A polymer solid-state electrolyte for lithium-ion batteries and a method for preparing the same

Abstract

The application discloses a polymer solid electrolyte for a lithium ion battery and a preparation method thereof, wherein isobornyl methacrylate is 2-7 parts, carbitol acrylate is 2-6 parts, polyethylene glycol monomethyl ether acrylate is 8-10 parts, polyethylene glycol dimethacrylate is 1-3 parts, vinyl ethylene carbonate is 2-7 parts, lithium bis-trifluoromethanesulfonimide is 10-60 parts, butanedinitrile is 7-40 parts, and fluoroethylene carbonate is 1-6 parts. The polymer solid electrolyte has high ion conductivity of 0.73*10 ‑3 S cm ‑1 at room temperature, has a high voltage window of 4.75 V, and has certain fast charging performance and can be stably cycled for 1800 times at a high rate of 5 C, so that the excellent electrochemical performance and the simple synthesis method can meet the requirements of the solid electrolyte.

Description

Technical Field

[0001] This invention relates to the field of secondary battery technology, specifically to a polymer solid electrolyte for lithium-ion batteries and its preparation method. Background Technology

[0002] The commercialization of lithium-ion batteries marks a significant milestone in the development of energy storage technology. Favored for their high energy density, high operating voltage, excellent cycle life, and low self-discharge rate, they now power a wide range of devices, including portable electronic devices, electric vehicles, and large-scale energy storage components. However, traditional liquid lithium-ion batteries present significant safety challenges, such as uncontrollable internal side reactions, safety issues caused by lithium dendrite puncture, and the susceptibility of the liquid electrolyte to leakage and flammability.

[0003] Replacing flammable liquid electrolytes with thermally stable solid electrolytes is considered a fundamental solution to safety issues. Currently, various solid electrolytes have been developed, which can be broadly classified into inorganic solid electrolytes and polymer solid electrolytes. Existing inorganic solid electrolytes mainly include three types: oxides, sulfides, and halides. Oxides such as LLZO have high interfacial impedance and are brittle, sulfides such as LGPS are sensitive to water and oxygen and have high commercialization costs, and halides such as Li3YCl6 have low chemical stability, are prone to side reactions, and have high process difficulty. Polymer solid electrolytes have lower costs and are easier to produce, but existing polymer electrolytes such as PEO, PVDF, and PAN, which are polymers composed of monomers, have disadvantages such as low ionic conductivity, narrow electrochemical window, and the need to operate at high temperatures. Summary of the Invention

[0004] The purpose of this invention is to provide a polymer solid electrolyte for lithium-ion batteries and its preparation method, in order to solve the problems mentioned in the background art, such as the low ionic conductivity, narrow electrochemical window, and the need for high-temperature operation of existing polymer electrolytes composed of monomers such as PEO, PVDF, and PAN.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a polymer solid electrolyte for lithium-ion batteries, comprising the following raw materials in parts by weight: 2-7 parts of isobornyl methacrylate, 2-6 parts of carbityl acrylate, 8-10 parts of polyethylene glycol methyl ether methacrylate, 1-3 parts of polyethylene glycol dimethacrylate, 2-7 parts of ethylene ethylene carbonate, 10-60 parts of lithium bis(trifluoromethanesulfonyl)imide, 7-40 parts of succinic anionyl, and 1-6 parts of fluoroethylene carbonate.

[0006] Preferably, the MEHQ stabilizer content in the isoborneol methacrylate is 50-150 ppm. Preferably, the carbit acrylate is a 90% concentration stabilizer-dispersed carbit acrylate.

[0007] Preferably, the average molecular weight of the polyethylene glycol methyl ether methacrylate is 475.

[0008] Preferably, the polyethylene glycol dimethacrylate has an average molecular weight of 750.

[0009] A preparation method for preparing a polymer solid electrolyte involves magnetically stirring isobornyl methacrylate, carbityl acrylate, polyethylene glycol dimethacrylate, polyethylene glycol methyl ether methacrylate, ethylene ethylene carbonate, succinate, lithium bis(trifluoromethanesulfonyl)imide, and fluoroethylene carbonate in a glove box to obtain a uniform solution, and then adding 1 mg of azobisisobutyronitrile as an initiator.

[0010] Preferably, the water and oxygen content in the glove box is less than 0.1 ppm. The above solution is transferred to a 70°C constant temperature oven and heated for 0.5 h to obtain a polymer solid electrolyte product.

[0011] A preparation method for further preparing a battery using the electrolyte obtained by the above preparation method, the preparation method comprising the following steps: Step 1: Weigh 0.1 g of PVDF and 0.1 g of conductive carbon, add 4 ml of NMP, and stir to disperse; Step 2: Weigh 0.8 g of lithium iron phosphate powder, add it to the dispersion solution, and stir for 24 h to make the slurry uniformly mixed.

[0012] Step 3: The obtained positive electrode slurry is uniformly coated onto copper foil using a small coating machine in the laboratory, and then vacuum dried at 120°C for 12 h in a vacuum drying oven, and then stamped into a circular electrode sheet with a diameter of 13 mm.

[0013] Step 4: Transfer the weighed electrode sheets to the glove box, use the lithium metal sheet as the counter electrode, and add the polymer solid electrolyte to assemble a CR2032 coin cell.

[0014] Preferably, the water and oxygen content in the glove box is less than 0.1 ppm, and the amount of polymer solid electrolyte added is 100 μL.

[0015] Compared with the prior art, the beneficial effects of the present invention are: the polymer solid electrolyte for lithium-ion batteries and its preparation method thereof, the polymer solid electrolyte not only has a strength of 0.73 × 10⁻⁶ at room temperature, but also... -3 S cm -1With its high ionic conductivity, high voltage window of 4.75 V, and certain fast-charging performance, it can stably cycle 1800 times at a high rate of 5 C. These excellent electrochemical properties, combined with a simple synthesis method, can meet the current requirements for solid electrolytes.

[0016] 1. In polymer solid electrolytes, isobornyl methacrylate reduces polymer crystallinity and can adjust viscosity; carbityl acrylate has certain adhesive properties and improves antioxidant properties; polyethylene glycol methyl ether methacrylate can enhance polymer conductivity and increase lithium ion transference number. 2. Polyethylene glycol dimethacrylate (PEG) acts as a crosslinking agent to bind polymer monomers together. Lithium bis(trifluoromethanesulfonyl)imide provides lithium ions and has good conductivity. Ethylene carbonate acts as a thickener to reduce polymer crystallinity. Succinate can improve the electrochemical window. Fluorinated ethylene carbonate acts as an additive to stabilize the electrode and reduce the occurrence of side reactions. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the ionic conductivity of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the cycle number in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the electrochemical window in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the ionic conductivity of Embodiment 2 of the present invention; Figure 5 This is a schematic diagram of the cycle number in Embodiment 2 of the present invention; Figure 6 This is a schematic diagram of the electrochemical window in Embodiment 2 of the present invention; Figure 7 This is a schematic diagram of the ionic conductivity of Embodiment 3 of the present invention; Figure 8 This is a schematic diagram of the cycle number in Embodiment 3 of the present invention; Figure 9 This is a schematic diagram of the electrochemical window in Embodiment 3 of the present invention; Figure 10 This is a schematic diagram of the ionic conductivity of Embodiment 7 of the present invention; Figure 11 This is a schematic diagram of the cycle number in Embodiment Seven of the present invention; Figure 12 This is a schematic diagram of the electrochemical window in Embodiment 7 of the present invention; Figure 13 This is a schematic diagram of the ionic conductivity of Embodiment 8 of the present invention; Figure 14 This is a schematic diagram of the cycle number in Embodiment 8 of the present invention; Figure 15 This is a schematic diagram of the electrochemical window in Embodiment 8 of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please see Figures 1-15 The present invention provides the following technical solution: Example 1: 0.32 g of isobornyl methacrylate, 0.26 g of carbityl acrylate, 0.17 g of polyethylene glycol dimethacrylate, 1.34 g of polyethylene glycol methyl ether methacrylate, 0.32 g of ethylene carbonate, 0.32 g of succinate, 0.48 g of lithium bis(trifluoromethanesulfonyl)imide, and 0.05 g of fluoroethylene carbonate were magnetically stirred in a glove box (water and oxygen content both below 0.1 ppm) until homogeneous; 1 mg of azobisisobutyronitrile was added as an initiator. The above solution was transferred to a 70°C constant temperature oven and heated for 0.5 hours to obtain the polymer solid electrolyte product.

[0020] The specific steps for preparing a lithium-ion battery are as follows: Weigh 0.1 g of PVDF and 0.1 g of conductive carbon, add 4 ml of NMP, and stir to disperse. Weigh 0.8 g of lithium iron phosphate powder, add it to the dispersion solution, and stir for 24 h to ensure the slurry is homogeneous.

[0021] The obtained positive electrode slurry was uniformly coated onto copper foil using a small coating machine in the laboratory, and then vacuum dried at 120°C for 12 h in a vacuum drying oven. It was then stamped into a circular electrode sheet with a diameter of 13 mm.

[0022] After weighing, the electrode sheets were transferred to a glove box (where the water and oxygen content were both below 0.1 ppm). Using a lithium metal sheet as the counter electrode, 100 μL of polymer solid electrolyte was added to assemble a CR2032 coin cell.

[0023] The assembled battery was transferred out of the glove box and placed in a 70°C constant temperature chamber for 0.5 h. Its electrochemical performance was then tested using a charge-discharge tester with a constant current of 200 mA g. -1 The voltage test range is 0.01~5 V.

[0024] like Figure 1 , Figure 2 and Figure 3 As shown, the ionic conductivity of Example 1 is 0.25 × 10⁻⁶. -3 S cm -1 It can cycle 100 times at a rate of 0.5 C, with an electrochemical window of 4.1 V.

[0025] Example 2: 0.2 g of isobornyl methacrylate, 0.18 g of carbityl acrylate, 0.11 g of polyethylene glycol dimethacrylate, 0.89 g of polyethylene glycol methyl ether methacrylate, 0.22 g of ethylene carbonate, 0.64 g of succinic anionyl nitrile, 0.96 g of lithium bis(trifluoromethanesulfonyl)imide, and 0.1 g of fluoroethylene carbonate were magnetically stirred in a glove box (water and oxygen content both below 0.1 ppm); 1 mg of azobisisobutyronitrile was added as an initiator. The above solution was transferred to a 70°C constant temperature oven and heated for 0.5 hours to obtain the polymer solid electrolyte product.

[0026] The specific steps for preparing a lithium-ion battery are as follows: Weigh 0.1 g of PVDF and 0.1 g of conductive carbon, add 4 ml of NMP, and stir to disperse. Weigh 0.8 g of lithium iron phosphate powder, add it to the dispersion solution, and stir for 24 h to ensure the slurry is homogeneous.

[0027] The obtained positive electrode slurry was uniformly coated onto copper foil using a small coating machine in the laboratory, and then vacuum dried at 120°C for 12 h in a vacuum drying oven. It was then stamped into a circular electrode sheet with a diameter of 13 mm.

[0028] After weighing, the electrode sheets were transferred to a glove box (where the water and oxygen content were both below 0.1 ppm). Using a lithium metal sheet as the counter electrode, 100 μL of polymer solid electrolyte was added to assemble a CR2032 coin cell.

[0029] The assembled battery was transferred out of the glove box and placed in a 70°C constant temperature chamber for 0.5 h. Its electrochemical performance was then tested using a charge-discharge tester with a constant current of 200 mA g. -1 The voltage test range is 0.01~5 V.

[0030] like Figure 4 , Figure 5 and Figure 6 As shown, the ionic conductivity of Example 2 is 0.47 × 10⁻⁶. -3 S cm -1 It can cycle 200 times at a rate of 0.5 C, with an electrochemical window of 4.06 V.

[0031] Example 3: 0.11 g of isobornyl methacrylate, 0.08 g of carbityl acrylate, 0.05 g of polyethylene glycol dimethacrylate, 0.45 g of polyethylene glycol methyl ether methacrylate, 0.1 g of ethylene carbonate, 0.96 g of succinic anionyl nitrile, 1.44 g of lithium bis(trifluoromethanesulfonyl)imide, and 0.14 g of fluoroethylene carbonate were magnetically stirred in a glove box (water and oxygen content both below 0.1 ppm) until homogeneous; 1 mg of azobisisobutyronitrile was added as an initiator. The above solution was transferred to a 70°C constant temperature oven and heated for 0.5 hours to obtain the polymer solid electrolyte product.

[0032] The specific steps for preparing a lithium-ion battery are as follows: Weigh 0.1 g of PVDF and 0.1 g of conductive carbon, add 4 ml of NMP, and stir to disperse. Weigh 0.8 g of lithium iron phosphate powder, add it to the dispersion solution, and stir for 24 h to ensure homogeneity.

[0033] The obtained positive electrode slurry was uniformly coated onto copper foil using a small coating machine in the laboratory, and then vacuum dried at 120°C for 12 h in a vacuum drying oven. It was then stamped into a circular electrode sheet with a diameter of 13 mm.

[0034] After weighing, the electrode sheets were transferred to a glove box (where the water and oxygen content were both below 0.1 ppm). Using a lithium metal sheet as the counter electrode, 100 μL of polymer solid electrolyte was added to assemble a CR2032 coin cell.

[0035] The assembled battery was transferred out of the glove box and placed in a 70°C constant temperature chamber for 0.5 h. Its electrochemical performance was then tested using a charge-discharge tester with a constant current of 200 mA g. -1 The voltage test range is 0.01~5 V.

[0036] like Figure 7 , Figure 8 and Figure 9 As shown, the ionic conductivity of Example 3 is 0.49 × 10⁻⁶. -3 S cm -1 It can cycle 400 times at a 0.5 C rate, with an electrochemical window of 4.47 V.

[0037] Example 4: 0.26 g of isobornyl methacrylate, 0.22 g of carbityl acrylate, 0.14 g of polyethylene glycol dimethacrylate, 1.04 g of polyethylene glycol methyl ether methacrylate, 0.24 g of ethylene carbonate, 0.38 g of succinic anionyl nitrile, 0.57 g of lithium bis(trifluoromethanesulfonyl)imide, and 0.06 g of fluoroethylene carbonate were magnetically stirred in a glove box (water and oxygen content both below 0.1 ppm) until homogeneous; 1 mg of azobisisobutyronitrile was added as an initiator. The above solution was transferred to a 70°C constant temperature oven and heated for 0.5 hours to obtain the polymer solid electrolyte product.

[0038] The specific steps for preparing a lithium-ion battery are as follows: Weigh 0.1 g of PVDF and 0.1 g of conductive carbon, add 4 ml of NMP, and stir to disperse. Weigh 0.8 g of lithium iron phosphate powder, add it to the dispersion solution, and stir for 24 h to ensure the slurry is homogeneous.

[0039] The obtained positive electrode slurry was uniformly coated onto copper foil using a small coating machine in the laboratory, and then vacuum dried at 120°C for 12 h in a vacuum drying oven. It was then stamped into a circular electrode sheet with a diameter of 13 mm.

[0040] After weighing, the electrode sheets were transferred to a glove box (where the water and oxygen content were both below 0.1 ppm). Using a lithium metal sheet as the counter electrode, 100 μL of polymer solid electrolyte was added to assemble a CR2032 coin cell.

[0041] The assembled battery was transferred out of the glove box and placed in a 70°C constant temperature chamber for 0.5 h. Its electrochemical performance was then tested using a charge-discharge tester with a constant current of 200 mA g. -1 The voltage test range is 0.01~5 V.

[0042] Example 5: 0.16 g of isobornyl methacrylate, 0.13 g of carbityl acrylate, 0.08 g of polyethylene glycol dimethacrylate, 0.64 g of polyethylene glycol methyl ether methacrylate, 0.17 g of ethylene carbonate, 0.94 g of succinic anionyl nitrile, 1.42 g of lithium bis(trifluoromethanesulfonyl)imide, and 0.14 g of fluoroethylene carbonate were magnetically stirred in a glove box (water and oxygen content both below 0.1 ppm) until homogeneous; 1 mg of azobisisobutyronitrile was added as an initiator. The above solution was transferred to a 70°C constant temperature oven and heated for 0.5 hours to obtain the polymer solid electrolyte product.

[0043] The specific steps for preparing a lithium-ion battery are as follows: Weigh 0.1 g of PVDF and 0.1 g of conductive carbon, add 4 ml of NMP, and stir to disperse. Weigh 0.8 g of lithium iron phosphate powder, add it to the dispersion solution, and stir for 24 h to ensure the slurry is homogeneous.

[0044] The obtained positive electrode slurry was uniformly coated onto copper foil using a small coating machine in the laboratory, and then vacuum dried at 120°C for 12 h in a vacuum drying oven. It was then stamped into a circular electrode sheet with a diameter of 13 mm.

[0045] After weighing, the electrode sheets were transferred to a glove box (where the water and oxygen content were both below 0.1 ppm). Using a lithium metal sheet as the counter electrode, 100 μL of polymer solid electrolyte was added to assemble a CR2032 coin cell.

[0046] The assembled battery was transferred out of the glove box and placed in a 70°C constant temperature chamber for 0.5 h. Its electrochemical performance was then tested using a charge-discharge tester with a constant current of 200 mA g. -1 The voltage test range is 0.01~5 V.

[0047] Example 6: 0.09 g of isobornyl methacrylate, 0.08 g of carbityl acrylate, 0.04 g of polyethylene glycol dimethacrylate, 0.36 g of polyethylene glycol methyl ether methacrylate, 0.09 g of ethylene carbonate, 1.1 g of succinate, 1.58 g of lithium bis(trifluoromethanesulfonyl)imide, and 0.16 g of fluoroethylene carbonate were magnetically stirred in a glove box (water and oxygen content both below 0.1 ppm) until homogeneous; 1 mg of azobisisobutyronitrile was added as an initiator. The above solution was transferred to a 70°C constant temperature oven and heated for 0.5 hours to obtain the polymer solid electrolyte product.

[0048] The specific steps for preparing a lithium-ion battery are as follows: Weigh 0.1 g of PVDF and 0.1 g of conductive carbon, add 4 ml of NMP, and stir to disperse. Weigh 0.8 g of lithium iron phosphate powder, add it to the dispersion solution, and stir for 24 h to ensure the slurry is homogeneous.

[0049] The obtained positive electrode slurry was uniformly coated onto copper foil using a small coating machine in the laboratory, and then vacuum dried at 120°C for 12 h in a vacuum drying oven. It was then stamped into a circular electrode sheet with a diameter of 13 mm.

[0050] After weighing, the electrode sheets were transferred to a glove box (where the water and oxygen content were both below 0.1 ppm). Using a lithium metal sheet as the counter electrode, 100 μL of polymer solid electrolyte was added to assemble a CR2032 coin cell.

[0051] The assembled battery was transferred out of the glove box and placed in a 70°C constant temperature chamber for 0.5 h. Its electrochemical performance was then tested using a charge-discharge tester with a constant current of 200 mA g. -1 The voltage test range is 0.01~5 V.

[0052] Example 7: 0.06 g of isobornyl methacrylate, 0.05 g of carbityl acrylate, 0.03 g of polyethylene glycol dimethacrylate, 0.24 g of polyethylene glycol methyl ether methacrylate, 0.06 g of ethylene carbonate, 0.86 g of succinic anionyl nitrile, 1.28 g of lithium bis(trifluoromethanesulfonyl)imide, and 0.13 g of fluoroethylene carbonate were magnetically stirred in a glove box (water and oxygen content both below 0.1 ppm) until homogeneous; 1 mg of azobisisobutyronitrile was added as an initiator. The above solution was transferred to a 70°C constant temperature oven and heated for 0.5 hours to obtain the polymer solid electrolyte product.

[0053] The specific steps for preparing a lithium-ion battery are as follows: Weigh 0.1 g of PVDF and 0.1 g of conductive carbon, add 4 ml of NMP, and stir to disperse. Weigh 0.8 g of lithium iron phosphate powder, add it to the dispersion solution, and stir for 24 h to ensure the slurry is homogeneous.

[0054] The obtained positive electrode slurry was uniformly coated onto copper foil using a small coating machine in the laboratory, and then vacuum dried at 120°C for 12 h in a vacuum drying oven. It was then stamped into a circular electrode sheet with a diameter of 13 mm.

[0055] After weighing, the electrode sheets were transferred to a glove box (where the water and oxygen content were both below 0.1 ppm). Using a lithium metal sheet as the counter electrode, 100 μL of polymer solid electrolyte was added to assemble a CR2032 coin cell.

[0056] The assembled battery was transferred out of the glove box and placed in a 70°C constant temperature chamber for 0.5 h. Its electrochemical performance was then tested using a charge-discharge tester with a constant current of 200 mA g. -1 The voltage test range is 0.01~5 V.

[0057] like Figure 10 , Figure 11 and Figure 12 As shown, the ionic conductivity of Example 7 is 0.73 × 10⁻⁶. -3 S cm -1 It can cycle 1800 times at a 5 C rate, with an electrochemical window of 4.75 V.

[0058] Example 8: 0.06 g of isobornyl methacrylate, 0.05 g of carbityl acrylate, 0.03 g of polyethylene glycol dimethacrylate, 0.23 g of polyethylene glycol methyl ether methacrylate, 0.05 g of ethylene ethylene carbonate, 1.00 g of succinate, 1.51 g of lithium bis(trifluoromethanesulfonyl)imide, and 0.15 g of fluoroethylene carbonate were magnetically stirred in a glove box (water and oxygen content both below 0.1 ppm) until homogeneous; 1 mg of azobisisobutyronitrile was added as an initiator. The above solution was transferred to a 70°C constant temperature oven and heated for 0.5 hours to obtain the polymer solid electrolyte product.

[0059] The specific steps for preparing a lithium-ion battery are as follows: Weigh 0.1 g of PVDF and 0.1 g of conductive carbon, add 4 ml of NMP, and stir to disperse. Weigh 0.8 g of lithium iron phosphate powder, add it to the dispersion solution, and stir for 24 h to ensure the slurry is homogeneous.

[0060] The obtained positive electrode slurry was uniformly coated onto copper foil using a small coating machine in the laboratory, and then vacuum dried at 120°C for 12 h in a vacuum drying oven. It was then stamped into a circular electrode sheet with a diameter of 13 mm.

[0061] After weighing, the electrode sheets were transferred to a glove box (where the water and oxygen content were both below 0.1 ppm). Using a lithium metal sheet as the counter electrode, 100 μL of polymer solid electrolyte was added to assemble a CR2032 coin cell.

[0062] The assembled battery was transferred out of the glove box and placed in a 70°C constant temperature chamber for 0.5 h. Its electrochemical performance was then tested using a charge-discharge tester with a constant current of 200 mA g. -1 The voltage test range is 0.01~5 V.

[0063] Example 9: 0.05 g of isobornyl methacrylate, 0.04 g of carbityl acrylate, 0.03 g of polyethylene glycol dimethacrylate, 0.22 g of polyethylene glycol methyl ether methacrylate, 0.05 g of ethylene carbonate, 1.12 g of succinate, 1.68 g of lithium bis(trifluoromethanesulfonyl)imide, and 0.17 g of fluoroethylene carbonate were magnetically stirred in a glove box (water and oxygen content both below 0.1 ppm) until homogeneous; 1 mg of azobisisobutyronitrile was added as an initiator. The above solution was transferred to a 70°C constant temperature oven and heated for 0.5 hours to obtain the polymer solid electrolyte product.

[0064] The specific steps for preparing a lithium-ion battery are as follows: Weigh 0.1 g of PVDF and 0.1 g of conductive carbon, add 4 ml of NMP, and stir to disperse. Weigh 0.8 g of lithium iron phosphate powder, add it to the dispersion solution, and stir for 24 h to ensure the slurry is homogeneous.

[0065] The obtained positive electrode slurry was uniformly coated onto copper foil using a small coating machine in the laboratory, and then vacuum dried at 120°C for 12 h in a vacuum drying oven. It was then stamped into a circular electrode sheet with a diameter of 13 mm.

[0066] After weighing, the electrode sheets were transferred to a glove box (where the water and oxygen content were both below 0.1 ppm). Using a lithium metal sheet as the counter electrode, 100 μL of polymer solid electrolyte was added to assemble a CR2032 coin cell.

[0067] like Figure 13 , Figure 14 and Figure 15 As shown, the ionic conductivity of Example 9 is 0.72 × 10⁻⁶. -3 S cm -1 It can cycle 400 times at a 0.5C rate, with an electrochemical window of 4.74 V.

[0068] Meanwhile, the button batteries obtained in the above embodiments were all tested for ionic conductivity according to national standard GB / T 11007-2008, and their voltage window was measured according to national standard GB / T38894-2020. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A polymer solid electrolyte for lithium-ion batteries, characterized in that: The raw materials include the following parts by weight: 2-7 parts isobornyl methacrylate, 2-6 parts carbityl acrylate, 8-10 parts polyethylene glycol methyl ether methacrylate, 1-3 parts polyethylene glycol dimethacrylate, 2-7 parts ethylene ethylene carbonate, 10-60 parts lithium bis(trifluoromethanesulfonyl)imide, 7-40 parts succinic anionyl, and 1-6 parts fluoroethylene carbonate.

2. The electrolyte according to claim 1, characterized in that: The content of MEHQ stabilizer in the isoborneol methacrylate is 50-150 ppm.

3. The electrolyte according to claim 1, characterized in that: The average molecular weight of the polyethylene glycol methyl ether methacrylate is 475.

4. The electrolyte according to claim 1, characterized in that: The average molecular weight of the polyethylene glycol dimethacrylate is 750.

5. A preparation method for preparing the polymer solid electrolyte of any one of claims 1-4, characterized in that: Isoborneol methacrylate, carbityl acrylate, polyethylene glycol dimethacrylate, polyethylene glycol methyl ether methacrylate, ethylene ethylene carbonate, succinate, lithium bis(trifluoromethanesulfonyl)imide, and fluoroethylene carbonate were magnetically stirred in a glove box to obtain a solution, and 1 mg of azobisisobutyronitrile was added as an initiator.

6. The preparation method according to claim 5, characterized in that: The water and oxygen content in the glove box was both below 0.1 ppm. The above solution was transferred to a 70°C constant temperature oven and heated for 0.5 h to obtain a polymer solid electrolyte product.

7. A preparation method, characterized in that: The preparation method includes the following steps: Step 1: Weigh 0.1 g of PVDF and 0.1 g of conductive carbon, add 4 ml of NMP, and stir to disperse; Step 2: Weigh 0.8 g of lithium iron phosphate powder, add it to the dispersion solution, and stir for 24 h to ensure the slurry is evenly mixed; Step 3: The obtained positive electrode slurry is uniformly coated onto copper foil using a small coating machine in the laboratory, and then vacuum dried at 120 °C for 12 h in a vacuum drying oven, and then stamped into a circular electrode sheet with a diameter of 13 mm. Step 4: Transfer the weighed electrode sheets to the glove box, use the lithium metal sheet as the counter electrode, and add the polymer solid electrolyte to assemble a CR2032 coin cell.

8. The preparation method according to claim 7, characterized in that: The water and oxygen content in the glove box is less than 0.1 ppm, and the amount of polymer solid electrolyte added is 10-100 μL.

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