Solid-state electrolyte, solid-state battery and preparation method

Abstract

The invention discloses a solid electrolyte, a solid battery and a preparation method, and belongs to the technical field of battery materials, the solid electrolyte comprises the following components by mass: 5-6 parts of conductive reinforced nylon powder, 5-8 parts of conductive carbon black, 5-6 parts of sodium dodecyl benzene sulfonate, 60-80 parts of polyvinylidene fluoride and 500-600 parts of N-methyl-2-pyrrolidone; the preparation method comprises the following steps: stirring and mixing conductive carbon black, sodium dodecyl benzene sulfonate, polyvinylidene fluoride, N-methyl-2-pyrrolidone and conductive reinforced nylon powder, coating a glass plate with the mixture, and drying to obtain a solid electrolyte; according to the invention, Fe-MOF with a porous structure is synthesized on the surface of the conductive carbon nanotube, so that the adsorption capacity of the conductive ionic liquid is improved, and the MOF-loaded composite carbon nanotube is compounded with the nylon powder through hydrogen-bond interaction, so that the agglomeration effect of the MOF-loaded composite carbon nanotube is reduced, a network structure is formed, and the conductive performance and the mechanical performance are enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery materials, and in particular relates to a solid electrolyte, a solid battery and a preparation method thereof. Background Art

[0002] Solid-state batteries are easy to store, highly safe, environmentally friendly and have high energy utilization efficiency. They are one of the main directions of battery research. Unlike liquid electrolytes often used in batteries and energy storage devices, solid-state batteries have solid electrodes and use ion-conductive solid electrolytes. There are many types of solid electrolytes, such as oxides, sulfides, polymers and their combinations. Oxides and sulfides have high mechanical strength and good ionic conductivity, but the interface contact of oxide solid electrolytes is poor, and the interface impedance is easily increased during the cycle, resulting in rapid battery life decay; sulfide solid electrolytes are more sensitive to water and oxygen, and are flammable, and the manufacturing process is more difficult; due to the viscoelasticity of the polymer, the impedance at the interface of polymer solid electrolytes is better than the other two solid electrolytes, but the ionic conductivity of polymers is low and the mechanical strength is poor.

[0003] Chinese invention patent application publication number CN112086678A discloses a solid-state electrolyte, its preparation method, and a solid-state battery. The solid-state electrolyte is prepared using a ceramic-based ion conductor, a polymer ion conductor, and a lithium salt; the polymer ion conductor includes a base polymer and a dopant. However, the ceramic-based electrolyte exhibits poor electrical conductivity, and the conductive active material is easily lost during cycling, impacting the lifespan of the solid-state battery. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem of how to improve the conductivity and mechanical strength of polymer solid electrolytes, and to provide a solid electrolyte, a solid-state battery and a preparation method.

[0005] The present invention improves the adsorption capacity of conductive ionic liquids by synthesizing Fe-MOF with a porous structure on the surface of conductive carbon nanotubes. By compounding the loaded MOF composite carbon nanotubes with nylon powder through hydrogen bonding, the agglomeration of the loaded MOF composite carbon nanotubes is reduced and a network structure is formed, thereby enhancing the conductive and mechanical properties of the solid electrolyte.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A solid electrolyte comprising the following components in parts by mass:

[0008] 5-6 parts of conductive reinforced nylon powder, 5-8 parts of conductive carbon black, 5-6 parts of sodium dodecylbenzenesulfonate, 60-80 parts of polyvinylidene fluoride and 500-600 parts of N-methyl-2-pyrrolidone.

[0009] Furthermore, the conductive reinforced nylon powder is prepared by the following steps:

[0010] Fe-MOF is in situ generated on the surface of carboxylated multi-walled carbon nanotubes to obtain MOF composite carbon nanotubes, and ionic liquid is loaded in the MOF composite carbon nanotubes to obtain loaded MOF composite carbon nanotubes; nylon powder is ultrasonically dispersed in a sodium hydroxide solution, and the loaded MOF composite carbon nanotubes are added after stirring. The solution is ultrasonically treated for 1-2 hours, and the precipitate is collected by centrifugation. The precipitate is washed and vacuum dried to obtain conductive enhanced nylon powder.

[0011] Furthermore, the usage ratio of nylon powder, sodium hydroxide solution, and MOF-loaded composite carbon nanotubes is 8-10 g: 100-150 mL: 3-4 g; the sodium hydroxide solution is prepared by mixing sodium hydroxide, dicyandiamide, and deionized water in a usage ratio of 2-3 g: 0.8-1 g: 50-100 mL.

[0012] Furthermore, the MOF-loaded composite carbon nanotubes are specifically prepared by the following steps:

[0013] The ionic liquid and ethanol were mixed in a reactor, and MOF composite carbon nanotubes were added, and the mixture was stirred for 1-2 hours. The ethanol was removed by rotary evaporation, and the mixture was vacuum dried to obtain MOF-loaded composite carbon nanotubes.

[0014] Furthermore, the usage ratio of the ionic liquid, ethanol and MOF composite carbon nanotubes is 0.8-1 g: 20-30 mL: 3-4 g.

[0015] Furthermore, the ionic liquid is prepared by the following steps:

[0016] In a reaction kettle, diethylmethylamine and 1-bromo-2-methoxyethane are dissolved in acetonitrile, the temperature is raised to 50-60° C. under nitrogen protection, and the reaction is carried out for 10-12 hours. The precipitate is extracted with ethanol to obtain a precipitate. The precipitate is vacuum dried and then dissolved in a 1M aqueous solution of lithium bis(trifluoromethane)sulfonyl imide. The reaction is stirred for 1-2 hours, the precipitate is extracted with dichloromethane, the precipitate is filtered, washed, and vacuum dried to obtain an ionic liquid.

[0017] Furthermore, the usage ratio of diethylmethylamine, 1-bromo-2-methoxyethane and acetonitrile is 0.8-1 g:1.5-2 g:20-30 mL.

[0018] Furthermore, MOF composite carbon nanotubes are specifically prepared by the following steps:

[0019] In a reaction kettle, carboxylated multi-walled carbon nanotubes and 2-aminoterephthalic acid are added to DMF, ultrasonically treated for 30-40 minutes, and then ferric chloride hexahydrate is added. The temperature is raised to 140-150° C. and reacted for 20-24 hours. After cooling, the precipitate is collected by centrifugation, washed, and vacuum dried to obtain MOF composite carbon nanotubes.

[0020] Furthermore, the usage ratio of carboxylated multi-walled carbon nanotubes, 2-aminoterephthalic acid, DMF and ferric chloride hexahydrate is 2-3 g: 2-4 g: 80-100 mL: 8-10 g.

[0021] Furthermore, the solid electrolyte is prepared by the following steps:

[0022] Conductive carbon black, sodium dodecylbenzenesulfonate and polyvinylidene fluoride are ultrasonically dispersed in N-methyl-2-pyrrolidone in a reactor, conductive reinforced nylon powder is added, and the mixture is stirred for 10-12 hours. The solution is coated on a glass plate with a coating thickness of 200-250 μm, and dried in an oven at 90-100° C. for 10-12 hours to obtain a solid electrolyte.

[0023] A method for preparing a solid-state battery comprises the following steps:

[0024] N-methylpyrrolidone and dimethylacetamide are mixed to prepare a mixed solvent, activated carbon and conductive carbon black are added to the mixed solvent, and slurry is obtained after stirring and grinding. The slurry is sprayed and dried, and then compacted and sliced ​​to obtain electrode sheets. The electrode sheets, solid electrolytes and lithium sheets are assembled in sequence, and after being assembled and coated with a shell, a solid-state battery is obtained.

[0025] Beneficial effects of the present invention:

[0026] 1. The present invention synthesizes Fe-MOF with a porous structure on the surface of conductive carbon nanotubes to improve the adsorption capacity of conductive ionic liquids and enhance the conductive properties of the solid electrolyte. By compounding the MOF-loaded composite carbon nanotubes with nylon powder through hydrogen bonding, the agglomeration of the MOF-loaded composite carbon nanotubes is reduced and the nylon powder is used to form a network structure, further enhancing the conductive properties of the solid electrolyte. At the same time, the conductive network formed by the nylon powder also enhances the mechanical properties of the solid electrolyte, thereby obtaining a solid electrolyte with good conductive and mechanical properties.

[0027] 2. The solid electrolyte prepared by the present invention is achieved by reacting the amino groups in 2-aminoterephthalic acid with the carboxyl groups on the surface of carboxylated multi-walled carbon nanotubes to graft 2-aminoterephthalic acid onto the surface of the carboxylated multi-walled carbon nanotubes, so that Fe-MOF with a porous structure is generated on the surface of the carboxylated multi-walled carbon nanotubes. The amino groups of Fe-MOF contained on the surface of the MOF composite carbon nanotubes produce hydrogen bonds with the amino groups formed with the diamine after the hydrolysis of the nylon powder, thereby promoting the uniform compounding of the loaded MOF composite carbon nanotubes and the nylon powder to obtain nylon powder with conductive ability. The nylon powder has a certain mechanical strength. The staggered network of the nylon powder is conducive to the formation of a conductive network, thereby improving the mechanical strength of the solid electrolyte and also improving the conductive performance of the solid electrolyte. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] Example 1: A solid electrolyte is prepared by the following steps:

[0030] S1. In a reactor, 2 g of carboxylated multi-walled carbon nanotubes and 2 g of 2-aminoterephthalic acid were added to 80 mL of DMF and ultrasonically treated for 30 min. Then, 8 g of ferric chloride hexahydrate was added, and the temperature was raised to 140°C for reaction for 20 h. After cooling, the precipitate was collected by centrifugation, washed with ethanol and deionized water, and vacuum dried at 60°C for 10 h to obtain MOF composite carbon nanotubes.

[0031] S2. In a reactor, 0.8 g of diethylmethylamine and 1.5 g of 1-bromo-2-methoxyethane were dissolved in 20 mL of acetonitrile, the temperature was raised to 50 ° C under nitrogen protection, and the reaction was carried out for 10 h. The precipitate was extracted with ethanol to obtain a precipitate, and the precipitate was vacuum dried at 50 ° C for 10 h. Then, 0.8 g of the precipitate was dissolved in 40 mL of a 1 M aqueous solution of lithium bis(trifluoromethane)sulfonyl imide, and the reaction was stirred for 1 h. The precipitate was extracted with dichloromethane, filtered to obtain the precipitate, washed with deionized water, and vacuum dried at 50 ° C for 10 h to obtain an ionic liquid.

[0032] S3. In a reactor, 0.8 g of ionic liquid and 20 mL of ethanol were mixed, 3 g of MOF-composite carbon nanotubes were added, and the mixture was stirred for 1 h. The ethanol was removed by rotary evaporation, and the mixture was vacuum dried at 50° C. for 10 h to obtain MOF-loaded composite carbon nanotubes.

[0033] S4. Ultrasonic dispersion of 8 g of 300-mesh nylon powder in 100 mL of sodium hydroxide solution was prepared by mixing sodium hydroxide, dicyandiamide, and deionized water in a ratio of 2 g:0.8 g:50 mL. After stirring for 5 min, 3 g of MOF-loaded composite carbon nanotubes was added, and ultrasonic treatment was performed for 1 h. The precipitate was collected by centrifugation, washed with ethanol and deionized water, and dried in vacuo at 60°C for 10 h to obtain conductive enhanced nylon powder.

[0034] S5. Ultrasonic disperse 5 g of conductive carbon black, 5 g of sodium dodecylbenzenesulfonate and 60 g of polyvinylidene fluoride in 500 g of N-methyl-2-pyrrolidone in a reactor, add 5 g of conductive reinforced nylon powder, stir and mix for 10 hours, apply the solution on a glass plate with a coating thickness of 200 μm, and dry in an oven at 90° C. for 10 hours to obtain a solid electrolyte.

[0035] A method for preparing a solid-state battery comprises the following steps:

[0036] N-methylpyrrolidone and dimethylacetamide are mixed in a volume ratio of 3:7 to prepare a mixed solvent, activated carbon and conductive carbon black are mixed in a mass ratio of 1:0.2 and added to the mixed solvent, and a slurry is obtained after stirring and grinding. The slurry is sprayed and dried at 90°C, and then compacted at a pressure of 8 MPa and sliced ​​to obtain electrode sheets. The electrode sheets, solid electrolytes and lithium sheets are assembled in sequence, and after being assembled and coated with a shell, a solid-state battery is obtained.

[0037] Example 2: A solid electrolyte is prepared by the following steps:

[0038] S1. In a reactor, 2.5 g of carboxylated multi-walled carbon nanotubes and 3 g of 2-aminoterephthalic acid were added to 90 mL of DMF and ultrasonically treated for 35 min. Then, 9 g of ferric chloride hexahydrate was added and the temperature was raised to 145°C for reaction for 22 h. After cooling, the precipitate was collected by centrifugation, washed with ethanol and deionized water, and vacuum dried at 65°C for 11 h to obtain MOF composite carbon nanotubes.

[0039] S2. In a reactor, 0.9 g of diethylmethylamine and 1.75 g of 1-bromo-2-methoxyethane were dissolved in 25 mL of acetonitrile, the temperature was raised to 55 ° C under nitrogen protection, and the reaction was carried out for 11 hours. The precipitate was extracted with ethanol, and the precipitate was vacuum dried at 55 ° C for 11 hours. Then, 1 g of the precipitate was dissolved in 45 mL of a 1 M aqueous solution of lithium bis(trifluoromethane)sulfonyl imide, and the reaction was stirred for 1.5 hours. The precipitate was extracted with dichloromethane, filtered to obtain the precipitate, washed with deionized water, and vacuum dried at 55 ° C for 11 hours to obtain an ionic liquid.

[0040] S3. In a reactor, 0.9 g of ionic liquid and 25 mL of ethanol were mixed, 3.5 g of MOF-composite carbon nanotubes were added, and the mixture was stirred for 1.5 h. The ethanol was removed by rotary evaporation, and the mixture was vacuum dried at 55° C. for 11 h to obtain MOF-loaded composite carbon nanotubes.

[0041] S4. Ultrasonic dispersion of 9 g of 350-mesh nylon powder in 125 mL of sodium hydroxide solution was prepared by mixing sodium hydroxide, dicyandiamide, and deionized water in a ratio of 2.5 g:0.9 g:75 mL. After stirring for 7 minutes, 3.5 g of MOF-loaded composite carbon nanotubes was added. The mixture was ultrasonically treated for 1.5 hours. The precipitate was collected by centrifugation, washed with ethanol and deionized water, and dried in vacuo at 65°C for 11 hours to obtain conductive enhanced nylon powder.

[0042] S5. In a reactor, ultrasonically disperse 6.5 g of conductive carbon black, 5.5 g of sodium dodecylbenzenesulfonate and 70 g of polyvinylidene fluoride in 550 g of N-methyl-2-pyrrolidone, add 5.5 g of conductive reinforced nylon powder, stir and mix for 11 hours, apply the solution on a glass plate with a coating thickness of 225 μm, and dry it in an oven at 95° C. for 11 hours to obtain a solid electrolyte.

[0043] A method for preparing a solid-state battery comprises the following steps:

[0044] N-methylpyrrolidone and dimethylacetamide are mixed in a volume ratio of 3.5:7.5 to prepare a mixed solvent, activated carbon and conductive carbon black are mixed in a mass ratio of 1.05:0.25 and added to the mixed solvent, and a slurry is obtained after stirring and grinding. The slurry is sprayed and dried at 95°C, and then compacted at a pressure of 9 MPa and sliced ​​to obtain electrode sheets. The electrode sheets, solid electrolytes and lithium sheets are assembled in sequence, and after being assembled and coated with a shell, a solid-state battery is obtained.

[0045] Example 3: A solid electrolyte is prepared by the following steps:

[0046] S1. In a reactor, 3 g of carboxylated multi-walled carbon nanotubes and 4 g of 2-aminoterephthalic acid were added to 100 mL of DMF and ultrasonically treated for 40 min. Then, 10 g of ferric chloride hexahydrate was added and the temperature was raised to 150°C for reaction for 24 h. After cooling, the precipitate was collected by centrifugation, washed with ethanol and deionized water, and vacuum dried at 70°C for 12 h to obtain MOF composite carbon nanotubes.

[0047] The amino groups in 2-aminoterephthalic acid react with the carboxyl groups on the surface of carboxylated multi-walled carbon nanotubes to graft 2-aminoterephthalic acid onto the surface of the carboxylated multi-walled carbon nanotubes, so that Fe-MOF with a porous structure is generated on the surface of the carboxylated multi-walled carbon nanotubes, and the surface of the MOF composite carbon nanotubes contains the amino groups of Fe-MOF.

[0048] S2. In a reactor, 1 g of diethylmethylamine and 2 g of 1-bromo-2-methoxyethane were dissolved in 30 mL of acetonitrile, the temperature was raised to 60 ° C under nitrogen protection, and the reaction was carried out for 12 h. The precipitate was extracted with ethanol, and the precipitate was vacuum dried at 60 ° C for 12 h. Then, 1.2 g of the precipitate was dissolved in 50 mL of a 1 M aqueous solution of lithium bis(trifluoromethane)sulfonyl imide, and the reaction was stirred for 2 h. The precipitate was extracted with dichloromethane, filtered to obtain the precipitate, washed with deionized water, and vacuum dried at 60 ° C for 12 h to obtain an ionic liquid.

[0049] S3. In a reactor, 1 g of ionic liquid and 30 mL of ethanol were mixed, 4 g of MOF-composite carbon nanotubes were added, and the mixture was stirred for 2 h. The ethanol was removed by rotary evaporation, and the mixture was vacuum dried at 60° C. for 12 h to obtain MOF-loaded composite carbon nanotubes.

[0050] The conductive ionic liquid is extracted into the MOF composite carbon nanotubes, and the adsorption capacity of MOF is used to adsorb the ionic liquid into the porous structure of MOF. The strong adsorption capacity of the MOF porous structure can effectively reduce the loss of the ionic liquid and enhance the conductivity.

[0051] S4. Ultrasonic dispersion of 10 g of 400-mesh nylon powder in 150 mL of sodium hydroxide solution was prepared by mixing sodium hydroxide, dicyandiamide, and deionized water in a ratio of 3 g:1 g:100 mL. After stirring for 10 min, 4 g of MOF-loaded composite carbon nanotubes was added, and ultrasonic treatment was performed for 2 h. The precipitate was collected by centrifugation, washed with ethanol and deionized water, and dried in vacuo at 70 ° C for 12 h to obtain conductive enhanced nylon powder.

[0052] The amide bonds of nylon powder are hydrolyzed in sodium hydroxide solution to form carboxyl groups and amino groups. The carboxyl groups will react rapidly with the amino groups of dicyandiamide, so that the surface of the nylon powder contains more amino groups. Then, the loaded MOF composite carbon nanotubes, which also contain amino groups on the surface, are mixed with the nylon powder. Under the action of hydrogen bonds formed between the amino groups, the loaded MOF composite carbon nanotubes and the nylon powder are promoted to be uniformly compounded, thereby obtaining nylon powder with conductive ability. The nylon powder has a certain mechanical strength. The staggered network of the nylon powder is conducive to the formation of a conductive network, which improves the mechanical strength of the solid electrolyte and also improves the conductive properties of the solid electrolyte.

[0053] S5. In a reactor, ultrasonically disperse 8 g of conductive carbon black, 6 g of sodium dodecylbenzenesulfonate and 80 g of polyvinylidene fluoride in 600 mL of N-methyl-2-pyrrolidone, add 6 g of conductive reinforced nylon powder, stir and mix for 12 h, coat the solution on a glass plate with a coating thickness of 250 μm, and dry in an oven at 100° C. for 12 h to obtain a solid electrolyte.

[0054] A method for preparing a solid-state battery comprises the following steps:

[0055] N-methylpyrrolidone and dimethylacetamide are mixed in a volume ratio of 4:8 to prepare a mixed solvent, activated carbon and conductive carbon black are mixed in a mass ratio of 1.1:0.3 and added to the mixed solvent, and a slurry is obtained after stirring and grinding. The slurry is sprayed and dried at 100°C, and then compacted at a pressure of 10 MPa and sliced ​​to obtain electrode sheets. The electrode sheets, solid electrolytes and lithium sheets are assembled in sequence, and after being assembled and coated with a shell, a solid-state battery is obtained.

[0056] The model of nylon powder is nylon 6 powder.

[0057] The diameter of carboxylated multi-walled carbon nanotubes is 10-20 nm and the length is 8-15 μm.

[0058] Comparative Example 1: The difference from Example 1 is that in S1, carboxylated multi-walled carbon nanotubes are replaced with multi-walled carbon nanotubes of equal mass, and the other steps remain unchanged to prepare a solid electrolyte.

[0059] Comparative Example 2: The difference from Example 1 is that in S2, the MOF composite carbon nanotubes are replaced with equal mass of carboxylated multi-walled carbon nanotubes, and the other steps remain unchanged to prepare a solid electrolyte.

[0060] Comparative Example 3: The difference from Example 1 is that in S5, the conductive reinforced nylon powder is replaced by an equal mass loaded MOF composite carbon nanotube, and the other steps remain unchanged to prepare a solid electrolyte.

[0061] The solid electrolytes prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were prepared into CR2025 button batteries according to the solid-state battery preparation method in Example 1. The thickness of the electrode sheet was 200 μm. The button batteries were performance tested. The discharge capacity and ionic conductivity of the batteries were tested at a current density of 0.2 C. After 500 charge and discharge cycles at room temperature (25° C.), the discharge capacity of the batteries was tested again, and the capacity retention rate of the batteries was calculated.

[0062] The tensile strength and elongation at break of the solid electrolytes prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were tested according to ASTM D882-10.

[0063] The results are shown in Table 1:

[0064] Table 1: Solid-state battery performance test results

[0065] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 <![CDATA[Ionic conductivity (S·cm -1 )]]> <![CDATA[6.58×10 -4 ]]> <![CDATA[6.67×10 -4 ]]> <![CDATA[6.74×10 -4 ]]> <![CDATA[6.02×10 -4 ]]> <![CDATA[5.52×10 -4 ]]> <![CDATA[3.92×10 -4 ]]> <![CDATA[Discharge specific capacity (mAh·g -1 )]]> 172.3 173.1 173.4 164.5 156.7 127.3 Capacity retention rate (%) 91.4 91.7 91.8 89.3 81.6 72.8 Tensile strength (MPa) 17.3 17.7 18.1 16.5 16.7 11.0 Elongation at break (%) 586 591 595 562 568 387

[0066] As can be seen from Table 1, the solid electrolyte prepared by the present invention has good mechanical properties, and the prepared solid-state battery has high ionic conductivity, high discharge specific capacity, and high capacity retention after 500 cycles, indicating that the ionic liquid in the solid electrolyte prepared by the present invention is well fixed, has strong cyclic conductivity, and the conductive network formed by the nylon powder has good conductivity.

[0067] In Comparative Example 1, since the carbon nanotube surface is not carboxylated, Fe-MOF is not uniformly generated on the carbon nanotube, the conductive synergy is poor, and the conductive performance is reduced.

[0068] In Comparative Example 2, since Fe-MOF was not synthesized on the surface of the carboxylated carbon nanotubes, the adsorption capacity of the carboxylated carbon nanotubes for the ionic liquid was poor, and the loss of the ionic liquid after multiple cycles was high, so the capacity retention rate was low.

[0069] In Comparative Example 3, since no nylon powder was added to form a conductive network, the mechanical properties of the solid electrolyte prepared were relatively low, and since the carbon nanotubes were easily agglomerated, the conductivity was also greatly reduced.

[0070] While the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A solid electrolyte, characterized in that Calculated by mass, it contains the following components: 5-6 parts of conductive reinforced nylon powder, 5-8 parts of conductive carbon black, 5-6 parts of sodium dodecylbenzenesulfonate, 60-80 parts of polyvinylidene fluoride and 500-600 parts of N-methyl-2-pyrrolidone; The conductive reinforced nylon powder is prepared by the following steps: Fe-MOF is in situ generated on the surface of carboxylated multi-walled carbon nanotubes to obtain MOF composite carbon nanotubes, and ionic liquid is loaded in the MOF composite carbon nanotubes to obtain loaded MOF composite carbon nanotubes; nylon powder is ultrasonically dispersed in a sodium hydroxide solution, and the loaded MOF composite carbon nanotubes are added after stirring. The solution is ultrasonically treated for 1-2 hours, and the precipitate is collected by centrifugation. The precipitate is washed and vacuum dried to obtain conductive enhanced nylon powder.

2. A solid electrolyte according to claim 1, characterized in that The dosage ratio of the nylon powder, the sodium hydroxide solution, and the MOF-loaded composite carbon nanotubes is 8-10 g: 100-150 mL: 3-4 g; the sodium hydroxide solution is prepared by mixing sodium hydroxide, dicyandiamide, and deionized water in a dosage ratio of 2-3 g: 0.8-1 g: 50-100 mL.

3. A solid electrolyte according to claim 2, characterized in that: The MOF-loaded composite carbon nanotubes are specifically prepared by the following steps: The ionic liquid and ethanol were mixed in a reactor, and MOF composite carbon nanotubes were added, stirred and mixed for 1-2 hours, and the ethanol was removed by rotary evaporation, and vacuum dried to obtain MOF-loaded composite carbon nanotubes; The usage ratio of the ionic liquid, ethanol and MOF composite carbon nanotubes is 0.8-1 g: 20-30 mL: 3-4 g.

4. A solid electrolyte according to claim 3, characterized in that: The ionic liquid is prepared by the following steps: In a reaction kettle, diethylmethylamine and 1-bromo-2-methoxyethane are dissolved in acetonitrile, the temperature is raised to 50-60° C. under nitrogen protection, and the reaction is carried out for 10-12 hours. The precipitate is extracted with ethanol to obtain a precipitate. The precipitate is vacuum dried and then dissolved in a 1M aqueous solution of lithium bis(trifluoromethane)sulfonyl imide. The reaction is stirred for 1-2 hours, the precipitate is extracted with dichloromethane, the precipitate is filtered, washed, and vacuum dried to obtain an ionic liquid.

5. A solid electrolyte according to claim 4, characterized in that: The usage ratio of the diethylmethylamine, 1-bromo-2-methoxyethane and acetonitrile is 0.8-1 g: 1.5-2 g: 20-30 mL.

6. A solid electrolyte according to claim 3, characterized in that: The MOF composite carbon nanotubes are specifically prepared by the following steps: In a reaction kettle, carboxylated multi-walled carbon nanotubes and 2-aminoterephthalic acid are added to DMF, ultrasonically treated for 30-40 minutes, and then ferric chloride hexahydrate is added. The temperature is raised to 140-150° C. and reacted for 20-24 hours. After cooling, the precipitate is collected by centrifugation, washed, and vacuum dried to obtain MOF composite carbon nanotubes.

7. A solid electrolyte according to claim 6, characterized in that: The usage ratio of the carboxylated multi-walled carbon nanotubes, 2-aminoterephthalic acid, DMF and ferric chloride hexahydrate is 2-3 g: 2-4 g: 80-100 mL: 8-10 g.

8. A solid electrolyte according to claim 1, characterized in that: The solid electrolyte is prepared by the following steps: Conductive carbon black, sodium dodecylbenzenesulfonate and polyvinylidene fluoride are ultrasonically dispersed in N-methyl-2-pyrrolidone in a reactor, conductive reinforced nylon powder is added, and the mixture is stirred for 10-12 hours. The solution is coated on a glass plate with a coating thickness of 200-250 μm, and dried in an oven at 90-100° C. for 10-12 hours to obtain a solid electrolyte.

9. A method for preparing a solid-state battery, characterized in that: The steps include: N-methylpyrrolidone and dimethylacetamide are mixed to prepare a mixed solvent, activated carbon and conductive carbon black are added to the mixed solvent, stirred and ground to obtain a slurry, the slurry is sprayed and dried, and then compacted and sliced ​​to obtain an electrode sheet, the electrode sheet, solid electrolyte and lithium sheet are assembled in sequence, and the solid-state battery is obtained after being assembled and coated with a shell; The solid electrolyte is the solid electrolyte according to any one of claims 1 to 8.

10. A solid-state battery, characterized in that: It is prepared by the preparation method of a solid-state battery according to claim 9.