Polymer solid electrolyte, preparation method thereof and solid-state battery

Abstract

The invention relates to a polymer solid electrolyte, a preparation method thereof and a solid-state battery, the polymer solid electrolyte comprises a polymer, a metal sodium salt and an additive, and the additive is phenylboronic acid functionalized nano silicon dioxide. The invention also provides a solid-state battery comprising the polymer solid-state electrolyte. The MSN-CFPBA is prepared through grafting modification, so that silicon dioxide is functionalized, and the comprehensive performance of the polymer electrolyte is improved. B atoms in a CFBBA molecular structure have Lewis acidity and can be coordinated and interacted with salt anions (such as TFSI-, PF6-and the like), the acting force between the anions and sodium ions is weakened, dissociation and migration of sodium salt are promoted, and meanwhile, the mechanical strength of the electrolyte can be improved and growth of dendritic crystals can be effectively inhibited in the presence of a proper content of nano silicon dioxide. The polymer electrolyte provided by the invention has high ionic conductivity, excellent interface stability and relatively good mechanical property, and is suitable for a high-energy-density solid metal sodium battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid electrolytes, and particularly relates to a polymer solid electrolyte, a preparation method thereof, and a solid-state battery. Background Art

[0002] In recent years, the market application scenarios of lithium-ion batteries have been rapidly broadened, from portable consumer electronics to electric vehicles and energy storage systems, and the application scenarios of lithium batteries have been continuously expanding. However, the scarcity of lithium resources and high production costs limit its further development. In contrast, sodium-ion batteries have received extensive attention in recent years due to their rich resources, low cost, environmental friendliness, and electrochemical characteristics similar to those of lithium-ion batteries, and have become a new choice in the field of electrochemical energy storage.

[0003] Compared with other batteries, sodium-ion batteries have the advantages of long cycle life, lower cost, high safety, and rich reserves. Along with the rise of the wave of solid-state batteries, all-solid-state batteries have gradually become a research hotspot. All-solid-state batteries use solid electrolytes to replace traditional liquid organic electrolytes, which not only increases the safety of the batteries, but also can greatly improve the energy density of the batteries and extend the service life of the batteries.

[0004] Polymer solid electrolytes have the advantages of high flexibility, good film-forming property, low cost, easy dissolution of lithium salts, and good compatibility with electrode interfaces. However, PEO-based electrolytes still have the following problems in practical applications: the ion conduction of PEO-based electrolytes mainly depends on the movement of polymer segments. At room temperature, the crystallinity of PEO is relatively high, resulting in restricted segment movement, and the ionic conductivity is usually lower than 10 -5 S / cm, which cannot meet the requirements of actual battery applications; secondly, the high flexibility of the polymer also brings the problem of weak mechanical strength, resulting in difficulty for polymer electrolytes to effectively inhibit the growth of dendrites; in addition, the electrochemical oxidation window of the polymer is relatively narrow, and it is prone to oxidative decomposition at high voltages, limiting its application in high-energy-density batteries. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems of low ionic conductivity of PEO and unstable interface formed between PEO and lithium metal, and to provide a polymer solid electrolyte, a preparation method thereof, and a solid-state battery. The present invention uses a composite material of phenylboronic acid-functionalized silica as an additive for the polymer electrolyte to improve the dispersion and compatibility of solid fillers in the polymer matrix, effectively reduce the crystallinity of the polymer, and improve the overall ionic conductivity and mechanical strength of the electrolyte.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A preparation method of a polymer solid electrolyte, the method is:

[0008] Step 1: Pretreatment of the silica surface: Disperse nano-silica in dilute hydrochloric acid to form a solution with a concentration of 0.1 - 1.0 g / mL, ultrasonically treat for 30 min to remove surface impurities, wash with deionized water until neutral, dry at 80 - 120 °C for 4 - 10 h, and then calcine at 400 - 600 °C for 1 - 5 h to activate the surface hydroxyl groups;

[0009] Step 2: Ultrasonically disperse the activated nano-silica in anhydrous toluene, then add 3-cyano-4-fluorobenzeneboronic acid (CFBBA), stir and mix evenly, and heat under reflux at 60 - 80 °C for 6 - 16 h;

[0010] Step 3: After the reaction is completed, cool and centrifuge for 30 min, remove the upper clear liquid, wash the lower precipitate three times with a mixed solution of anhydrous toluene and water (volume ratio 1:1), transfer to a vacuum drying oven and dry overnight at 60 °C to obtain 3-cyano-4-fluorobenzeneboronic acid-modified nano-silica (MSN-CFPBA);

[0011] Step 4: Dissolve the metal sodium salt, 3-cyano-4-fluorobenzeneboronic acid-modified nano-silica (MSN-CFPBA), and the polymer substrate in a polar solvent in sequence and stir evenly to obtain a homogeneous solution;

[0012] Step 5: Uniformly scrape the obtained homogeneous solution onto a polytetrafluoroethylene template, transfer to a vacuum drying oven and dry thoroughly to obtain a polymer solid electrolyte.

[0013] Further, in Step 1, the concentration of the dilute hydrochloric acid is 1 M; the concentration of the solution is 0.2 - 0.6 g / mL, preferably 0.4 g / mL; the drying condition is drying at 100 °C for 6 h; the calcination condition is calcination at 500 °C for 2 h.

[0014] Further, in Step 2, the mass ratio of the nano-silica to 3-cyano-4-fluorobenzeneboronic acid is 1:2, and the concentration of the reflux solution is 0.05 - 0.2 g / mL, preferably 0.1 g / mL.

[0015] Further, in Step 2, the reflux condition is refluxing at 80 °C for 12 h.

[0016] Further, in step four, the metal sodium salt is one or more of sodium hexafluorophosphate (NaPF4), sodium perchlorate (NaClO4), sodium difluoro(oxalato)borate (NaDFOB), sodium tetrafluoroborate (NaBF4), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), and sodium bis(fluorosulfonyl)imide (NaFSI); the material of the polymer substrate is one or more of polyethylene oxide (PEO), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polymethyl methacrylate (PMMA), and polyacrylonitrile (PAN); the polar solvent is acetonitrile or dimethyl sulfoxide; in the homogeneous solution, the molar ratio of the metal sodium salt to the polymer substrate is 1:16, and the mass ratio of MSN-CFPBA to the polymer substrate is 0.02-1:10.

[0017] Further, in step five, the drying temperature is 60 °C and the time is 10-36 h.

[0018] A polymer solid electrolyte prepared by the above preparation method.

[0019] A solid-state battery, the solid-state battery includes the above polymer solid electrolyte, the solid-state battery includes a sodium negative electrode, a polymer solid electrolyte material, and a positive electrode material; the positive electrode material is at least one of sodium iron phosphate, sodium vanadium phosphate, sodium titanium phosphate, sodium iron sulfate, sodium iron pyrophosphate, sodium ion fluorophosphate, sodium manganese oxide, and sodium vanadium fluorophosphate.

[0020] The beneficial effects of the present invention compared with the prior art are as follows:

[0021] (1) In the polymer solid electrolyte provided by the present invention, nano-silica grafted with CFPBB (MSN-CFPBA) is a functional filler additive. On the one hand, the boron atom in the molecular structure has an empty orbital and can accept electron pairs, so it exhibits Lewis acidity and can coordinate with salt anions (TFSI - , PF6 - etc.) to occur coordination interactions, weaken the interaction force between anions and sodium ions, promote the dissociation and migration of sodium salts. On the other hand, the uniformity of the benzene boronic acid-functionalized SiO2 dispersed in the polymer substrate is improved, realizing a higher degree of two-phase compatibility. The growth of dendrites can be effectively inhibited under the appropriate addition amount of MSN-CFPBA; most importantly, the introduction of MSN-CFPBA reduces the crystallinity of the polymer substrate, enhances the movement ability of polymer segments, and significantly improves the ionic conductivity of the electrolyte.

[0022] (2) The cyano group (-CN) and fluorine atom (-F) in the CFBBA molecular structure are strong electron-withdrawing groups. The two can reduce the highest occupied molecular orbital (HOMO) energy level of the electrolyte through inductive effect and conjugate effect, thereby improving the antioxidant ability of the polymer electrolyte. This makes the modified electrolyte have a wider electrochemical window, capable of matching high-voltage cathode materials and applicable to high-energy density battery systems;

[0023] (3) During the reduction process, the fluorine (F) on the benzene ring of the additive MSN-CFPBA reacts with sodium ions (Na + ) to form NaF. NaF is a highly stable inorganic component, which can not only effectively enhance the mechanical strength and chemical stability of the SEI layer. Moreover, NaF has good ionic conductivity and can promote the transport of sodium ions (Na + ) in the SEI layer, thereby reducing the interfacial impedance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a reaction schematic diagram of the phenylboronic acid functionalization grafted on the silica surface of the present invention;

[0025] Figure 2 It is a multi-rate charge and discharge curve diagram of the solid electrolyte of Example 1 of the present invention paired with a sodium iron pyrophosphate phosphate battery;

[0026] Figure 3 It is a multi-rate charge and discharge curve diagram of the solid electrolyte of Example 2 of the present invention paired with a sodium iron pyrophosphate phosphate battery;

[0027] Figure 4 It is a multi-rate charge and discharge curve diagram of the solid electrolyte of Example 3 of the present invention paired with a sodium iron pyrophosphate phosphate battery;

[0028] Figure 5 It is a multi-rate charge and discharge curve diagram of the solid electrolyte of Example 4 of the present invention paired with a sodium iron pyrophosphate phosphate battery;

[0029] Figure 6 It is a multi-rate charge and discharge curve diagram of the solid electrolyte of Comparative Example 1 of the present invention paired with a sodium iron pyrophosphate phosphate battery. DETAILED DESCRIPTION OF THE INVENTION

[0030] The technical solutions of the present invention will be further described below in conjunction with the drawings and embodiments, but are not limited thereto. Any modification or equivalent replacement of the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention shall be covered by the protection scope of the present invention.

[0031] The present invention uses a silica-grafted phenylboronic acid composite material as a filler for a pure polymer solid electrolyte, improving the dispersion uniformity of the filler in the polymer matrix, reducing the crystallinity of the PEO solid electrolyte, and enhancing the ionic conductivity of the electrolyte membrane. Meanwhile, during the charge and discharge process of the battery, it promotes the stable formation of a lithium metal / electrolyte interface rich in NaF, improving the long-cycle and rate performance of the PEO-based solid battery, and having potential application prospects.

[0032] In the present invention, MSN-CFPBA is prepared by grafting modification to functionalize silica, so as to improve the comprehensive performance of the polymer electrolyte. The B atom in the CFBBA molecular structure has Lewis acidity and can undergo coordination interactions with salt anions (such as TFSI - , PF6 - etc.), weakening the force between the anion and sodium ion, promoting the dissociation and migration of sodium salts. Meanwhile, the presence of an appropriate amount of nano-silica can improve the mechanical strength of the electrolyte and effectively inhibit the growth of dendrites. In addition, the cyano group (-CN) and fluorine atom (-F) in the CFBBA molecule, as strong electron-withdrawing groups, reduce the HOMO energy level of the electrolyte through inductive effect and conjugation effect, improve the antioxidant ability, broaden the electrochemical window, and match the high-voltage cathode material. The polymer electrolyte provided by the present invention has high ionic conductivity, excellent interfacial stability and good mechanical properties, and is applicable to high-energy-density solid-state sodium metal batteries.

[0033] Example 1

[0034] A preparation method of a polymer solid electrolyte includes the following steps:

[0035] Disperse 2.0 g of nano-silica in 1 M dilute hydrochloric acid, ultrasonically treat for 30 min to remove surface impurities, then wash with deionized water until neutral, dry at 100 °C for 6 h, and then calcine the dried product at 500 °C for 2 h to activate the surface hydroxyl groups;

[0036] Take 1 g of the activated nano-silica and ultrasonically disperse it in 30 ml of anhydrous toluene, then add 2 g of 3-cyano-4-fluorophenylboronic acid (CFBBA), stir and mix evenly, and heat under reflux at 80 °C for 12 h;

[0037] After the reaction is completed, cool and centrifuge for 30 min, remove the upper clear liquid, wash the lower precipitate three times with a mixed solution of anhydrous toluene and water (volume ratio 1:1), transfer it to a vacuum drying oven and dry overnight at 60 °C to obtain 3-cyano-4-fluorophenylboronic acid-modified nano-silica (MSN-CFPBA);

[0038] Mix sodium salt NaTFSI, MSN-CFPBA and PEO matrix (n NaTFSI :n PEO= 1:16, m MSN-CFPBA :m PEO (= 0.05:10) were successively dissolved in anhydrous acetonitrile and stirred at room temperature for 24 h to obtain a homogeneous solution;

[0039] The homogeneous solution was spin-coated on a polytetrafluoroethylene template and transferred to a vacuum drying oven, dried at 60 °C for 24 h to obtain PEO-0.5% MSN-CFPBA.

[0040] Example 2

[0041] 2.0 g of nano-silica was dispersed in 1 M dilute hydrochloric acid, sonicated for 30 min to remove surface impurities, then washed with deionized water until neutral, dried at 100 °C for 6 h, and then the dried product was calcined at 500 °C for 2 h to activate the surface hydroxyl groups;

[0042] 1 g of the activated nano-silica was ultrasonically dispersed in 30 ml of anhydrous toluene, and then 2 g of 3-cyano-4-fluorobenzeneboronic acid (CFBBA) was added, stirred and mixed evenly, and heated under reflux at 80 °C for 12 h;

[0043] After the reaction was completed, it was cooled and centrifuged for 30 min to remove the upper clear liquid. The lower precipitate was washed three times with a mixed solution of anhydrous toluene and water (volume ratio 1:1), and transferred to a vacuum drying oven and dried overnight at 60 °C to obtain 3-cyano-4-fluorobenzeneboronic acid modified nano-silica (MSN-CFPBA);

[0044] The sodium salt NaTFSI, MSN-CFPBA and PEO substrate (n NaTFSI :n PEO = 1:16, m MSN-CFPBA :m PEO = 0.1:10) were successively dissolved in anhydrous acetonitrile and stirred at room temperature for 24 h to obtain a homogeneous solution;

[0045] The homogeneous solution was spin-coated on a polytetrafluoroethylene template and transferred to a vacuum drying oven, dried at 60 °C for 24 h to obtain PEO-1.0% MSN-CFPBA.

[0046] Example 3

[0047] 2.0 g of nano-silica was dispersed in 1 M dilute hydrochloric acid, sonicated for 30 min to remove surface impurities, then washed with deionized water until neutral, dried at 100 °C for 6 h, and then the dried product was calcined at 500 °C for 2 h to activate the surface hydroxyl groups;

[0048] 1 g of the activated nano-silica was ultrasonically dispersed in 30 ml of anhydrous toluene, and then 2 g of 3-cyano-4-fluorobenzeneboronic acid (CFBBA) was added, stirred and mixed evenly, and heated under reflux at 80 °C for 12 h;

[0049] After the reaction was completed, it was cooled and centrifuged for 30 min. The upper clear liquid was removed, and the lower precipitate was washed three times with a mixed solution of anhydrous toluene and water (volume ratio 1:1), and then transferred to a vacuum drying oven for overnight drying at 60 °C to obtain silica nanoparticles modified with 3-cyano-4-fluorobenzeneboronic acid (MSN-CFPBA).

[0050] The sodium salt NaTFSI, MSN-CFPBA and PEO substrate (n NaTFSI :n PEO = 1:16, m MSN-CFPBA :m PEO = 0.2:10) were successively dissolved in anhydrous acetonitrile and stirred at room temperature for 24 h to obtain a homogeneous solution.

[0051] The homogeneous solution was spin-coated on a polytetrafluoroethylene template and transferred to a vacuum drying oven for drying at 60 °C for 24 h to obtain PEO-2.0% MSN-CFPBA.

[0052] Example 4

[0053] 2.0 g of silica nanoparticles were dispersed in 1 M dilute hydrochloric acid, sonicated for 30 min to remove surface impurities, then washed with deionized water until neutral, dried at 100 °C for 6 h, and then the dried product was calcined at 500 °C for 2 h to activate the surface hydroxyl groups.

[0054] 1 g of the activated silica nanoparticles was ultrasonically dispersed in 30 ml of anhydrous toluene, then 2 g of 3-cyano-4-fluorobenzeneboronic acid (CFBBA) was added, and the mixture was stirred and mixed evenly, and heated under reflux at 80 °C for 12 h.

[0055] After the reaction was completed, it was cooled and centrifuged for 30 min. The upper clear liquid was removed, and the lower precipitate was washed three times with a mixed solution of anhydrous toluene and water (volume ratio 1:1), and then transferred to a vacuum drying oven for overnight drying at 60 °C to obtain silica nanoparticles modified with 3-cyano-4-fluorobenzeneboronic acid (MSN-CFPBA).

[0056] The sodium salt NaTFSI, MSN-CFPBA and PEO substrate (n NaTFSI :n PEO = 1:16, m MSN-CFPBA :m PEO = 0.3:10) were successively dissolved in anhydrous acetonitrile and stirred at room temperature for 24 h to obtain a homogeneous solution.

[0057] The homogeneous solution was spin-coated on a polytetrafluoroethylene template and transferred to a vacuum drying oven for drying at 60 °C for 24 h. PEO-3.0% MSN-CFPBA was obtained.

[0058] Comparative Example 1

[0059] Referring to Examples 1-4, a comparative sample of PEO polymer solid electrolyte was prepared without adding MSN-CFPBA additive, that is, a PEO solid electrolyte containing PEO and sodium salt was used as Comparative Example 1. The specific operation was as follows: Sodium salt NaTFSI and PEO substrate (n NaTFSI :n PEO = 1:16) were successively dissolved in anhydrous acetonitrile and stirred at room temperature for 24 h; then the homogeneous solution was scraped onto a polytetrafluoroethylene template and transferred to a vacuum drying oven, dried at 60 °C for 24 h, and the PEO solid electrolyte was obtained.

[0060] After the batteries prepared in Examples 1-4 and Comparative Example 1 were placed in a constant temperature and humidity chamber at 60 °C and allowed to stand for 12 h, charge-discharge cycle tests were carried out on a LAND battery tester. The test conditions were as follows: in the voltage range of 2.0-3.8 V, the rate was 0.05-1 C, the charge-discharge rate test was carried out at 25 °C, and the cycle test was carried out at 0.2 C (0.1 C = 129 mAhg -1 ), charged and discharged for 300 cycles, and the results are shown in Tables 1-2.

[0061] Table 1 Cycle performance of the batteries with solid electrolytes of Examples 1-4 and Comparative Example 1 paired with sodium iron pyrophosphate phosphate

[0062]

[0063] Table 2 Rate performance of the batteries with solid electrolytes of Examples 1-4 and Comparative Example 1 paired with sodium iron pyrophosphate phosphate

[0064]

[0065] Table 3 Ionic conductivity of the solid electrolytes of Example 3 and Comparative Example 1 at different temperatures

[0066] Example 3 Comparative Example 1 30℃ <![CDATA[6.32×10 -5 Scm -1 > <![CDATA[8.80×10 -6 Scm -1 > 40℃ <![CDATA[5.20×10 -4 Scm -1 > <![CDATA[3.25×10 -5 Scm -1 > 50℃ <![CDATA[4.23×10 -4 Scm -1 > <![CDATA[7.69×10 -5 Scm -1 > 60℃ <![CDATA[6.56×10 -4 Scm -1 > <![CDATA[4.51×10 -5 Scm -1 >

[0067] Table 1 shows the cycle performance data of the batteries prepared in Examples 1-4 and Comparative Example 1. According to Table 1, at a current density of 0.2 C, the initial discharge specific capacity of the lithium-ion battery with PEO-2.0% MSN-CFPBA polymer solid electrolyte is 92.35 mAh / g, and the discharge specific capacity after 300 cycles is 90.48 mAh / g, indicating that the battery exhibits excellent initial cycle discharge capacity and cycle stability. Table 2 shows the rate performance data of the batteries prepared in Examples 1-4 and Comparative Example 1, Figures 2-6 is the rate performance diagram of the sodium-ion batteries prepared in Examples 1-4 and Comparative Example 1. According to Table 2 and Figure 4It can be seen that the battery prepared in Example 3 has a higher discharge specific capacity and capacity retention rate. Table 3 shows the ionic conductivity data of the electrolytes in Example 3 and Comparative Example 1 at different temperatures. The test results show that at 60 °C, the ionic conductivity of Example 3 is the highest, and the battery assembled with the PEO-2.0% MSN-CFPBA electrolyte has the best cycle performance and rate performance.

[0068] The above content is a specific description of the content of the present invention in combination with preferred embodiments, but it cannot be determined that the specific implementation of the present invention is only limited to the described embodiments. For those skilled in the art who understand the present invention, without departing from the research idea of the present invention, several evolutions and substitutions can still be made, and these deductions and substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A method for preparing a polymer solid electrolyte, characterized in that: The method is as follows: Step 1: Surface pretreatment of silica: Disperse nano-silica in dilute hydrochloric acid to form a solution with a concentration of 0.1 - 1.0 g / mL, perform ultrasonic treatment to remove surface impurities, wash with deionized water until neutral, dry at 80 - 120 °C for 4 - 10 h, and then calcine at 400 - 600 °C for 1 - 5 h to activate surface hydroxyl groups; Step 2: Ultrasonically disperse the activated nano-silica in anhydrous toluene, then add 3-cyano-4-fluorobenzeneboronic acid (CFBBA), stir and mix evenly, and heat under reflux at 60 - 80 °C for 6 - 16 h; Step 3: After the reaction is completed, cool and centrifuge for 30 min, remove the upper clear liquid, wash the lower precipitate three times with a mixed solution of anhydrous toluene and water (volume ratio 1:1), transfer to a vacuum drying oven and dry overnight at 60 °C to obtain 3-cyano-4-fluorobenzeneboronic acid-modified nano-silica (MSN-CFPBA); Step 4: Dissolve the metal sodium salt, 3-cyano-4-fluorobenzeneboronic acid-modified nano-silica (MSN-CFPBA) and the polymer substrate in a polar solvent in sequence and stir evenly to obtain a homogeneous solution; Step 5: Uniformly scrape the obtained homogeneous solution onto a polytetrafluoroethylene template, transfer to a vacuum drying oven and dry thoroughly to obtain a polymer solid electrolyte.

2. The preparation method of a polymer solid electrolyte according to claim 1, characterized in that: In Step 1, the concentration of the dilute hydrochloric acid is 1 M; the concentration of the solution is 0.2 - 0.6 g / mL, preferably 0.4 g / mL; the drying condition is drying at 100 °C for 6 h; the calcination condition is calcination at 500 °C for 2 h.

3. The preparation method of a polymer solid electrolyte according to claim 1, characterized in that: In Step 2, the mass ratio of the nano-silica to 3-cyano-4-fluorobenzeneboronic acid is 1:2, and the concentration of the reflux solution is 0.05 - 0.2 g / mL.

4. The preparation method of a polymer solid electrolyte according to claim 1, characterized in that: In Step 2, the reflux condition is reflux at 80 °C for 12 h.

5. The preparation method of a polymer solid electrolyte according to claim 1, wherein: In Step 4, the metal sodium salt is one or more of sodium hexafluorophosphate (NaPF4), sodium perchlorate (NaClO4), sodium difluoro(oxalato)borate (NaDFOB), sodium tetrafluoroborate (NaBF4), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), sodium bis(difluoromethanesulfonyl)imide (NaFSI); the material of the polymer substrate is one or more of polyethylene oxide (PEO), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN); the polar solvent is acetonitrile or dimethyl sulfoxide; in the homogeneous solution, the molar ratio of the metal sodium salt to the polymer substrate is 1:16, and the mass ratio of the MSN-CFPBA to the polymer substrate is 0.02 - 1:

10.

6. The preparation method of a polymer solid electrolyte according to claim 1, characterized in that: In Step 5, the drying temperature is 60 °C and the time is 10 - 36 h.

7. A polymer solid electrolyte prepared by the preparation method according to any one of claims 1 - 6.

8. A solid-state battery, characterized in that, The solid-state battery includes the polymer solid electrolyte as described in any one of claims 1 to 6. The solid-state battery includes a sodium negative electrode, a polymer solid electrolyte material, and a positive electrode material. The positive electrode material is at least one of sodium iron phosphate, sodium vanadium phosphate, sodium titanium phosphate, sodium iron sulfate, sodium iron pyrophosphate, sodium ion fluorophosphate, sodium manganese oxide, and sodium vanadium fluorophosphate.

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