Single ion conductor polymer electrolyte and preparation method thereof

Abstract

The invention relates to a single-ion conductor polymer electrolyte and a preparation method thereof, the single-ion conductor polymer electrolyte comprises a structural unit as shown in the following formula: # imgabs0 #, R1, R2, R3, R4, R5, R6, R7 and R8 are respectively and independently selected from H or-SO2N-(Li < + >) SO2CF3, and at least one group in R1, R2, R3, R4, R5, R6, R7 and R8 is-SO2N-(Li < + >) SO2CF3. The lithium ion transference number of the polymer electrolyte can reach 0.89, and the polymer electrolyte has single ion conductor characteristics and excellent ionic conductivity in a solid state, and the ionic conductivity can reach 1.12 * 10 <-4 > S / cm.

Description

Technical Field

[0001] The invention relates to the technical field of solid electrolytes, and in particular to a single ion conductor polymer electrolyte and a preparation method thereof. Background Art

[0002] Lithium-ion batteries are widely used in portable electronic devices, electric vehicles and other fields due to their high energy density and long cycle life. Traditional lithium-ion batteries use liquid electrolytes, which have problems such as flammability, limited operating temperature range, and strong reactivity with electrodes. To address these problems, solid polymer electrolytes (SPE) have received widespread attention as a solvent-free alternative.

[0003] Solid polymer electrolyte is a composite material based on polymer matrix and lithium salt, which realizes the transmission of lithium ions through the movement of polymer chain segments and the dissociation of lithium salt. Its basic structure usually includes polymer matrix (such as polyethylene oxide, PEO) and lithium salt (such as lithium hexafluorophosphate, LiPF 6 ). Polymer electrolytes are considered to be one of the most promising electrolyte materials in solid-state batteries due to their good flexibility, processing performance and excellent interface contact with electrode materials. In polymer electrolytes, the lithium ion transfer number (tLi + ) directly affects the performance and efficiency of the battery. A higher lithium ion transference number means that lithium ions encounter less resistance during transmission and less energy loss, which can significantly improve the battery's charge and discharge efficiency, rate performance, and cycle stability. However, in existing polymer electrolyte systems, the lithium ion transference number is usually low (t Li + <0.5), which is mainly due to the strong interaction between lithium ions and anions during the movement of polymer segments and the dissociation of lithium salts, leading to the formation of ion pairs. The presence of ion pairs not only reduces the effective migration number of lithium ions, but also increases the resistance of ion transmission, which leads to battery energy loss and reduced efficiency.

[0004] Therefore, increasing the number of lithium ion migration in polymer electrolytes and reducing the ion pair phenomenon have become the focus of current research. Summary of the invention

[0005] The object of the present invention is to provide a single ion conductor polymer electrolyte.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned single ion conductor polymer electrolyte.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] In one aspect, the present invention provides a single ion conductor polymer electrolyte, wherein the single ion conductor polymer electrolyte comprises a structural unit as shown in the following formula:

[0009]

[0010] Among them, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 are independently selected from H or -SO 2 N - (Li + )SO 2 CF 3 (lithium perfluorosulfonyl imide), the R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 At least one of the groups is -SO 2 N - (Li + )SO 2 CF 3 .

[0011] The polymer electrolyte of the present invention has a perfluorosulfonyl imide lithium side chain, an ether bond, and an oxadiazole ring in its molecular structure. The synergistic effect of these functional groups significantly promotes the migration of lithium ions, increases the lithium ion migration number, and reduces the formation of ion pairs, thereby improving the overall performance of the polymer electrolyte. The lithium ion migration number of the polymer electrolyte of the present invention can reach 0.89, and it has the characteristics of a single ion conductor. At the same time, it has excellent ionic conductivity in a solid state, and the ionic conductivity can reach 1.12×10 -4 S / cm.

[0012] Preferably, the R 2 , R 7 For-SO 2 N - (Li + )SO 2 CF 3 , the R 1 , R 3 , R 4 , R 5 , R 6 , R 8 are independently selected from H or -SO2 N - (Li + )SO 2 CF 3 ; or, said R 4 , R 5 For-SO 2 N - (Li + )SO 2 CF 3 , the R 1 , R 2 , R 3 , R 6 , R 7 , R 8 are independently selected from H or -SO 2 N - (Li + )SO 2 CF 3 .

[0013] Another aspect of the present invention is to provide a method for preparing the above-mentioned single ion conductor polymer electrolyte, the preparation method comprising the following steps:

[0014] (1) dissolving 4,4'-biphenyl ether dicarboxylic acid and hydrazine sulfate in fuming sulfuric acid, heating and performing copolymerization reaction to obtain a first polymer matrix;

[0015] (2) subjecting the first polymer matrix and phosphorus oxychloride to an acyl chlorination reaction in the presence of an organic solvent to obtain a second polymer matrix;

[0016] (3) subjecting the second polymer matrix, a nucleophilic agent, a base and a catalyst to an amidation reaction in the presence of an organic solvent to obtain a third polymer matrix;

[0017] (4) Mixing the third polymer matrix with lithium hydroxide to obtain the single ion conductor polymer electrolyte.

[0018] The preparation method of the invention is simple, easy to operate, low in cost and suitable for mass production.

[0019] Preferably, the mass ratio of the first polymer matrix to the phosphorus oxychloride is 1:(2-4), more preferably 1:(2.5-3.5), for example 1:2.5, 1:2.8, 1:3, 1:3.3, 1:3.5.

[0020] Preferably, the acyl chlorination reaction temperature is 80-120°C, more preferably 90-110°C, for example 90°C, 95°C, 100°C, 105°C, 110°C.

[0021] More preferably, the acyl chlorination reaction time is 10 to 14 h, more preferably 11 to 13 h, for example 11 h, 11.5 h, 12 h, 12.5 h, 13 h.

[0022] Preferably, the organic solvent in step (2) is nitrogen-methylpyrrolidone.

[0023] Preferably, the nucleophile is trifluoromethanesulfonamide.

[0024] Further preferably, the feed mass ratio of the second polymer matrix to the nucleophilic reagent is 1:(0.8-1.2), for example, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2.

[0025] Preferably, the base is triethylamine.

[0026] Further preferably, the mass volume ratio of the second polymer matrix to the base is 1 g: (2-3) mL, for example, 1 g: 2 mL, 1 g: 2.3 mL, 1 g: 2.5 mL, 1 g: 2.8 mL, 1 g: 3 mL.

[0027] Preferably, the catalyst is 4-dimethylaminopyridine.

[0028] Further preferably, the feed mass volume ratio of the second polymer matrix to the catalyst is 1 g: (0.25-0.45) mL, for example, 1 g: 0.25 mL, 1 g: 0.3 mL, 1 g: 0.35 mL, 1 g: 0.4 mL, 1 g: 0.45 mL.

[0029] Preferably, the temperature of the amidation reaction is -5 to 5°C.

[0030] More preferably, the amidation reaction time is 10 to 14 h, for example, 10 h, 11 h, 12 h, 13 h, or 14 h.

[0031] Preferably, the organic solvent in step (3) is nitrogen-methylpyrrolidone.

[0032] Preferably, the feed mass ratio of the third polymer matrix to the lithium hydroxide is 1:(0.3-1), and more preferably 1:(0.4-0.6).

[0033] Preferably, the molar ratio of the 4,4'-biphenyl ether dicarboxylic acid to the hydrazine sulfate is 1:(0.9-1.1), and more preferably 1:(1-1.1).

[0034] Preferably, the copolymerization reaction temperature is 110-130° C., and the reaction time is 3-5 h.

[0035] More preferably, the copolymerization reaction temperature is 115-125° C., and the reaction time is 3.5-4.5 h.

[0036] Preferably, the temperature of the fuming sulfuric acid is controlled to be 70-80° C. to dissolve the 4,4′-biphenyl ether dicarboxylic acid and the hydrazine sulfate.

[0037] Preferably, the step (1) further comprises washing the reaction product with water, washing with alkali and drying the reaction product after the reaction is completed.

[0038] In some embodiments, the water washing comprises pouring the reaction product into deionized water for washing.

[0039] In some embodiments, the alkaline washing includes neutralizing residual sulfuric acid in the reaction product using lithium hydroxide.

[0040] Preferably, the step (2) further comprises, after the acyl chlorination reaction is completed, washing the reaction system with ice water and drying to obtain the second polymer matrix.

[0041] Preferably, the step (3) specifically includes dissolving the second polymer matrix in the organic solvent to prepare a first solution with a mass fraction of 1 to 10%, dissolving the nucleophilic reagent, base and catalyst in the organic solvent to prepare a second solution with a mass fraction of 5 to 15% and maintaining the solution at -5 to 5°C, mixing the first solution and the second solution for reaction, and after the reaction is completed, washing and drying the reaction product to obtain the third polymer matrix.

[0042] Preferably, the step (4) specifically comprises immersing the third polymer matrix in the aqueous solution of lithium hydroxide to carry out a neutralization reaction, and after the reaction is completed, washing excess alkali solution with deionized water to obtain the single ion conductor polymer electrolyte.

[0043] Preferably, the preparation method further comprises dissolving the single ion conductor polymer electrolyte obtained in step (4) in an organic solvent to prepare a mixed solution, then adding lithium salt to the mixed solution, coating it on a coating machine to form a film after it is evenly dissolved, and drying to obtain the polymer electrolyte.

[0044] In some embodiments, the lithium salt is selected from one or more of lithium bis(trifluoromethylsulfonyl)imide and lithium bis(fluorosulfonyl)imide.

[0045] Further preferably, the feed mass ratio of the single ion conductor polymer electrolyte to the lithium salt is 1:(0.5-1.5), for example, 1:0.5, 1:0.8, 1:1, 1:1.3, 1:1.5.

[0046] In some implementations, the mass concentration of the mixed solution is 5-15%.

[0047] More preferably, the organic solvent used in the mixed solution is nitrogen-methylpyrrolidone.

[0048] The present invention also provides an application of the above-mentioned single-ion conductor polymer electrolyte, which includes using the single-ion conductor polymer electrolyte in a solid-state lithium-ion battery, an electric vehicle battery or a portable electronic device battery.

[0049] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0050] The polymer electrolyte of the present invention has a lithium ion transfer number of up to 0.89, has the characteristics of a single ion conductor, and has excellent ionic conductivity in a solid state, with an ionic conductivity of up to 1.12×10 -4 S / cm.

[0051] The preparation method of the invention is simple, easy to operate, low in cost and suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 is a reaction route diagram of the polymer solid electrolyte involved in Example 1 of the present invention;

[0053] Figure 2 This is the XPS spectrum of the polymer solid electrolyte (before mixing with lithium salt) involved in Example 1 of the present invention;

[0054] Figure 3 The EIS spectra of the polymer solid electrolyte involved in Example 1 of the present invention at different temperatures;

[0055] Figure 4 Schematic diagram of lithium ion activation energy of the polymer solid electrolyte involved in Example 1 of the present invention;

[0056] Figure 5 It curve diagram of the polymer solid electrolyte involved in Example 1 of the present invention and EIS spectra before and after polarization;

[0057] Figure 6 This is a constant current cycle diagram of the Li||Li symmetric battery of the polymer solid electrolyte involved in Example 1 of the present invention. DETAILED DESCRIPTION

[0058] The present invention is further described below in conjunction with the examples. However, the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to the different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0059] Unless otherwise specified, the reagents and instruments mentioned below are all commercially available products or can be prepared by referring to the existing technical methods.

[0060] Hereinafter, the amount of the reaction solvent fuming sulfuric acid used is preferably 600-800% of the total mass of the reaction raw materials (4,4'-biphenyl ether dicarboxylic acid and hydrazine sulfate), or refer to the prior art, without particular limitation.

[0061] Example 1

[0062] Synthesis of polymer solid electrolytes:

[0063] 4,4'-Biphenyl ether dicarboxylic acid and hydrazine sulfate were mixed in a molar ratio of 1:1.05, added into fuming sulfuric acid and heated to 75°C for stirring and dissolution, then heated to 120°C for copolymerization. After reacting for 4 hours, the product was poured into deionized water for washing, and lithium hydroxide was added for soaking to neutralize the residual sulfuric acid in the polymer. Finally, it was washed to neutrality and dried to obtain sulfonated polybiphenyl ether (S-POD).

[0064] Take 5g of the above S-POD and dissolve it in nitrogen methyl pyrrolidone to prepare a 5% mass fraction solution I, add 15g of phosphorus oxychloride, react under heating and stirring at 100°C for 12 hours, pour de-iced water to solidify and wash away the residual monomers, and then dry to obtain sulfonyl chloride polybiphenyl ether (SCl-POD).

[0065] Take 4.63g of the above SCl-POD and dissolve it in N-methylpyrrolidone to prepare 5% mass fraction of solution II. Add 4.34g of trifluoromethanesulfonamide (CF 3 SO 2 NH 2 ), 12.2 mL triethylamine (Et 3 N), 1.65mL of 4-dimethylaminopyridine (DMAP, as a catalyst) was dissolved in nitrogen methyl pyrrolidone, and a 10% mass fraction of solution III was prepared. The solution III was placed in an ice water bath to keep the solution III at 0°C, and the solution II was slowly poured into the solution III, and vigorously stirred for 12 hours. The product was poured into water to wash away the excess monomer and catalyst, and 2.32g of lithium hydroxide was added to neutralize it. Finally, deionized water was used to wash away the excess alkali solution to obtain sulfonyl (trifluoromethylsulfonyl) imide polybiphenyl ether (STFSI-POD), and the solid STFSI-POD was obtained by drying in an oven at 100°C. For the reaction equation, see Figure 1 , where n is selected from an integer of 200 to 400. The XPS spectra of STFSI-POD and S-POD were tested, and it was found that the new CF group absorption peak was successfully grafted to the polymer side chain, and the structure of the polymer itself was retained, proving the success of the grafting.

[0066] The solid STFSI-POD was dissolved in nitrogen methyl pyrrolidone to prepare a 10% mass fraction of solution IV, and lithium bistrifluoromethylsulfonyl imide (LiTFSI) was added in an amount of 10% of the total mass of solution IV. After being uniformly dissolved, the solution was coated on a coating machine to form a film, and dried in an oven to obtain a polymer solid electrolyte.

[0067] Comparative Example 1

[0068] 4,4'-Biphenyl ether dicarboxylic acid and hydrazine sulfate were mixed in a molar ratio of 1:1.05, added into fuming sulfuric acid and heated to 75°C for stirring and dissolution, then heated to 120°C for copolymerization. After reacting for 4 hours, the product was poured into deionized water for washing, and lithium hydroxide was added for soaking to neutralize the residual sulfuric acid in the polymer. Finally, it was washed to neutrality and dried to obtain sulfonated polybiphenyl ether (S-POD).

[0069] The S-POD was dissolved in nitrogen methyl pyrrolidone to prepare a 10% mass fraction solution, and lithium salt LiTFSI was added in an amount of 10% of the total mass of the solution. After being uniformly dissolved, the solution was coated on a coating machine to form a film, and then dried in an oven to obtain a polymer solid electrolyte.

[0070] Comparative Example 2

[0071] 4,4'-biphenyldicarboxylic acid and hydrazine sulfate were mixed in a molar ratio of 1:1.05, added into fuming sulfuric acid and heated to 75°C with stirring to dissolve, then heated to 120°C for copolymerization, and after reacting for 4 hours, the product was poured into deionized water for washing, and lithium hydroxide was added for soaking to neutralize the residual sulfuric acid in the polymer, and finally washed to neutrality and dried to obtain sulfonated polybiphenyl (S-BPOD).

[0072] During the subsequent chlorination, it was found that the polymer (S-BPOD) could not be dissolved in nitrogen-methylpyrrolidone and other conventional organic solvents because the molecular chain was too rigid to perform subsequent modification operations.

[0073] Comparative Example 3

[0074] Mix 4,4'-biphenyl ether dicarboxylic acid, terephthalic acid and hydrazine sulfate in a molar ratio of 5:5:10.05, add into fuming sulfuric acid and heat to 75°C with stirring to dissolve, then heat to 120°C for copolymerization, react for 4 hours, pour the product into deionized water for washing, add lithium hydroxide to soak and neutralize the residual sulfuric acid in the polymer, finally wash to neutrality and dry to obtain comparison sample 3.

[0075] The comparative sample 3 was dissolved in nitrogen methyl pyrrolidone to prepare a 10% mass fraction solution, and lithium salt LiTFSI was added in an amount of 10% of the total mass of the solution. After being uniformly dissolved, the solution was coated on a coating machine to form a film, and then dried in an oven to obtain a polymer solid electrolyte.

[0076] Comparative Example 4

[0077] 4,4'-biphenyl ether dicarboxylic acid, terephthalic acid and hydrazine sulfate were mixed in a molar ratio of 5:5:10.05, added into fuming sulfuric acid and heated to 75°C for stirring and dissolution, then heated to 120°C for copolymerization, and after reacting for 4 hours, the product was poured into deionized water for washing, and lithium hydroxide was added for soaking to neutralize the residual sulfuric acid in the polymer, and finally washed to neutrality and dried to obtain sulfonated polyoxadiazole.

[0078] 5 g of the above sulfonated polyoxadiazole was dissolved in nitrogen methyl pyrrolidone to prepare a 5% mass fraction solution I, 15 g of phosphorus oxychloride was added, and the mixture was heated and stirred at 100° C. for 12 hours. After being solidified by pouring de-iced water and washing away the residual monomers, the mixture was dried to obtain the sulfonyl chloride polyoxadiazole.

[0079] Take 4.63g of the above sulfonyl chloride polyoxadiazole and dissolve it in nitrogen methyl pyrrolidone to prepare 5% mass fraction of solution II. Add 4.34g of trifluoromethanesulfonamide (CF 3 SO 2 NH 2 ), 12.2 mL triethylamine (Et 3 N), 1.65 mL of 4-dimethylaminopyridine (DMAP, as a catalyst) was dissolved in nitrogen-methylpyrrolidone to prepare a 10% mass fraction of solution III, which was placed in an ice water bath to keep solution III at 0°C, solution II was slowly poured into solution III, and vigorously stirred for 12 hours. The product was poured into water to wash away excess monomers and catalysts, and neutralized with lithium hydroxide to obtain a comparative sample 4, which was dried in an oven at 100°C to obtain a solid.

[0080] The solid was dissolved in nitrogen methyl pyrrolidone to prepare a 10% mass fraction solution, and lithium salt LiTFSI was added in an amount of 10% of the total mass of the solution. After being uniformly dissolved, the solution was coated on a coating machine to form a film, and then dried in an oven to obtain a polymer solid electrolyte.

[0081] Performance Testing:

[0082] The polymer solid electrolytes in the above embodiments and comparative examples were placed between stainless steel sheets to assemble batteries, and the EIS spectra at different temperatures were tested (test conditions: voltage amplitude 10 mV, frequency range 100 kHz to 1 Hz, temperature range 10°C to 70°C, heating step 10°C). Figure 3 As shown. According to calculation, the lithium ion conductivity of the polymer solid electrolyte of Example 1 at 30°C is 1.12×10 -4 S cm -1 , the lithium ion activation energy is 0.12 eV; while the lithium ion conductivity of the polymer solid electrolyte of Comparative Example 1 at 30 ° C is 6.98×10 -5 S cm -1The lithium ion conductivity of the solid electrolyte of Comparative Example 3 at 30°C is 1.66×10 -5 S cm -1 The lithium ion conductivity of the solid electrolyte of Comparative Example 4 at 30°C is 5.12×10 -5 Scm -1 , which are lower than those in Example 1. This is because the introduction of the p-benzene structure increases the rigidity of the chain segment, weakens the chain segment transport capacity, and the p-benzene structure cannot be sulfonated, thereby reducing the sulfonic acid group content, resulting in a decrease in ion transport capacity. It can be seen that the rich sulfonic acid groups, ether bonds and fluorine structures of the polymer solid electrolyte of the present invention significantly enhance the lithium ion transport capacity.

[0083] The polymer solid electrolyte in the above embodiment and comparative example was placed between two lithium sheets to assemble a button battery, and a bias voltage of 0.01 V was applied to test the it curve and the EIS spectrum before and after polarization (test conditions: first, the initial resistance (R 0 ). Then, a small DC voltage (ΔV = 0.01 V) was applied to the battery until the current polarization reached equilibrium, and the initial current (I 0 ) and the balancing current (Is), such as Figure 5 As shown. After calculation, the lithium ion migration number of the polymer solid electrolyte of Example 1 is 0.89, while the lithium ion migration number of the polymer solid electrolyte of Comparative Example 1 is 0.62, the lithium ion migration number of the polymer solid electrolyte of Comparative Example 3 is 0.45, and the lithium ion migration number of the polymer solid electrolyte of Comparative Example 4 is 0.66, all of which are lower than that of Example 1. It can be seen that the polymer solid electrolyte of the present invention can effectively reduce the polarization phenomenon of the battery.

[0084] The polymer solid electrolyte in the above embodiment was subjected to constant current cycling (1 mA cm -2 ; 1mA hcm -2 ) test, such as Figure 6 As shown. It can be seen that the rich CF and SO in the polymer solid electrolyte of the present invention 3 - The functional groups form a strong interaction with Li+ at the interface, which not only promotes the uniform distribution of Li+ flux and the effective regulation of lithium nucleation, but also significantly enhances the interface stability, ultimately achieving uniform lithium deposition.

[0085] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A single ion conductor polymer electrolyte, characterized in that: The single ion conductor polymer electrolyte comprises a structural unit as shown in the following formula: Wherein, R1, R2, R3, R4, R5, R6, R7, R8 are independently selected from H or -SO2N - (Li + )SO2CF3, at least one of the R1, R2, R3, R4, R5, R6, R7, and R8 groups is -SO2N - (Li + )SO2CF3.

2. The single ion conductor polymer electrolyte according to claim 1, characterized in that R2 and R7 are -SO2N - (Li + )SO2CF3, wherein R1, R3, R4, R5, R6, and R8 are independently selected from H or -SO2N - (Li + )SO2CF3; or, said R4, R5 are -SO2N - (Li + )SO2CF3, wherein R1, R2, R3, R6, R7, and R8 are independently selected from H or -SO2N - (Li + )SO2CF3.

3. The method for preparing a single ion conductor polymer electrolyte according to claim 1 or 2, characterized in that: The preparation method comprises the following steps: (1) dissolving 4,4'-biphenyl ether dicarboxylic acid and hydrazine sulfate in fuming sulfuric acid, heating and performing copolymerization reaction to obtain a first polymer matrix; (2) subjecting the first polymer matrix and phosphorus oxychloride to an acyl chlorination reaction in the presence of an organic solvent to obtain a second polymer matrix; (3) subjecting the second polymer matrix, a nucleophilic agent, a base and a catalyst to an amidation reaction in the presence of an organic solvent to obtain a third polymer matrix; (4) Mixing the third polymer matrix with lithium hydroxide to obtain the single ion conductor polymer electrolyte.

4. The method for preparing a single ion conductor polymer electrolyte according to claim 3, characterized in that: The mass ratio of the first polymer matrix to the phosphorus oxychloride is 1:(2-4); and / or, The acyl chlorination reaction temperature is 80-120°C; and / or, The organic solvent in step (2) is nitrogen-methyl pyrrolidone.

5. The method for preparing a single ion conductor polymer electrolyte according to claim 3, characterized in that: The nucleophilic agent is trifluoromethanesulfonamide, and the mass ratio of the second polymer matrix to the nucleophilic agent is 1:(0.8-1.2); and / or, The base is triethylamine, and the feed mass volume ratio of the second polymer matrix to the base is 1 g: (2-3) mL; and / or, The catalyst is 4-dimethylaminopyridine, and the feed mass volume ratio of the second polymer matrix to the catalyst is 1 g: (0.25-0.45) mL.

6. The method for preparing a single ion conductor polymer electrolyte according to claim 3 or 5, characterized in that: The temperature of the amidation reaction is -5 to 5°C; and / or, The organic solvent in step (3) is nitrogen-methyl pyrrolidone.

7. The method for preparing a single ion conductor polymer electrolyte according to claim 3, characterized in that: The feed mass ratio of the third polymer matrix to the lithium hydroxide is 1:(0.3-1).

8. The method for preparing a single ion conductor polymer electrolyte according to claim 3, characterized in that: The molar ratio of the 4,4'-biphenyl ether dicarboxylic acid to the hydrazine sulfate is 1:(0.9-1.1); and / or, The copolymerization reaction temperature is 110-130° C., and the reaction time is 3-5 hours.

9. The method for preparing a single ion conductor polymer electrolyte according to claim 3, characterized in that: The step (2) further comprises, after the acyl chlorination reaction is completed, washing the reaction system with ice water and drying to obtain the second polymer matrix; and / or, The step (3) specifically comprises dissolving the second polymer matrix in the organic solvent to prepare a first solution with a mass fraction of 1 to 10%, dissolving the nucleophilic reagent, base and catalyst in the organic solvent to prepare a second solution with a mass fraction of 5 to 15% and maintaining the solution at -5 to 5°C, mixing the first solution and the second solution to react, and washing and drying the reaction product after the reaction to obtain the third polymer matrix; and / or, The step (4) specifically includes immersing the third polymer matrix in the aqueous solution of lithium hydroxide to carry out a neutralization reaction, and after the reaction is completed, washing excess alkali solution with deionized water to obtain the single ion conductor polymer electrolyte.

10. The method for preparing a single ion conductor polymer electrolyte according to claim 3, characterized in that: The preparation method further comprises dissolving the single ion conductor polymer electrolyte obtained in step (4) in an organic solvent to prepare a mixed solution, then adding lithium salt to the mixed solution, coating the mixed solution on a coating machine to form a film after the solution is uniformly dissolved, and drying to obtain the polymer electrolyte.

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