sequence, and then the mixed solution is injected, followed by pressurization and heat treatment to obtain a solid-state battery. The pressurization pressure is 6.5-8.9 MPa, the pressurization time is 30-120 seconds, and the heat treatment temperature is 50-60°C, and the heat treatment time is 12-48 hours. By limiting the pressurization and heat treatment conditions, the present invention has the beneficial effects of increasing wettability and reducing impedance.

[0019] Compared with the prior art, the advantages and positive effects of the present invention are:

[0020] (1) The halide / sulfide solid electrolyte material provided by the present invention introduces a polymer-based binder. The polymer material has good interface wettability. The viscoelasticity and flexibility of the polymer material are conducive to enhancing the compatibility of the halide / sulfide solid electrolyte and the electrode sheet, reducing the interface impedance, improving the ionic conductivity, and further improving the energy density and cycle stability of the solid-state battery.

[0021] (2) The preparation method of the halide / sulfide solid electrolyte material provided by the present invention adopts ultrasonic mixing to introduce a polymer-based binder into the process of preparing the halide / sulfide solid electrolyte material, which can make the mixing more uniform. By introducing the polymer-based material as a binder, the halide / sulfide solid electrolyte material is fixed between the positive and negative electrodes, which improves the complex process and high-voltage requirements in the traditional pressing process, can significantly improve the ionic conductivity and interface stability of the material, and is conducive to reducing manufacturing costs and realizing large-scale production.

[0022] (3) The solid-state battery provided by the present invention is prepared using halide / sulfide solid electrolyte materials. When sulfide or halide solid electrolytes are used in solid-state batteries, they are in point-to-point contact with the positive and negative electrode materials. During the battery cycle, they will hinder the transmission of lithium ions and increase the internal resistance of the battery. After the introduction of polymer-based binders, the contact mode with the positive and negative electrode materials is transformed into face-to-face, which is beneficial to improving ionic conductivity and compatibility with positive and negative electrode materials, reducing interface impedance, and further improving the energy density and cycle stability of solid-state batteries.

[0023] (4) The present invention provides a method for preparing a solid-state battery. After the halide / sulfide solid electrolyte material is assembled with the positive and negative electrode materials and the separator into a battery, the heat treatment temperature does not exceed 60°C, thereby avoiding excessive energy loss and being suitable for continuous large-scale production. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] The embodiments of the present invention provide a halide / sulfide solid electrolyte material, a preparation method thereof, and a solid-state battery. By fixing the halide / sulfide solid electrolyte powder between the positive / negative electrode materials and the separator through a binder, and then pressurizing and heat-treating the battery, the solid-state battery can be obtained. By introducing a polymer-based material as the binder to fix the halide / sulfide solid electrolyte material between the positive and negative electrodes, the complex processes and high-pressure requirements in the traditional lamination process are improved, which is beneficial to enhancing the compatibility between the electrode and the solid electrolyte, can significantly improve the ionic conductivity and interface stability of the material, and further improve the energy density and cycle stability of the solid-state battery; the preparation method has simple process operation, mild reaction conditions, and less energy loss, which is beneficial to reducing the manufacturing cost and realizing large-scale production.

[0026] The present invention provides a solid electrolyte, which includes a halide / sulfide solid electrolyte powder and a binder, and the mass ratio of the halide / sulfide solid electrolyte powder to the binder is 1:(10 - 100). The binder includes a crosslinking agent, a monomer, an electrolyte, and an initiator, and the mass ratio of the crosslinking agent, the monomer, the electrolyte, and the initiator in the binder is 1:(15 - 30):(45 - 70):(0.016 - 0.31).

[0027] The halide solid electrolyte powder of the present invention includes any one or more of Li a MX6, Li b TMX4 or Li 3-c M 1-c M c X6, where M is any one or more of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, In, Zr, Hf, TM is any one or more of Co, Zn, Al, Cr, Mg, Ni, X is any one or more of F, Cl, Br, I, 2 ≤ a ≤ 3, 0 < b < 2, 0 < c < 1; the sulfide solid electrolyte powder includes Li 3.25 Ge 0.25 P 0.75 S4, Li 10 GeP2S 12 、Li 9.54 Si 1.74 P 1.44 S 11.7 Cl0.3 Or any one or more of Li6PS5X, X is any one or more of Cl, Br, and I.

[0028] The crosslinking agent in the adhesive of the present invention includes any one or more of pentaerythritol acrylate, trimethylolpropane triacrylate, triallyl phosphate, polyethylene glycol dimethacrylate, poly(ethylene glycol) diacrylate, octavinyl POSS, tetra(dimethylvinylsiloxy)silane, polyethylene glycol methyl ether methacrylate, polyethylene glycol methyl ether acrylate, and polyethylene glycol dimethacrylate; the monomer in the adhesive of the present invention includes any one or more of methyl acrylate, methyl methacrylate, acrylonitrile, trifluoroethyl acrylate, trifluoroethyl methacrylate, isocyanoethyl methacrylate, vinyl ethylene carbonate, and hexafluorobutyl acrylate; the initiator in the adhesive of the present invention includes one of azobisisobutyronitrile, benzoyl peroxide, and 2,4-dichlorobenzoyl peroxide; the electrolyte in the adhesive of the present invention includes a lithium salt, an organic solvent, and a functional additive, wherein the lithium salt concentration is 1.2 to 1.5 M, the lithium salt includes at least one of lithium hexafluorophosphate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium dioxalatoborate, lithium difluorooxalatoborate, and lithium tetrafluoroborate; the organic solvent includes any one or more of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethyl monofluoroacetate, ethyl difluoroacetate, ethyl trifluoroacetate, ethyl 3-fluoropropionate, ethyl 3,3-difluoropropionate, ethyl 3,3,3-trifluoropropionate, ethyl 4,4,4-trifluorobutyrate, and ethyl trifluoroacetoacetate; the functional additive includes 1,3-propylene sultone, vinylene carbonate, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, sodium difluorooxalatoborate, sodium difluorooxalatophosphate, vinyl sulfate, vinyl ethylene carbonate, ethylene sulfite, 1 , any one or more of 4-butane sultone, fluoroethylene carbonate, bisfluoroethylene carbonate, ethylene glycol bispropionitrile ether, tris(trimethylsilyl)phosphate, and tris(trimethylsilyl)borate.

[0029] The present invention provides a preparation method of a halide / sulfide solid electrolyte material, comprising the following steps: mixing halide / sulfide solid electrolyte powder and a binder and then performing ultrasonic dispersion.

[0030] Another aspect of the present invention provides a solid-state battery prepared using the above-mentioned halide / sulfide solid electrolyte material.

[0031] The method for preparing the solid-state battery of the present invention comprises the following steps:

[0032] Preparation of halide / sulfide solid electrolyte material: mixing halide / sulfide solid electrolyte powder and a binder and then ultrasonically dispersing them to form a uniform mixed solution;

[0033] Preparation of solid-state batteries: Assemble the positive electrode sheet, separator, and negative electrode sheet in sequence, inject the mixed solution, and then pressurize and heat treat to obtain a solid-state battery; wherein, the positive electrode is a high-nickel ternary positive electrode material, the negative electrode is a silicon-based negative electrode, the pressurization pressure is 6.5~8.9MPa, the pressurization time is 30~120s, the heat treatment temperature is 50~60℃, and the heat treatment time is 12~48h.

[0034] In order to more clearly and in detail introduce the halide / sulfide solid electrolyte material, preparation method and solid-state battery provided by the embodiments of the present invention, they will be described below in conjunction with specific embodiments.

[0035] Example 1

[0036] In this embodiment, the positive electrode comprises 92% high nickel ternary + 4% super P + 4% PVDF, and the negative electrode comprises 93% SiC + 1.5% CMC + 1.5% SBR + 4% super P;

[0037] The method for preparing a solid-state battery provided in this embodiment specifically includes the following steps:

[0038] Under argon atmosphere, a binder was prepared: 30 g of ethylene carbonate, 70 g of ethyl methyl carbonate, 30.67 g of lithium bis(trifluoromethanesulfonyl)imide, 1.71 g of lithium difluorooxalatoborate, 1.32 g of fluoroethylene carbonate, 40.11 g of methyl methacrylate, 2 g of polyethylene glycol dimethacrylate, and 0.08 g of azobisisobutyronitrile were weighed and mixed uniformly to obtain a binder, wherein the lithium salt concentration was 1.3 M, and the mass ratio of polyethylene glycol dimethacrylate, methyl methacrylate, electrolyte, and azobisisobutyronitrile was 1:20:67:0.04;

[0039] The halide Li 5.5 PS 4.5 Cl 1.5 After the powder and the above-mentioned binder are mixed, ultrasonic dispersion is performed to form a uniform mixed solution;

[0040] The positive electrode sheet, separator, and negative electrode sheet were assembled in sequence, and after the mixed solution was injected, pressurization was performed with a pressure of 6.5 MPa and a pressurization time of 60 seconds. The battery was then placed in a constant temperature oven at 50°C for activation for 20 hours to obtain a solid-state battery.

[0041] Example 2

[0042] In this embodiment, the positive electrode comprises 92% high nickel ternary + 4% super P + 4% PVDF, and the negative electrode comprises 93% SiC + 1.5% CMC + 1.5% SBR + 4% super P;

[0043] The method for preparing a solid-state battery provided in this embodiment specifically includes the following steps:

[0044] Under argon atmosphere, a binder was prepared: 30 g of ethylene carbonate, 70 g of ethyl methyl carbonate, 30.67 g of lithium bis(trifluoromethanesulfonyl)imide, 1.71 g of lithium difluorooxalatoborate, 1.32 g of fluoroethylene carbonate, 40.11 g of methyl methacrylate, 2 g of polyethylene glycol dimethacrylate, and 0.08 g of azobisisobutyronitrile were weighed and mixed uniformly to obtain a binder, wherein the lithium salt concentration was 1.5 M, and the mass ratio of polyethylene glycol dimethacrylate, methyl methacrylate, electrolyte, and azobisisobutyronitrile was 1:25:70:0.1;

[0045] The halide Li 5.5 PS 4.5 Cl 1.5 After the powder and the above-mentioned binder are mixed, ultrasonic dispersion is performed to form a uniform mixed solution;

[0046] The positive electrode sheet, separator, and negative electrode sheet were assembled in sequence, and after the mixed solution was injected, pressurization was performed with a pressure of 6.5 MPa. The battery was then placed in a constant temperature oven at 50°C for activation for 20 hours to obtain a solid-state battery.

[0047] Example 3

[0048] In this embodiment, the positive electrode comprises 92% high nickel ternary + 4% super P + 4% PVDF, and the negative electrode comprises 93% SiC + 1.5% CMC + 1.5% SBR + 4% super P;

[0049] The method for preparing a solid-state battery provided in this embodiment specifically includes the following steps:

[0050] Under argon atmosphere, a binder was prepared by weighing 30 g of ethylene carbonate, 70 g of ethyl methyl carbonate, 30.67 g of lithium bis(trifluoromethanesulfonyl)imide, 1.71 g of lithium difluorooxalatoborate, 1.32 g of fluoroethylene carbonate, 40.11 g of acrylonitrile, 2 g of poly(ethylene glycol) diacrylate, and 0.08 g of azobisisobutyronitrile, and mixing them uniformly to obtain a binder, wherein the lithium salt concentration was 1.3 M, and the mass ratio of poly(ethylene glycol) diacrylate, acrylonitrile, electrolyte, and azobisisobutyronitrile was 1:20:67:0.04;

[0051] The halide Li 5.5 PS 4.5 Cl1.5 After the powder and the above-mentioned binder are mixed, ultrasonic dispersion is performed to form a uniform mixed solution;

[0052] The positive electrode sheet, separator, and negative electrode sheet were assembled in sequence, and after the mixed solution was injected, pressurization was performed with a pressure of 6.5 MPa. The battery was then placed in a constant temperature oven at 50°C for activation for 20 hours to obtain a solid-state battery.

[0053] Example 4

[0054] In this embodiment, the positive electrode comprises 92% high nickel ternary + 4% super P + 4% PVDF, and the negative electrode comprises 93% SiC + 1.5% CMC + 1.5% SBR + 4% super P;

[0055] The method for preparing a solid-state battery provided in this embodiment specifically includes the following steps:

[0056] Under argon atmosphere, a binder was prepared: 30 g of ethylene carbonate, 70 g of ethyl methyl carbonate, 30.67 g of lithium bis(trifluoromethanesulfonyl)imide, 1.71 g of lithium difluorooxalatoborate, 1.32 g of fluoroethylene carbonate, 40.11 g of methyl methacrylate, 2 g of polyethylene glycol dimethacrylate, and 0.08 g of azobisisobutyronitrile were weighed and mixed uniformly to obtain a binder, wherein the lithium salt concentration was 1.3 M, and the mass ratio of polyethylene glycol dimethacrylate, methyl methacrylate, electrolyte, and azobisisobutyronitrile was 1:20:67:0.04;

[0057] The sulfide Li7P3S 11 After the powder and the above-mentioned binder are mixed, ultrasonic dispersion is performed to form a uniform mixed solution;

[0058] The positive electrode sheet, separator, and negative electrode sheet were assembled in sequence, and after the mixed solution was injected, pressurization was performed with a pressure of 6.5 MPa. The battery was then placed in a constant temperature oven at 50°C for activation for 20 hours to obtain a solid-state battery.

[0059] Example 5

[0060] In this embodiment, the positive electrode comprises 92% high nickel ternary + 4% super P + 4% PVDF, and the negative electrode comprises 93% SiC + 1.5% CMC + 1.5% SBR + 4% super P;

[0061] The method for preparing a solid-state battery provided in this embodiment specifically includes the following steps:

[0062] Under argon atmosphere, a binder was prepared: 30 g of ethylene carbonate, 70 g of ethyl methyl carbonate, 30.67 g of lithium bis(trifluoromethanesulfonyl)imide, 1.71 g of lithium difluorooxalatoborate, 1.32 g of fluoroethylene carbonate, 40.11 g of methyl methacrylate, 2 g of polyethylene glycol dimethacrylate, and 0.08 g of azobisisobutyronitrile were weighed and mixed uniformly to obtain a binder, wherein the lithium salt concentration was 1.3 M, and the mass ratio of polyethylene glycol dimethacrylate, methyl methacrylate, electrolyte, and azobisisobutyronitrile was 1:20:67:0.04;

[0063] After mixing the halide Li3InCl6 powder and the above-mentioned binder, ultrasonic dispersion is performed to form a uniform mixed solution;

[0064] The positive electrode sheet, separator, and negative electrode sheet were assembled in sequence, and after the mixed solution was injected, pressurization was performed with a pressure of 6.5 MPa. The battery was then placed in a constant temperature oven at 50°C for activation for 20 hours to obtain a solid-state battery.

[0065] Example 6

[0066] In this embodiment, the positive electrode includes 92% high nickel ternary + 4% super P + 4% PVDF, and the negative electrode includes 93% SiC + 1.5% CMC + 1.5% SBR + 4% super P;

[0067] The method for preparing a solid-state battery provided in this embodiment specifically includes the following steps:

[0068] Under argon atmosphere, a binder was prepared: 30 g of ethylene carbonate, 70 g of ethyl methyl carbonate, 30.67 g of lithium bis(trifluoromethanesulfonyl)imide, 1.71 g of lithium difluorooxalatoborate, 1.32 g of fluoroethylene carbonate, 40.11 g of methyl methacrylate, 2 g of polyethylene glycol dimethacrylate, and 0.08 g of azobisisobutyronitrile were weighed and mixed uniformly to obtain a binder, wherein the lithium salt concentration was 1.3 M, and the mass ratio of polyethylene glycol dimethacrylate, methyl methacrylate, electrolyte, and azobisisobutyronitrile was 1:20:67:0.04;

[0069] The sulfide Li 10 GeP2S 12 After the powder and the above-mentioned binder are mixed, ultrasonic dispersion is performed to form a uniform mixed solution;

[0070] The positive electrode sheet, separator, and negative electrode sheet were assembled in sequence, and after the mixed solution was injected, pressurization was performed with a pressure of 6.5 MPa. The battery was then placed in a constant temperature oven at 50°C for activation for 20 hours to obtain a solid-state battery.

[0071] Comparative Example 1

[0072] The positive electrode of this comparative example includes 92% high nickel ternary + 4% super P + 4% PVDF, and the negative electrode includes 93% SiC + 1.5% CMC + 1.5% SBR + 4% super P;

[0073] The preparation method of the solid-state battery provided in this comparative example specifically comprises the following steps:

[0074] Assemble the positive electrode, diaphragm, and negative electrode in sequence, and then add the halide Li 5.5 PS 4.5 Cl 1.5 The powder was prepared and the battery was pressurized to a pressure of 6.5 MPa. The battery was then placed in a constant temperature oven at 50°C for activation for 20 hours to obtain a solid-state battery.

[0075] Comparative Example 2

[0076] The positive electrode of this comparative example includes 92% high nickel ternary + 4% super P + 4% PVDF, and the negative electrode includes 93% SiC + 1.5% CMC + 1.5% SBR + 4% super P;

[0077] The preparation method of the solid-state battery provided in this comparative example specifically comprises the following steps:

[0078] Assemble the positive electrode sheet, diaphragm, and negative electrode sheet in sequence, and then add sulfide Li7P3S 11 The powder was prepared and the battery was pressurized to a pressure of 6.5 MPa. The battery was then placed in a constant temperature oven at 50°C for activation for 20 hours to obtain a solid-state battery.

[0079] Comparative Example 3

[0080] The positive electrode of this comparative example includes 92% high nickel ternary + 4% super P + 4% PVDF, and the negative electrode includes 93% SiC + 1.5% CMC + 1.5% SBR + 4% super P;

[0081] The preparation method of the solid-state battery provided in this comparative example specifically comprises the following steps:

[0082] Assemble the positive electrode sheet, separator, and negative electrode sheet in sequence, and then add sulfide Li 10 GeP2S 12 The powder was prepared and the battery was pressurized to a pressure of 6.5 MPa. The battery was then placed in a constant temperature oven at 50°C for activation for 20 hours to obtain a solid-state battery.

[0083] Comparative Example 4

[0084] The positive electrode of this comparative example includes 92% high nickel ternary + 4% super P + 4% PVDF, and the negative electrode includes 93% SiC + 1.5% CMC + 1.5% SBR + 4% super P;

[0085] The preparation method of the solid-state battery provided in this comparative example specifically comprises the following steps:

[0086] The positive electrode sheet, separator, and negative electrode sheet were assembled in sequence, and then the halide Li3InCl6 powder was added. The battery was pressurized to a pressure of 6.5 MPa, and then the battery was placed in a constant temperature oven at 50°C for activation for 20 hours to obtain a solid-state battery.

[0087] Performance Testing

[0088] Test of ionic conductivity: At 25°C, the halide / sulfide solid electrolytes prepared in Examples 1 to 6 and Comparative Examples 1 to 4 above and steel sheets were assembled into symmetrical cells. AC impedance testing was performed on an electrochemical workstation with a frequency range of 0.1 Hz to 7 MHz and an amplitude of 10 mV to obtain the bulk resistance value. The ionic conductivity was calculated by the formula. The calculated values ​​were all the overall ionic conductivity values ​​of the electrolyte and the diaphragm. The results are shown in Table 1, where the ionic conductivity calculation formula is as follows: σ=L / (R×S), where σ represents ionic conductivity in S / cm or mS / cm; L represents the thickness of the electrolyte material in cm; R represents the bulk resistance measured by the AC impedance method (EIS) in Ω; and S represents the effective conductive area of ​​the electrolyte in cm. 2 .

[0089] Cycling performance test: The solid-state batteries prepared in Examples 1 to 6 and Comparative Examples 1 to 4 were subjected to a cyclic discharge test at 25°C and 0.1C. The results of the initial charge and discharge efficiency and the capacity retention rate after 100 cycles are shown in Table 1.

[0090] Table 1 Electrochemical test results of solid-state batteries of Examples 1 to 6 and Comparative Examples 1 to 4

[0091]

[0092] As can be seen from the above, Examples 1 to 6 adopt the preparation method of the halide / sulfide solid electrolyte of the present invention. Compared with Example 1, Example 2 adjusts the lithium salt concentration and the mass ratio of each component in the binder. In Example 3, the cross-linking agent polyethylene glycol dimethacrylate is replaced by poly (ethylene glycol) diacrylate, and the monomer methyl methacrylate is replaced by acrylonitrile. In Example 4, the halide Li 5.5 PS 4.5 Cl 1.5 Powder replaced with sulfide Li7P3S 11Powder, Example 5: Halide Li 5.5 PS 4.5 Cl 1.5 The powder is replaced with the halide Li3InCl6 powder. In Example 6, the halide Li 5.5 PS 4.5 Cl 1.5 Powder replaced with Li sulfide 10 GeP2S 12 Powder; Comparative Example 1 did not use a binder, Comparative Example 2 did not use a binder and the halide Li 5.5 PS 4.5 Cl 1.5 Powder replaced with sulfide Li7P3S 11 Powder, Comparative Example 3 did not use a binder and the halide Li 5.5 PS 4.5 Cl 1.5 Powder replaced with Li sulfide 10 GeP2S 12 Powder, Comparative Example 4 did not use a binder and the halide Li 5.5 PS 4.5 Cl 1.5 The powder is replaced by halide Li3InCl6 powder; in the above embodiments and comparative examples, comparative examples 1 to 4 do not use a binder. Compared with comparative examples 1 to 4, the first-cycle coulombic efficiency, capacity retention rate after 100 cycles and ionic conductivity of the solid-state batteries prepared in embodiments 1 to 6 are significantly improved, showing good electrochemical performance, indicating that the introduction of the polymer-based binder of the present invention is beneficial to filling the pores between the halide / sulfide solid electrolytes, enhancing the compatibility with the electrode and improving the interface stability. At the same time, the elastic modulus of the polymer-based binder is better than that of the halide / sulfide solid electrolyte powder, which can alleviate the problem of rapid capacity decay caused by electrode expansion during charging and discharging; in addition, the organic group of the polymer-based binder also plays a role in improving the ionic conductivity of the electrolyte material.

[0093] The above-described embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations, modifications, evolutions, and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A halide / sulfide solid electrolyte material, characterized in that: The invention comprises a halide / sulfide solid electrolyte powder and a binder, wherein the mass ratio of the halide / sulfide solid electrolyte powder to the binder is 1:(10-100); wherein, Halide solid electrolyte powders include Li a MX6、Li b TMX4 or Li 3-c M 1-c M c Any one or more of X6, wherein M is any one or more of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, In, Zr, Hf, TM is any one or more of Co, Zn, Al, Cr, Mg, Ni, X is any one or more of F, Cl, Br, I, 2≤a≤3, 0 <b≤2,0<c<1; Sulfide solid electrolyte powder including Li 3.25 Ge 0.25 P 0.75 S4, Li 10 GeP2S 12 、Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Or any one or more of Li6PS5X, X is any one or more of Cl, Br, I; The binder includes a cross-linking agent, a monomer, an electrolyte and an initiator, and the mass ratio of the cross-linking agent, the monomer, the electrolyte and the initiator in the binder is 1:(15~30):(45~70):(0.016~0.31).

2. The halide / sulfide solid electrolyte material according to claim 1, characterized in that The monomers include any one or more of methyl acrylate, methyl methacrylate, acrylonitrile, trifluoroethyl acrylate, trifluoroethyl methacrylate, isocyanoethyl methacrylate, vinyl ethylene carbonate, and hexafluorobutyl acrylate.

3. The halide / sulfide solid electrolyte material according to claim 1, characterized in that The crosslinking agent includes any one or more of pentaerythritol acrylate, trimethylolpropane triacrylate, triallyl phosphate, polyethylene glycol dimethacrylate, poly(ethylene glycol) diacrylate, octavinyl POSS, tetra(dimethylvinylsiloxy)silane, polyethylene glycol methyl ether methacrylate, polyethylene glycol methyl ether acrylate, and polyethylene glycol dimethacrylate.

4. The halide / sulfide solid electrolyte material according to claim 1, characterized in that The electrolyte includes a lithium salt, an organic solvent and a functional additive, wherein the lithium salt concentration is 1.2~1.5M, the lithium salt includes at least one of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium dioxalatoborate, lithium difluorooxalatoborate and lithium tetrafluoroborate; the organic solvent includes ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethyl monofluoroacetate, ethyl difluoroacetate, ethyl trifluoroacetate, ethyl 3-fluoropropionate, ethyl 3,3-difluoropropionate, ethyl 3,3,3-trifluoropropionate, 4,4, Any one or more of ethyl 4-trifluorobutyrate and ethyl trifluoroacetoacetate; functional additives include any one or more of 1,3-propylene sultone, vinylene carbonate, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, sodium difluorooxalatoborate, sodium difluorooxalatophosphate, vinyl sulfate, vinyl ethylene carbonate, ethylene sulfite, 1,4-butane sultone, fluoroethylene carbonate, bisfluoroethylene carbonate, ethylene glycol bispropionitrile ether, fluoroethylene carbonate, tris(trimethylsilyl)phosphate, and tris(trimethylsilyl)borate.

5. The halide / sulfide solid electrolyte material according to claim 1, characterized in that The initiator includes any one of azobisisobutyronitrile, benzoyl peroxide, and 2,4-dichlorobenzoyl peroxide.

6. A method for preparing the halide / sulfide solid electrolyte material according to any one of claims 1 to 5, characterized in that: The following steps are involved: The halide / sulfide solid electrolyte powder and the binder are mixed and then ultrasonically dispersed.

7. Solid-state battery, characterized in that It is prepared using the halide / sulfide solid electrolyte material according to any one of claims 1 to 5.

8. The method for preparing a solid-state battery according to claim 7, wherein: The following steps are involved: The halide / sulfide solid electrolyte powder and the binder are mixed and then ultrasonically dispersed to form a uniform mixed solution; The positive electrode sheet, separator, and negative electrode sheet are assembled in sequence, and then the mixed solution is injected, followed by pressurization and heat treatment to obtain a solid-state battery. The pressurization pressure is 6.5~8.9MPa, the pressurization time is 30~120s, the heat treatment temperature is 50~60℃, and the heat treatment time is 12~48h.

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