Solid-state battery and preparation method thereof

Abstract

The invention provides a solid-state battery and a preparation method thereof. A solid state battery includes: a positive electrode including a positive electrode material; the negative electrode comprises a negative electrode current collector and a negative electrode material positioned on at least one side of the negative electrode current collector; the first solid electrolyte is positioned between the positive electrode and the negative electrode; wherein the positive electrode material comprises a polythioquinone polymer and a second solid electrolyte. According to the positive electrode material provided by the invention, under the combined action of energy level difference and pi-pi conjugation, the reaction activity between the positive electrode material and the first solid electrolyte of the solid-state battery is reduced, and the cycling stability of the battery is improved.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a solid-state battery and a method for preparing the same. Background Art

[0002] All-solid-state batteries have become the most popular secondary battery system for the next generation due to their advantages such as high safety, good stability and high energy density. According to the chemical system of the positive electrode material, all-solid-state batteries can be divided into organic all-solid-state batteries and inorganic all-solid-state batteries; compared with inorganic all-solid-state batteries, the mass ratio of active materials in the positive electrode of organic all-solid-state batteries is generally lower. This is mainly because the tap density, electronic conductivity and ion conductivity of organic electrode materials are relatively low, resulting in the corresponding composite electrodes requiring a higher proportion of solid electrolytes and conductive carbon to maintain efficient electronic and ion conduction and ensure the effective electrochemical reaction. However, this also causes a huge volume expansion of the all-solid-state battery during the cycle, thereby affecting the cycle stability of the all-solid-state battery. Summary of the invention

[0003] Purpose of the invention: The embodiment of the present application provides a solid-state battery, which improves the cycle stability of the battery.

[0004] The first aspect of the present application provides a solid-state battery, comprising:

[0005] A positive electrode, the positive electrode comprising a positive electrode material;

[0006] A negative electrode, the negative electrode comprising a negative electrode current collector and a negative electrode material located on at least one side of the negative electrode current collector;

[0007] and a first solid electrolyte disposed between the positive electrode and the negative electrode;

[0008] Wherein, the positive electrode material includes a polythioquinone polymer and a second solid electrolyte.

[0009] In some embodiments, the mass ratio of the polythioquinone polymer to the second solid electrolyte is 20-70:30-80.

[0010] In some embodiments, the first solid electrolyte has a chemical formula of: Li X PS Y Cl z R 1 w , where 2≤x≤12, 0.5≤y≤8, 0.1≤z≤3, 0≤w≤5, R 1 Any one selected from the group consisting of a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a cyano group, a sulfonic acid group, an acyl group, and a carboxyl group.

[0011] In some embodiments, the second solid electrolyte has a chemical formula of: Li a PS b Cl c R 2 d , where 2≤a≤12, 0.5≤b≤8, 0.1≤c≤3, 0.1≤d≤5, R 2 Any one selected from the group consisting of a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a cyano group, a sulfonic acid group, an acyl group, and a carboxyl group.

[0012] In some embodiments, the negative electrode material includes a composite binder and silicon powder, and the mass ratio of the composite binder to the silicon powder is 0.5-20:80-99.5.

[0013] A second aspect of the present application provides a method for preparing a solid-state battery, comprising:

[0014] preparing a positive electrode, wherein the positive electrode comprises a positive electrode material;

[0015] Prepare a negative electrode, the negative electrode comprising a negative electrode current collector and a negative electrode material located on at least one side of the negative electrode current collector;

[0016] Assembling the positive electrode, the first solid electrolyte and the negative electrode in sequence to obtain a solid-state battery;

[0017] Wherein, the positive electrode material includes a polythioquinone polymer and a second solid electrolyte.

[0018] In some embodiments, the method for preparing the polythioquinone polymer comprises:

[0019] The quinone compound and the sulfide are dissolved in a first solvent, mixed evenly, and then heated under an inert atmosphere for reaction to obtain a polythioquinone polymer.

[0020] In some embodiments, the molar mass ratio of the quinone compound to the sulfide is 1:1-10.

[0021] In some embodiments, the concentration of the quinone compound in the first solvent is 0.001 mol / L to 1 mol / L.

[0022] In some embodiments, the concentration of the sulfide in the first solvent is 0.001 mol / L to 1 mol / L.

[0023] In some embodiments, the heating temperature is 85 to 300° C., and the heating time is 1 to 24 hours.

[0024] In some embodiments, the quinone compound is selected from at least one of benzoquinone derivatives, anthraquinone derivatives, naphthoquinone derivatives, and phenanthrenequinone derivatives having an electron-donating group, and the electron-donating group is selected from any one of dialkylamino, alkylamino, amino, hydroxyl, and alkoxy.

[0025] In some embodiments, the sulfide is selected from at least one of sodium sulfide, sodium polysulfide, lithium sulfide, lithium polysulfide, selenium sulfide, cadmium sulfide, aluminum sulfide, and silver sulfide.

[0026] In some embodiments, the first solvent is selected from at least one of N,N-diisopropylethylamine, N,N-dipropylethylamine, N,N-diisopropylethylenediamine, N-isopropylethylenediamine, N-methylpyrrolidone, pyrrolidone, methylpyrrolidone, and 3-pyrrolidone.

[0027] In some embodiments, the inert atmosphere is selected from argon or nitrogen.

[0028] In some embodiments, the negative electrode material includes a composite binder and silicon powder, and the preparation method of the composite binder includes:

[0029] Dissolving the first polymerizable monomer in the second polymerizable monomer, stirring, mixing, and reacting to obtain a composite adhesive;

[0030] The mass ratio of the first polymerizable monomer to the second polymerizable monomer is 0.01-20:80-99.9.

[0031] In some embodiments, the first polymerizable monomer is selected from at least one of lithium acrylate, acrylic acid, and lithium methacrylate.

[0032] In some embodiments, the second polymerizable monomer is selected from at least one of polyethylene glycol methacrylate, polyethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol allyl methyl ether, polyethylene glycol methyl ether acrylate, and polyethylene glycol monomaleate.

[0033] The positive electrode material provided in the present application reduces the reaction activity with the first solid electrolyte in the solid-state battery under the combined effect of energy level difference and π-π conjugation, thereby improving the cycle stability of the battery. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0035] In the present specification, a numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the minimum value and the maximum value, respectively.

[0036] In a first aspect, the present application provides a solid-state battery, comprising: a positive electrode, a negative electrode, and a first solid-state electrolyte located between the positive electrode and the negative electrode, wherein the positive electrode comprises a positive electrode material; the negative electrode comprises a negative electrode current collector and a negative electrode material located on at least one side of the negative electrode current collector; wherein the positive electrode material comprises a polythioquinone polymer and a second solid-state electrolyte.

[0037] It can be understood that the positive electrode material provided in the present application, including the polythioquinone polymer and the second solid electrolyte, reduces the reaction activity with the first solid electrolyte under the combined effect of energy level difference and π-π conjugation, improves the material utilization rate of the solid-state battery, and improves the cycle stability of the battery.

[0038] In some embodiments, the mass ratio of the polythioquinone polymer to the second solid electrolyte is 20 to 70:30 to 80. Specifically, the mass ratio of the polythioquinone polymer to the second solid electrolyte can be any one of 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, or any two of the ratios.

[0039] It can be understood that the polythioquinone polymer has a long π-π conjugated structure, which can enhance the π-π interaction between molecules, reduce the spontaneous reaction of the polythioquinone polymer with the first solid electrolyte, accelerate the charge transfer rate, and improve the reaction kinetics of the positive electrode material.

[0040] In some embodiments, the first solid electrolyte has a general chemical formula: Li X PS Y Cl z R 1 w , where 2≤x≤12, 0.5≤y≤8, 0.1≤z≤3, 0≤w≤5, R 1 A fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br), an iodine atom (I), a nitro group (-NO 2 ), cyano (-CN), sulfonic acid (-SO 3H), acyl (-COR), carboxyl (-COOH). Specifically, the value of x can be any one of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or a range consisting of any two values; specifically, the value of y can be any one of 0.5, 1, 2, 3, 4, 5, 6, 7, 8 or a range consisting of any two values; specifically, the value of z can be any one of 0.1, 0.5, 1, 1.5, 2, 2.5, 3 or a range consisting of any two values; specifically, the value of w can be any one of 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or a range consisting of any two values.

[0041] It can be understood that the first solid electrolyte has lithium atoms (Li), phosphorus atoms (P), sulfur atoms (S), chlorine atoms (Cl) and first doping atoms R 1 , R 1 Selected from F, Cl, Br, I, -NO 2 、-CN、-SO 3 Any one of H, -COR, -COOH; the first doping atom R 1 As an electron-withdrawing group, the HOMO (Highest Occupied Molecular Orbital) value of the first solid electrolyte can be reduced, so that the first solid electrolyte can more easily obtain electrons and be reduced.

[0042] In some embodiments, the second solid electrolyte has a general chemical formula: Li a PS b Cl c R 2 d , where 2≤a≤12, 0.5≤b≤8, 0.1≤c≤3, 0.1≤d≤5, R 2 A fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br), an iodine atom (I), a nitro group (-NO 2 ), cyano (-CN), sulfonic acid (-SO 3H), acyl (-COR), carboxyl (-COOH). Specifically, the value of a can be any one of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or a range consisting of any two values; specifically, the value of b can be any one of 0.5, 1, 2, 3, 4, 5, 6, 7, 8 or a range consisting of any two values; specifically, the value of c can be any one of 0.1, 0.5, 1, 1.5, 2, 2.5, 3 or a range consisting of any two values; specifically, the value of d can be any one of 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or a range consisting of any two values.

[0043] It can be understood that the second solid electrolyte has lithium atoms (Li), phosphorus atoms (P), sulfur atoms (S), chlorine atoms (Cl) and second doping atoms R 2 , R 2 Selected from F, Cl, Br, I, -NO 2 、-CN、-SO 3 Any one of H, -COR, -COOH; the second doping atom R 2 It is an electron-withdrawing group, which can reduce the HOMO value of the second solid electrolyte, making it easier for the second solid electrolyte to obtain electrons and be reduced.

[0044] In some embodiments, the negative electrode material includes a composite binder and silicon powder, and the mass ratio of the composite binder to the silicon powder is 0.5-20:80-99.5. Specifically, the mass ratio of the composite binder to the silicon powder can be any one of 0.5:99.5, 1:99, 5:95, 10:90, 15:85, 20:80, or any two of the ratios.

[0045] It can be understood that the composite binder provides excellent mechanical strength and elasticity for the negative electrode material, can effectively inhibit the volume expansion of silicon, reduce the generation of cracks, and the ether bond forms an ionic conductive channel, thereby improving the ionic conductivity of the electrode, establishing an ion-electron high-speed conduction path, achieving high electronic conductivity, and improving the cycle stability of the battery; by controlling the mass ratio of the composite binder and silicon powder to 0.5-20:80-99.5, the bonding force between the negative electrode material and the negative electrode current collector can be guaranteed. At the same time, the composite binder provides excellent mechanical strength and elasticity for the negative electrode material, effectively inhibits the volume expansion of silicon, and reduces the generation of cracks.

[0046] A second aspect of the present application provides a method for preparing a solid-state battery, comprising:

[0047] Step S1: preparing a positive electrode, wherein the positive electrode comprises a positive electrode material; wherein the positive electrode material comprises a polythioquinone polymer and a second solid electrolyte;

[0048] Step S2: preparing a negative electrode, wherein the negative electrode comprises a negative electrode current collector and a negative electrode material located on at least one side of the negative electrode current collector;

[0049] Step S3: Assemble the positive electrode, the first solid electrolyte and the negative electrode in sequence to obtain a solid-state battery.

[0050] It can be understood that the positive electrode material provided in the present application, under the combined effect of energy level difference and π-π conjugation, reduces the reaction activity between the positive electrode material and the first solid electrolyte of the solid-state battery, improves the material utilization rate of the solid-state battery, and improves the cycle stability of the battery.

[0051] In some embodiments, the mass ratio of the polythioquinone polymer to the second solid electrolyte is 20 to 70:30 to 80. Specifically, the mass ratio of the polythioquinone polymer to the second solid electrolyte can be any one of 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, or any two of the ratios.

[0052] It can be understood that the polythioquinone polymer has a long π-π conjugated structure, which can enhance the π-π interaction between molecules, reduce the spontaneous reaction of the polythioquinone polymer with the first solid electrolyte, accelerate the charge transfer rate, and improve the reaction kinetics of the positive electrode material.

[0053] In some embodiments, the method for preparing a polythioquinone polymer comprises:

[0054] The quinone compound and the sulfide are dissolved in a first solvent, mixed evenly, and then heated under an inert atmosphere for reaction to obtain a polythioquinone polymer.

[0055] It can be understood that quinone compounds extend the π-π conjugated structure through polymerization reaction, which is beneficial to improve the π-π interaction between molecules, thereby reducing the spontaneous reaction between the positive electrode material and the first solid electrolyte, accelerating the charge transfer rate, and improving the reaction kinetics of the positive electrode material.

[0056] In some embodiments, after heating to react under an inert atmosphere, the method further comprises:

[0057] The second solvent is used for washing, and then drying is performed to obtain a polythioquinone polymer.

[0058] In some embodiments, the second solvent is selected from any one of methanol, distilled water, acetone, and propanol.

[0059] In some embodiments, during the drying process, the drying temperature is 60 to 150° C., and the drying time is 6 to 48 hours. Specifically, the drying temperature can be any one of 60° C., 70° C., 80° C., 90° C., 100° C., 110° C., 120° C., 130° C., 140° C., and 150° C., or a range consisting of any two values; the drying time can be any one of 6 hours, 10 hours, 15 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours, 45 hours, and 48 hours, or a range consisting of any two values.

[0060] In some embodiments, the mass ratio of the quinone compound to the sulfide is 1:1 to 10. Specifically, the mass ratio of the quinone compound to the sulfide is any one of 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 or any two of the ratios.

[0061] It is understood that quinone compounds are a class of compounds containing quinone groups. By mixing and polymerizing quinone compounds and sulfides, the quinone groups in the quinone compounds can react with the sulfur atoms in the sulfides to form new chemical bonds, thereby forming polysulfidequinone polymers.

[0062] In some embodiments, the concentration of the quinone compound in the first solvent is 0.001 mol / L to 1 mol / L. Specifically, the concentration of the quinone compound in the first solvent can be any one of 0.001 mol / L, 0.01 mol / L, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.8 mol / L, and 1 mol / L, or any two of these values.

[0063] It can be understood that by controlling the concentration of the quinone compound in the first solvent to be 0.001 mol / L to 1 mol / L, the polymerization reaction rate of the quinone compound and the sulfide can be controlled.

[0064] In some embodiments, the concentration of sulfide in the first solvent is 0.001 mol / L to 1 mol / L. Specifically, the concentration of sulfide in the first solvent can be any one of 0.001 mol / L, 0.01 mol / L, 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.8 mol / L, and 1 mol / L, or any two of these values.

[0065] It can be understood that by controlling the concentration of the sulfide in the first solvent to be 0.001 mol / L to 1 mol / L, the polymerization reaction rate of the quinone compound and the sulfide can be controlled.

[0066] In some embodiments, the heating temperature is 85 to 300° C., and the heating time is 1 to 24 hours. Specifically, the heating temperature can be any one of 85° C., 100° C., 150° C., 200° C., 250° C., and 300° C., or a range consisting of any two values; the heating time can be any one of 1 hour, 5 hours, 10 hours, 15 hours, 20 hours, and 24 hours, or a range consisting of any two values.

[0067] It can be understood that by controlling the heating temperature to 85-300° C. and the heating time to 1-24 h, the polymerization reaction of the quinone compound and the sulfide can proceed smoothly.

[0068] In some embodiments, the quinone compound is selected from at least one of benzoquinone derivatives, anthraquinone derivatives, naphthoquinone derivatives, and phenanthrenequinone derivatives having an electron-donating group, and the electron-donating group is selected from dialkylamino (-NR 2 ), alkylamino (-NHR), amino (-NH 2 ), any one of a hydroxyl group (-OH) and an alkoxy group (-OR).

[0069] It can be understood that the quinone compounds have a large number of strong electron-donating groups, which increase the LUMO (Lower Unoccupied Molecular Orbital) value, making them difficult to be reduced and easy to oxidize; at the same time, the second solid electrolyte has electron-withdrawing groups, which reduce the HOMO (Highest Occupied Molecular Orbital) value, making it easier to obtain electrons for reduction, making the LUMO of the quinone compounds much higher than the HOMO value of the second solid electrolyte, and the energy level difference between the LUMO energy level of the quinone compounds and the HOMO energy level of the second solid electrolyte is getting larger and larger (more than 2 eV), which can reduce the reaction activity between the quinone compounds and the first solid electrolyte, improve the material utilization rate of the solid-state battery, and thus improve the energy density of the solid-state battery.

[0070] In some embodiments, the sulfide is selected from at least one of sodium sulfide, sodium polysulfide, lithium sulfide, lithium polysulfide, selenium sulfide, cadmium sulfide, aluminum sulfide, and silver sulfide.

[0071] It is understood that by mixing the quinone compound and the sulfide, the quinone group in the quinone compound can react with the sulfur atom in the sulfide to form a new chemical bond, thereby forming a polythioquinone polymer.

[0072] In some embodiments, the first solvent is selected from at least one of N,N-diisopropylethylamine, N,N-dipropylethylamine, N,N-diisopropylethylenediamine, N-isopropylethylenediamine, N-methylpyrrolidone, pyrrolidone, methylpyrrolidone, and 3-pyrrolidone.

[0073] It is understood that the quinone compound and the sulfide are dissolved in the first solvent, and the first solvent should have good solubility and will not cause side reactions with the quinone compound and the sulfide.

[0074] In some embodiments, the inert atmosphere is selected from argon (Ar) or nitrogen (N 2 ).

[0075] It is understood that by polymerizing the quinone compound and the sulfide under an inert atmosphere, the polymerization reaction can be carried out more thoroughly without causing side reactions.

[0076] In some embodiments, the negative electrode material includes a composite binder and silicon powder, and the preparation method of the composite binder includes:

[0077] Dissolving the first polymerizable monomer in the second polymerizable monomer, stirring, mixing, and reacting to obtain a composite adhesive;

[0078] The mass ratio of the first polymerized monomer to the second polymerized monomer is 0.01-20:80-99.5. Specifically, the mass ratio of the first polymerized monomer to the second polymerized monomer can be any one of 0.5:99.5, 1:99, 5:95, 10:90, 15:85, 20:80 or any two of the ratios.

[0079] It can be understood that the first polymerized monomer provides a hard segment, and the second polymerized monomer provides a soft segment. The hard and soft combination of the hard segment acrylic acid and the soft segment poly (ethylene glycol) methacrylate makes the composite adhesive have excellent mechanical strength and elasticity, effectively inhibits the volume expansion of silicon, and reduces the generation of cracks; the ether bond forms a conductive channel for lithium ions, improves the lithium ion conductivity of the electrode, and the lithium nanoparticles and the negative electrode current collector achieve high electronic conductivity; at the same time, a three-dimensional continuous conductive network is formed inside the silicon negative electrode, which promotes the uniform transmission of lithium ions.

[0080] In some embodiments, the first polymerizable monomer is selected from at least one of lithium acrylate, acrylic acid, and lithium methacrylate.

[0081] In some embodiments, the second polymerizable monomer is selected from at least one of polyethylene glycol methacrylate, polyethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol allyl methyl ether, polyethylene glycol methyl ether acrylate, and polyethylene glycol monomaleate.

[0082] In some embodiments, the present application also provides a method for preparing a positive electrode, comprising:

[0083] The polythioquinone polymer and the second solid polymer are mixed, ground, dispersed, and pressed under a first pressure to form a positive electrode.

[0084] In some specific embodiments, the grinding time is 10 to 20 minutes. Specifically, the grinding time can be any one of 10 minutes, 12 minutes, 14 minutes, 16 minutes, 18 minutes, and 20 minutes, or a range consisting of any two values.

[0085] In some specific embodiments, the first pressure ranges from 125 to 130 MPa, and the pressing time ranges from 1 to 3 min. Specifically, the first pressure ranges from 125 MPa, 126 MPa, 127 MPa, 128 MPa, 129 MPa, and 130 MPa, or any two of them; the pressing time ranges from 1 min, 2 min, and 3 min, or any two of them.

[0086] In some embodiments, the present application also provides a method for preparing a negative electrode, comprising:

[0087] Dissolving the composite binder and silicon powder in a third solvent, stirring and mixing, to obtain a negative electrode slurry;

[0088] The negative electrode slurry is coated on at least one side of the negative electrode current collector and dried to obtain a negative electrode.

[0089] In some specific embodiments, the third solvent is selected from any one of N,N-dimethylformamide, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, pyrrolidone, tetrahydrofuran, methylpyrrolidone, and 3-pyrrolidone.

[0090] In some embodiments, the present application also provides a method for preparing a solid electrolyte, comprising:

[0091] Stirring and mixing lithium atoms (Li), phosphorus atoms (P), sulfur atoms (S), chlorine atoms (Cl) and dopant atoms to obtain a mixture;

[0092] The mixture is pressed under a second pressure to obtain a solid electrolyte.

[0093] In some specific embodiments, the second pressure ranges from 125 to 130 MPa, and the pressing time ranges from 2 to 5 min. Specifically, the second pressure ranges from 125 MPa, 126 MPa, 127 MPa, 128 MPa, 129 MPa, and 130 MPa, or any two of them; the pressing time ranges from 2 min, 3 min, 4 min, and 5 min, or any two of them.

[0094] The present application is described below in conjunction with specific embodiments.

[0095] Example 1

[0096] Preparation of positive electrode material: Weigh 0.0015 mol / L of 2,3,5,6-tetra(amino)benzoquinone and 0.0015 mol / L of sodium sulfide, dissolve them in N-methylpyrrolidone and mix them evenly, then heat them at 180°C for 6 h under Ar atmosphere, wash them with propanol, and finally dry them at 85°C for 12 h to obtain a polythioquinone polymer.

[0097] Preparation of the first solid electrolyte: weigh 120 mg Li 5.3 PS 4.3 ClBr 0.7 , and pressed at 128 MPa for 2 min to form the first solid electrolyte.

[0098] Prepare the second solid electrolyte: weigh 120 mg Li 5.3 PS 4.3 ClBr 0.7 , and press at 128 MPa for 2 min to form the second solid electrolyte. Prepare the positive electrode: weigh 130 mg of polythioquinone polymer and the second solid electrolyte Li 5.3 PS 4.3 ClBr 0.7 (Polythioquinone polymer and second solid electrolyte Li 5.3 PS 4.3 ClBr 0.7 The mixture was mixed with 240 mg / ml of 1% 2-nitropropene (with a mass ratio of 45:55), ground in a mortar for 15 min to make it uniformly dispersed; and pressed at 128 MPa for 1 min to form a positive electrode.

[0099] Preparation of composite adhesive: Weigh 1g of lithium acrylate and poly(ethylene glycol) methacrylate (the mass ratio of lithium acrylate to poly(ethylene glycol) methacrylate is 10:90), dissolve lithium acrylate in poly(ethylene glycol) methacrylate, stir evenly and wait for full polymerization to obtain composite adhesive.

[0100] Preparation of negative electrode: weigh 100 mg of composite binder and silicon powder (mass ratio of composite binder to silicon powder is 15:85) and stir evenly in N, N-dimethylformamide to obtain negative electrode slurry;

[0101] The negative electrode slurry is coated on the negative electrode current collector and dried to obtain the negative electrode.

[0102] Preparation of an all-solid-state battery: In a glove box filled with argon, the positive electrode shell, aluminum, the positive electrode, the first solid electrolyte, the negative electrode, and the negative electrode shell are assembled and sealed in a CR2016 button cell in sequence to obtain an all-solid-state battery.

[0103] The preparation method of Example 2 is the same as that of Example 1, except that: the polythioquinone polymer and the second solid electrolyte Li 5.3 PS 4.3 ClBr0.7 The mass ratio is 50:50.

[0104] The preparation method of Example 3 is the same as that of Example 1, except that: the polythioquinone polymer and the second solid electrolyte Li 5.3 PS 4.3 ClBr 0.7 The mass ratio is 55:45.

[0105] The preparation method of Example 4 is the same as that of Example 1, except that: the second solid electrolyte is 120 mg Li 5.3 PS 4.3 C1I 0.7 , polythioquinone polymer and second solid electrolyte Li 5.3 PS 4.3 I 0.7 The mass ratio is 45:55.

[0106] The preparation method of Example 5 is the same as that of Example 1, except that: the second solid electrolyte is Li 5.3 PS 4.3 Cl(NO 2 ) 0.7 , polythioquinone polymer and second solid electrolyte Li 5.3 PS 4.3 Cl(NO 2 ) 0.7 The mass ratio is 45:55.

[0107] The preparation method of Example 6 is the same as that of Example 1, except that the quinone compound is 2,3,5,6-tetrakis(hydroxy)-p-benzoquinone.

[0108] The preparation method of Example 7 is the same as that of Example 1, except that the mass ratio of the composite binder to the silicon powder is 10:90.

[0109] The preparation method of Example 8 is the same as that of Example 1, except that the mass ratio of the composite binder to the silicon powder is 5:95;

[0110] The preparation method of Comparative Example 1 is the same as that of Example 1, except that the positive electrode material is 2,3,5,6-tetrakis(amino)-p-benzoquinone.

[0111] The preparation method of Comparative Example 2 is the same as that of Example 1, except that the negative electrode material is silicon powder.

[0112] The preparation method of Comparative Example 3 is the same as that of Example 1, except that the second solid electrolyte is Li 5.3 PS 4.3 Cl, polythioquinone polymer and second solid electrolyte Li 5.3 PS 4.3The mass ratio of Cl is 45:55.

[0113] Test method:

[0114] (1) First-effect test method: At 35±3℃, discharge the battery to 1.5V at a constant current of 0.05C, and record the discharge capacity as D 1 , 0.05C constant current charge to 3.5V, constant voltage 3.5V charge to the cut-off current 0.05C, record the charging capacity as C 1 , then; first effect = (C 1 / D 1 )×100%, calculate the ratio of discharge capacity to charge capacity to get the first efficiency.

[0115] (2) First cycle discharge capacity and capacity retention rate: At 35±3℃, the battery was discharged to 1.5V at a constant current of 0.1C. The discharge capacity was recorded as C 1 Then charge at a constant current of 0.1C to 3.5V, charge at a constant voltage of 3.5V to a cut-off current of 0.05C, repeat the charge and discharge steps for N weeks, and obtain the discharge capacity C of the Nth week. N , Nth cycle capacity retention rate = (C N / C 1 )×100%, and obtain the first cycle discharge capacity and capacity retention rate.

[0116] Note: If the capacity retention rate is lower than 80% and the coulombic efficiency is lower than 98%, the battery test is stopped.

[0117] Table 1 shows the parameter settings of Examples 1 to 8 and Comparative Examples 1 to 3

[0118]

[0119]

[0120]

[0121] Table 2 is the test results of Examples 1 to 8 and Comparative Examples 1 to 3

[0122]

[0123]

[0124] Result analysis:

[0125] Comparing Examples 1 to 8 with Comparative Example 1, it can be seen from the test results of Table 2 that the capacity retention rate of the solid-state battery prepared in Comparative Example 1 at the 70th cycle is 80.19%, which does not reach a capacity retention rate of more than 80% at the 100th cycle, while the capacity retention rate of the solid-state batteries prepared in Examples 1 to 8 at the 100th cycle is approximately 90% or more, indicating that the present application can reduce the reaction activity between the quinone compound and the first solid electrolyte by first mixing the polythioquinone polymer and the second solid electrolyte to prepare the positive electrode material, thereby improving the cycle stability of the solid-state battery.

[0126] Comparing Examples 1 to 8 with Comparative Example 2, it can be seen from the test results of Table 2 that the capacity retention rate of the solid-state battery prepared in Comparative Example 2 at the 70th cycle is 85.72%, while the capacity retention rate of the solid-state battery prepared in Examples 1 to 8 at the 100th cycle is approximately 90% or above, indicating that the present application prepares the negative electrode material by mixing the composite binder and silicon powder, and the composite binder provides excellent mechanical strength and elasticity for the negative electrode material, effectively inhibits the volume expansion of silicon, reduces the generation of cracks, and can improve the cycle stability of the solid-state battery.

[0127] Comparing Examples 1 to 8 with Comparative Example 3, it can be seen from the test results of Table 2 that the 100th cycle capacity retention rate of the solid-state battery prepared in Comparative Example 3 is 87.92%, while the 100th cycle capacity retention rate of the solid-state battery prepared in Examples 1 to 8 is about 90% or more, indicating that the present application introduces electron-withdrawing groups on the second solid electrolyte to increase the energy level difference between the LUMO energy level of the quinone compound and the HOMO energy level of the second solid electrolyte, thereby reducing the reaction activity between the quinone compound and the first solid electrolyte and improving the cycle stability of the solid-state battery.

[0128] In summary, although the embodiments of the present application are described in detail above, the above embodiments are not intended to limit the present application, and ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A solid-state battery, characterized in that: include: A positive electrode, the positive electrode comprising a positive electrode material; A negative electrode, the negative electrode comprising a negative electrode current collector and a negative electrode material located on at least one side of the negative electrode current collector; and a first solid electrolyte disposed between the positive electrode and the negative electrode; Wherein, the positive electrode material includes a polythioquinone polymer and a second solid electrolyte.

2. The solid-state battery according to claim 1, characterized in that: The mass ratio of the polythioquinone polymer to the second solid electrolyte is 20-70:30-80.

3. The solid-state battery according to claim 1, characterized in that: The chemical formula of the first solid electrolyte: Li X PS Y Cl z R 1 w , Among them, 2≤x≤12, 0.5≤y≤8, 0.1≤z≤3, 0≤w≤5, R 1 Any one selected from the group consisting of a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a cyano group, a sulfonic acid group, an acyl group, and a carboxyl group; and / or, The chemical formula of the second solid electrolyte is: Li a PS b Cl c R 2 d , where 2≤a≤12, 0.5≤b≤8, 0.1≤c≤3, 0.1≤d≤5, R 2 Any one selected from the group consisting of a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a nitro group, a cyano group, a sulfonic acid group, an acyl group, and a carboxyl group.

4. The solid-state battery according to claim 1, characterized in that: The negative electrode material comprises a composite binder and silicon powder, and the mass ratio of the composite binder to the silicon powder is 0.5-20:80-99.

5.

5. A method for preparing a solid-state battery, characterized in that: include: preparing a positive electrode, wherein the positive electrode comprises a positive electrode material; Prepare a negative electrode, the negative electrode comprising a negative electrode current collector and a negative electrode material located on at least one side of the negative electrode current collector; Assembling the positive electrode, the first solid electrolyte and the negative electrode in sequence to obtain a solid-state battery; Wherein, the positive electrode material includes a polythioquinone polymer and a second solid electrolyte.

6. The method for preparing a solid-state battery according to claim 5, characterized in that: The preparation method of the polythioquinone polymer comprises: The quinone compound and the sulfide are dissolved in a first solvent, mixed evenly, and then heated under an inert atmosphere for reaction to obtain a polythioquinone polymer.

7. The method for preparing a solid-state battery according to claim 6, characterized in that: The mass ratio of the quinone compound to the sulfide is 1:1 to 10; and / or, The concentration of the quinone compound in the first solvent is 0.001 mol / L to 1 mol / L; and / or, The concentration of the sulfide in the first solvent is 0.001 mol / L to 1 mol / L; and / or, The heating temperature is 85 to 300° C., and the heating time is 1 to 24 hours.

8. The method for preparing a solid-state battery according to claim 7, characterized in that: The quinone compound is selected from at least one of benzoquinone derivatives, anthraquinone derivatives, naphthoquinone derivatives and phenanthrenequinone derivatives having an electron-donating group, and the electron-donating group is selected from any one of dialkylamino, alkylamino, amino, hydroxyl and alkoxy; and / or, The sulfide is selected from at least one of sodium sulfide, sodium polysulfide, lithium sulfide, lithium polysulfide, selenium sulfide, cadmium sulfide, aluminum sulfide and silver sulfide; and / or, The first solvent is selected from at least one of N,N-diisopropylethylamine, N,N-dipropylethylamine, N,N-diisopropylethylenediamine, N-isopropylethylenediamine, N-methylpyrrolidone, pyrrolidone, methylpyrrolidone, and 3-pyrrolidone; and / or, The inert atmosphere is selected from argon or nitrogen.

9. The method for preparing a solid-state battery according to claim 5, characterized in that: The negative electrode material includes a composite binder and silicon powder, and the preparation method of the composite binder includes: Dissolving the first polymerizable monomer in the second polymerizable monomer, stirring, mixing, and reacting to obtain a composite adhesive; The mass ratio of the first polymerizable monomer to the second polymerizable monomer is 0.01-20:80-99.

5.

10. The method for preparing a solid-state battery according to claim 9, characterized in that: The first polymerizable monomer is selected from at least one of lithium acrylate, acrylic acid, and lithium methacrylate; and / or, The second polymerizable monomer is selected from at least one of polyethylene glycol methacrylate, polyethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol allyl methyl ether, polyethylene glycol methyl ether acrylate, and polyethylene glycol monomaleate.

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