Quasi-solid polymer electrolyte, and preparation method and application thereof
By using polyfluorinated ethylene oxide derivatives and crosslinking agents to form a quasi-solid polymer electrolyte in situ, the safety hazards and performance bottlenecks of traditional lithium batteries have been solved, and a lithium metal battery with high energy density and long life has been achieved.
Patent Information
- Application Number
- CN202511767401.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-27
- Publication Date
- 2026-02-27
AI Technical Summary
Traditional lithium-ion batteries use organic liquid electrolytes, which pose safety risks. Polymer electrolytes have low ionic conductivity, poor interfacial compatibility, and require complex manufacturing processes that consume large amounts of organic solvents, thus affecting battery performance and energy density.
A polymer monomer solution is formed by stirring polyfluoroethylene oxide derivatives and crosslinking agents in an argon atmosphere, and then lithium salt and aluminum trifluoromethanesulfonate are added to form a quasi-solid polymer electrolyte through in-situ polymerization, which improves interfacial compatibility and mechanical strength and reduces interfacial impedance.
It enhances the high-pressure stability and interfacial stability of the electrolyte, improves the energy density and cycle life of the battery, simplifies the manufacturing process, reduces the use of organic solvents, and improves the overall performance of the battery.
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Figure CN121584016A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of electrolytes, and particularly relates to a preparation method of a quasi-solid-state polymer electrolyte based on a polyfluoro-oxirane and application thereof. BACKGROUND
[0002] Lithium-ion batteries are widely used in many technological products due to their excellent performance and portability, and provide strong support for the light and thin design of smart phones, mobile office of notebook computers and fast charging of electric vehicles. However, the traditional graphite negative electrode is unable to bear the burden due to the limitation of the theoretical capacity. Lithium metal has an ultra-high theoretical specific capacity of 3860 mAh / g, and is expected to become a leading candidate for the negative electrode material of high-energy-density batteries in the future. The high volumetric energy density of lithium metal can significantly improve the overall energy of the battery, meeting the demand for long endurance and fast charging of large equipment such as electric vehicles.
[0003] The organic liquid electrolyte of the traditional secondary lithium battery has many safety hazards, such as leakage, flammability and explosion. The solid polymer electrolyte not only avoids these problems, but also exhibits good flexibility. However, the polymer electrolyte in the current polymer lithium secondary battery faces many bottlenecks: the ionic conductivity is low, which is difficult to meet the demand for efficient operation of the battery; the preparation steps of the non-in-situ polymerization process such as casting method are complicated, and a large amount of organic solvent is consumed, which is neither environmentally friendly nor economical; the interface compatibility between the electrolyte and the electrode is poor, resulting in large interface impedance and affecting the performance of the battery; the thickness of the electrolyte is relatively thick, which limits the energy density and volume efficiency of the battery.
[0004] Therefore, there is an urgent need for a new electrolyte in this field. Such an electrolyte needs to have good compatibility with the secondary battery interface, reduce the interface impedance, and improve the overall performance of the battery. At the same time, it should have excellent mechanical strength to ensure the stability and safety of the battery under various working conditions. In addition, good high-pressure resistance is also essential, which will help to improve the voltage window of the battery, thereby further improving the energy density of the battery. In summary, the development of such an electrolyte is of great significance for promoting the development of lithium metal battery technology and meeting the demand for high-performance batteries in modern society. SUMMARY
[0005] In view of the above problems, in a first aspect, the application provides a preparation method of a quasi-solid-state polymer electrolyte, comprising: (1) Dissolve 1,3-dioxolane in a mixed solution of fluoroethylene carbonate and a polyfluoro-oxirane derivative in an argon atmosphere, and then add a crosslinking agent after stirring to obtain a polymer monomer solution; (2) Dissolve lithium bis-trifluoromethylsulfonylimide in the monomer solution to obtain a lithium salt solution; (3) dissolving aluminum triflate into the lithium salt solution, mixing uniformly to obtain a precursor solution, and in-situ polymerizing the precursor solution to obtain a quasi-solid-state polymer electrolyte.
[0006] In some embodiments, in step (1), the polyfluorooxirane derivative is selected from at least one of pentafluoropropyl oxirane, heptafluorobutyl oxirane and nonafluoropentyl oxirane.
[0007] In some embodiments, in step (1), the crosslinking agent is 2,2'-(2,2,3,4,4,5,5-octafluorohexane-1,6-diyl)bis(oxirane) (OFBO).
[0008] In some embodiments, in step (1), the 1,3-dioxolane and the polyfluorooxirane derivative are polymer monomers, and the molar ratio of the polymer monomers to the crosslinking agent is 10:1.
[0009] In some embodiments, step (1) is performed in a glove box with H2O≤0.01 ppm and O2≤0.01 ppm.
[0010] In some embodiments, in step (1), the volume ratio of fluoroethylene carbonate to the polyfluorooxirane derivative is 7:3.
[0011] In some embodiments, in step (2), the molar ratio of lithium bistrifluoromethylsulfonylimide to the polymer monomers is 2:3.
[0012] In some embodiments, in step (3), the molar ratio of aluminum triflate to the polymer monomers is 1:150.
[0013] In some embodiments, in step (3), the in-situ polymerization is performed at 60°C for 5 h.
[0014] In a second aspect, the present application provides a quasi-solid-state polymer electrolyte obtained by the above preparation method.
[0015] In a third aspect, the present application provides a lithium ion battery comprising the quasi-solid-state polymer electrolyte.
[0016] In some embodiments, the lithium ion battery comprises Li metal as a negative electrode, ternary material (NCM811) as a positive electrode, and Celgard-2500 as a separator.
[0017] In some embodiments, the preparation method of the lithium ion battery comprises: in a glove box with an argon atmosphere (H2O≤0.01 ppm, O2≤0.01 ppm), using a 2032 stainless steel button cell shell, adding 80 μL of the precursor solution, assembling the battery with the negative electrode, the positive electrode and the separator under a pressure of 9 MPa, and polymerizing in situ in a 60°C oven for 5 h to obtain the lithium ion battery.
[0018] Technical effects
[0019] The conventional electrolyte is prone to form lithium dendrites, which pierce the separator and cause short circuits. The electrolyte has poor compatibility with the electrode interface, the interface impedance is large, and the battery performance is affected. The conventional polymer electrolyte is easily oxidized and decomposed at high voltage, which limits the improvement of the energy density of the battery. The present application introduces a polyfluoroethylene oxide derivative, which has strong electronegativity and chemical inertness, reduces the HOMO energy level of the polymer, inhibits oxidation and decomposition, and enhances high-voltage stability; forms a stable SEI / CEI film rich in LiF on the electrode surface, inhibits lithium dendrite growth and electrode material decomposition.
[0020] The non-in situ polymerization process is complicated, consumes a large amount of organic solvent, is not environmentally friendly and has poor economic efficiency. The present application uses an in situ polymerization technique to form a quasi-solid-state electrolyte, which allows the precursor solution to fully infiltrate the electrode to form a molecular-level close contact, reduces the interface impedance, and enhances the interface stability. Compared with the non-in situ polymerization electrolyte, the interface binding is better, and the preparation method is also simpler.
[0021] The charge distribution of the polyfluoroethylene oxide derivative is at both ends, and the polyfluoro end has excellent electron-withdrawing properties. Strong electronegativity changes the electron cloud distribution of the polymer chain, reduces the electron density, and inhibits oxidation. The quasi-solid-state polymer electrolyte of the present application reduces and decomposes to form a SEI / CEI film rich in LiF and Li3N on the electrode surface during the charging and discharging process Figure 4 ), which provides a physical barrier to prevent dendrite growth and side reactions. The liquid precursor is used to infiltrate the electrode surface, and after polymerization, a close contact is formed, reducing interface defects and side reactions, reducing interface impedance, and enhancing interface stability. The high-voltage stability of the electrolyte is improved, allowing the electrolyte to operate stably at high voltages above 4.5 V, matching high-voltage positive electrode materials such as NMC811 and LNMO, and improving the energy density of the battery. The stable SEI / CEI film formed inhibits lithium dendrite growth and electrode material decomposition, prolongs the cycle life of the battery, and improves the coulombic efficiency.
[0022] The present application utilizes the steric hindrance effect to hinder the regular arrangement of polymer chains with bulky fluorinated groups, reduce crystallinity, increase free volume and ion transmission channels, optimize the transmission path, and improve the rate performance of the battery. The in-situ polymerization process simplifies the electrolyte preparation steps, so that the electrolyte generates after being injected into the battery shell, avoiding the escape of organic solvents (generally more than 10%) during the external polymerization process, reducing the use of organic solvents, and being more environmentally friendly and economical.
[0023] The introduction of the polyfluoro-oxirane derivative of the present application significantly improves the oxidative decomposition potential of the electrolyte, enabling it to operate stably at a voltage of 4.5V or even higher. This not only widens the operating voltage window of the lithium metal battery, but also enables the battery to match high-voltage cathode materials such as NMC811 and LNMO, providing key support for improving the energy density of the battery. The quasi-solid-state electrolyte of the present application can form a stable solid electrolyte interface layer (SEI / CEI) on the surface of the lithium metal anode and the cathode, effectively inhibiting the growth of lithium dendrites and the decomposition of the electrode material. After multiple charge and discharge cycles, the capacity retention rate of the battery is still relatively high, for example, in some embodiments, after 400 cycles, the capacity retention rate can still reach 74.28%, which is much higher than the performance of traditional electrolytes, greatly extending the service life of the battery.
[0024] The lithium metal battery using the electrolyte exhibits a high initial coulombic efficiency, such as the efficiency of 93.2% in the examples, which indicates that the transmission and storage efficiency of lithium ions during the initial charge and discharge process is high, and the battery can more effectively utilize the active material of the lithium metal anode, which helps to improve the overall performance and energy density of the battery. BRIEF DESCRIPTION OF DRAWINGS
[0025] Figure 1 The LSV curves of the lithium metal batteries assembled with the electrolytes of Example 1, Example 2, and Comparative Example 1 and Comparative Example 2 are shown; Figure 2 The coulombic efficiency diagrams of the lithium metal batteries respectively assembled with the electrolytes of Example 1, Example 2, Example 3, and Comparative Example 1 and Comparative Example 2 are shown; Figure 3 The cycle performance diagrams of the lithium metal batteries respectively assembled with the electrolytes of Example 1, Example 2, Example 3, and Comparative Example 1 and Comparative Example 2 are shown; Figure 4 The XPS spectrum after the reaction of Example 1 and Comparative Example 1 is shown. DETAILED DESCRIPTION
[0026] The technical ideas and preferred embodiments of the present application are introduced below to make the technical content more clear and convenient to understand. The present application can be embodied in many different forms of technical ideas and embodiments, and the protection scope of the present application is not limited to the technical ideas and embodiments mentioned in the text.
[0027] Example 1
[0028] Pentafluoropropyl oxirane
[0029] Pentafluoropropyl oxirane raw materials are commercially available.
[0030] In an argon-filled glove box (H2O≤0.01ppm, O2≤0.01ppm), 3 mol of 1,3-dioxolane (DOL) was dissolved in a mixture of 0.7 ml of fluoroethylene carbonate and 0.3 ml of pentafluoropropyl oxirane, and 0.3 mol of crosslinking agent 2,2'-(2,2,3,4,4,5,5-octafluoro-hexane-1,6-diyl) bis(oxirane) (OFBO) was added after stirring, wherein the molar ratio of polymer monomer to crosslinking agent was 10:1, to obtain a monomer solution.
[0031] 2.0 M lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) was dissolved in 1 ml of the polymer monomer solution, and mixed uniformly to obtain a lithium salt solution, wherein the ratio of lithium bis(trifluoromethylsulfonyl)imide to polymer monomer was 2:3.
[0032] 20 mmol of aluminum triflate Al(OTf)3 was dissolved in the lithium salt solution, and mixed uniformly at a molar ratio of monomer to initiator of 150:1 to obtain a precursor solution, and the precursor solution was polymerized in situ at 60°C for 5h to obtain a quasi-solid-state electrolyte.
[0033] In-situ polymerization assembled Li||NCM811 battery
[0034] The preparation method of the Li||NCM811 battery is as follows: In an argon atmosphere (H2O≤0.01ppm, O2≤0.01ppm) glove box, a 2032 stainless steel button cell shell was used, Li metal was used as the negative electrode, ternary material (NCM811) was used as the positive electrode, Celgard-2500 was used as the separator to assemble the battery, 80 μL of the precursor solution obtained in Example 1 was added, and the battery was assembled under a pressure of 9 MPa. After assembly, the battery was polymerized in situ in a 60°C oven for 5h to obtain a Li||NCM811 battery.
[0035] Example 2
[0036] Heptafluorobutyl ethylene oxide
[0037] Heptafluorobutyl ethylene oxide is prepared by a metal fluoride-catalyzed fluorination method, specifically as follows: using pent-1-ene or hexafluoropentene (such as 1,1,1,3,4,4,5-heptafluoropentene) as raw materials, under gas-phase conditions, cobalt trifluoride (Co) is used... Using fluorine gas (F2) as a catalyst, 1,1,1,3,4,4,5-heptafluoropentene is reacted with fluorine gas (F2) at 270–400°C to generate heptafluoropentene (e.g., 2,2,3,3,4,4,5-heptafluoropent-1-ene). Then, using dichloromethane (DCM) or ethyl acetate as an oxidant, heptafluoropentene is mixed with mCPBA at 0°C to generate an ethylene oxide derivative. After quenching at room temperature, the mixture is subjected to layer extraction and purified by silica gel chromatography to obtain heptafluorobutylethylene oxide.
[0038] In an argon-filled glove box (H2O≤0.01ppm, O2≤0.01ppm), 3M 1,3-dioxapentane (DOL) was dissolved in a mixture of 0.7 ml of fluoroethylene carbonate and 0.3 ml of heptafluorobutyl ethylene oxide (Formula 3). After thorough stirring, 0.3M crosslinking agent 2,2'-(2,2,3,4,4,5,5-octafluorohexane-1,6-diyl)bis(ethylene oxide) (OFBO) was added, wherein the molar ratio of polymer monomer to crosslinking agent was 10:1, to obtain a monomer solution.
[0039] 2.0 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was dissolved in 1 ml of polymer monomer solution and mixed thoroughly to obtain a lithium salt solution, wherein the ratio of lithium bis(trifluoromethanesulfonyl)imide to polymer monomer was 2:3.
[0040] 20 mmol of aluminum trifluoromethanesulfonate Al(OTf)3 was dissolved in the lithium salt solution and mixed evenly to obtain a precursor solution. The precursor solution was subjected to in-situ polymerization at 60 °C for 5 h to obtain a quasi-solid electrolyte.
[0041] In-situ polymerization assembly of Li||NCM811 batteries
[0042] The preparation method of the Li||NCM811 battery is as follows: In an argon atmosphere (H2O≤0.01ppm, O2≤0.01ppm) glove box, using 2032 stainless steel button cell shell, using Li metal as the negative electrode, ternary material (NCM811) as the positive electrode, Celgard-2500 as the separator to assemble the battery, adding 80 μL of the precursor solution obtained in Example 2, assembling the battery under a pressure of 9 MPa, and after the completion of the assembly, in-situ polymerization reaction for 5 h in a 60°C oven to obtain a Li||NCM811 battery.
[0043] Example 3
[0044] Nonafluoropentyl oxirane
[0045] Nonafluoropentyl oxirane is prepared as follows: commercially available nonafluoropentyl alcohol (such as 2,2,3,3,4,4,5,5,5-nonafluoropentan-1-ol) is heated with concentrated sulfuric acid to reflux at 120°C for 2 hours to form 2,2,3,3,4,4,5,5,5-nonafluoropent-1-ene. The olefin is slowly mixed with meta-chloroperoxybenzoic acid (mCPBA) or hydrogen peroxide (H2O2) as an oxidizing agent at 0°C using dichloromethane (DCM) or ethyl acetate as a solvent, and after stirring for 1 hour, saturated sodium bicarbonate solution is added to quench, and after layer separation, extraction is performed with diethyl ether, and after drying, distillation purification is performed.
[0046] In an argon-filled glove box (H2O≤0.01ppm, O2≤0.01ppm), 3M of 1,3 dioxolane (DOL) is dissolved in a mixture of 0.7ml of fluoroethylene carbonate and 0.3ml of nonafluoropentyl oxirane, and after thorough stirring, 0.3M of crosslinking agent 2,2'-(2,2,3,4,4,5,5-octafluoro-hexane-1,6-diyl) bis(oxirane) (OFBO) is added, wherein the molar ratio of polymer monomer to crosslinking agent is 10:1, to obtain a monomer solution.
[0047] 2.0M of lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) is dissolved in 1ml of the polymer monomer solution, and after mixing, a lithium salt solution is obtained, wherein the ratio of lithium bis(trifluoromethylsulfonyl)imide to polymer monomer is 2:3.
[0048] 20mmol of aluminum triflate Al(OTf)3 is dissolved in the lithium salt solution, and after mixing, a precursor solution is obtained, and the precursor solution is in-situ polymerized at 60°C for 5h to obtain a polymer electrolyte.
[0049] In-situ polymerization assembly of Li||NCM811 battery
[0050] The preparation method of the Li||NCM811 battery is as follows: In an argon atmosphere (H2O≤0.01 ppm, O2≤0.01 ppm) glove box, a 2032 stainless steel button cell was used, Li metal as the negative electrode, ternary material (NCM811) as the positive electrode, Celgard-2500 as the separator to assemble the battery, 80 μL of the precursor solution obtained in Example 3 was added, and the battery was assembled under a pressure of 9 MPa. After assembly, in-situ polymerization was carried out in a 60°C oven for 5 h to obtain a Li||NCM811 battery.
[0051] Comparative Example 1
[0052] In an argon-filled glove box (H2O≤0.01 ppm, O2≤0.01 ppm), 3M of 1,3-dioxolane (DOL) was dissolved in a mixture of 0.7 ml of fluoroethylene carbonate (FEC) and 0.3 ml of ethyl methyl carbonate (EMC). After stirring, 0.3M of crosslinking agent 2,2'-(2,2,3,4,4,5,5-octafluoro-hexane-1,6-diyl) bis(oxymethylene) (OFBO) was added, and the molar ratio of polymer monomer to crosslinking agent was 10:1 to obtain a monomer solution.
[0053] 2.0M of lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) was dissolved in 1 ml of the polymer monomer solution, and mixed uniformly to obtain a lithium salt solution, wherein the ratio of lithium bis(trifluoromethylsulfonyl)imide to polymer monomer was 2:3.
[0054] 20 mmol of aluminum triflate Al(OTf)3 was dissolved in the lithium salt solution, and mixed uniformly to obtain a precursor solution. The precursor solution was in-situ polymerized at 60°C for 5 h to obtain a polymer electrolyte.
[0055] In-situ polymerization to assemble Li||NCM811 battery
[0056] The preparation method of the Li||NCM811 battery is as follows: In an argon atmosphere (H2O≤0.01 ppm, O2≤0.01 ppm) glove box, a 2032 stainless steel button cell was used, Li metal as the negative electrode, ternary material (NCM811) as the positive electrode, Celgard-2500 as the separator to assemble the battery, 80 μL of the precursor solution obtained in Example 3 was added, and the battery was assembled under a pressure of 9 MPa. After assembly, in-situ polymerization was carried out in a 60°C oven for 5 h to obtain a Li||NCM811 battery.
[0057] Comparative Example 2
[0058] In an argon-filled glove box (H2O≤0.01 ppm, O2≤0.01 ppm), a commercially available secondary electrolyte: 1.0 M lithium hexafluorophosphate (LiPF6) in fluorinated ethylene carbonate (FEC) and ethyl methyl carbonate (EMC) with a volume ratio of 7:3 was used.
[0059] In-situ polymerization assembled Li||NCM811 battery
[0060] The preparation method of the Li||NCM811 battery is as follows: In an argon-filled glove box (H2O≤0.01 ppm, O2≤0.01 ppm), a 2032 stainless steel button cell shell was used, Li metal was used as the negative electrode, ternary material (NCM811) was used as the positive electrode, Celgard-2500 was used as the separator to assemble the battery, 80 μL of the commercially available secondary electrolyte in Comparative Example 2 was added, and the battery was assembled under a pressure of 9 MPa. After assembly, the in-situ polymerization reaction was carried out in a 60°C oven for 5h, and the Li||NCM811 battery was obtained.
[0061] Effect implementation example
[0062] All the batteries used for electrochemical characterization were kept in a constant temperature room (Shanghai BOLAB Equipment Co., Ltd., BLC-300) at a temperature of 25±1°C. Unless otherwise specified, all tests were carried out at 25±1°C.
[0063] The electrochemical window was characterized by linear sweep voltammetry (LSV) on an electrochemical workstation (Shanghai CH Instruments, Inc. CHI760E) by linear sweep voltammetry (LSV) at a scan rate of 1 mV / s in the range of 2-5V on the assembled Li||SUS316 half-cell.
[0064] All the prepared Li||NCM811 batteries were tested on a LAND battery test system (CT3002A, Wuhan, China) and were charged and discharged in the voltage range of 2.8-4.3V and were tested for cycle performance at a current density of 0.5C.
[0065] The LSV curves of the lithium metal batteries assembled with the electrolytes of Example 1, Example 2 and Comparative Example 1, Comparative Example 2 are shown in Figure 1 .
[0066] The coulombic efficiency plots of the lithium metal batteries assembled with the electrolytes of Example 1, Example 2, Example 3 and Comparative Example 1, Comparative Example 2 are shown in Figure 2 .
[0067] The cycle performance plots of the lithium metal batteries assembled with the electrolytes of Example 1, Example 2, Example 3 and Comparative Example 1, Comparative Example 2 are shown in Figure 3 . XPS spectra after reaction of Example 1 and Comparative Example 1, part of the test data is shown in Table 1.
[0068] Table 1 Long cycle test data of lithium metal battery
[0069] From Table 1 and Figure 2 , Figure 3 It can be seen that the lithium metal battery assembled by the electrolyte containing the organic solvent of the application in the example has a higher first coulomb efficiency, and after 100 cycles, the capacity retention rate is higher than 90%, and can be stably operated for more than 300 cycles; while the lithium metal battery assembled by the existing electrolyte of Comparative Example One and Comparative Example Two has a lower first coulomb efficiency than that of the example, and after multiple cycles, the capacity retention rate is much lower than that of the lithium metal battery assembled by the electrolyte of the application.
[0070] The lithium metal battery assembled by the electrolyte of Example 2 has a first coulomb efficiency of 93.2%, and after 400 cycles, the capacity retention rate is 74.28%; while the lithium metal battery assembled by the electrolyte of Comparative Example 2 has a sudden capacity decay due to the growth of lithium dendrites after 35 cycles, and after 36 cycles, the capacity retention rate is only 23.87%; the lithium metal battery assembled by the quasi-solid polymer electrolyte of the polyfluorooxirane prepared by the application has a capacity retention rate much higher than that of the lithium metal battery assembled by the existing electrolyte and semi-solid electrolyte, and has high cycle stability and high cycle life.
[0071] From Figure 1 It can be seen that the electrolyte prepared by the example contains fluorine atoms in the polyfluorooxirane derivative, and the fluorine atom has a very strong electronegativity. In the in-situ polymerized semi-solid electrolyte, this electronegativity can change the electron cloud distribution around the polymer chain. When the lithium metal battery works at high voltage, the electrolyte is easy to be oxidized and decomposed. The presence of the polyfluorooxirane derivative makes the electron cloud more gather around the fluorine atom, reducing the electron density at other positions on the polymer chain, thereby reducing the possibility of electrolyte oxidation at high voltage, making the electrolyte still stable at a voltage above 4.8V, and making it better matched with the high-voltage positive electrode.
[0072] As Figure 4 shown, the quasi-solid polymer electrolyte generates an SEI / CEI film rich in LiF and Li3N on the electrode surface during the charging and discharging process, providing a physical barrier to prevent dendrite growth and side reactions. The liquid precursor is used to infiltrate the electrode surface, and after polymerization, a tight contact is formed, reducing interface defects and side reactions, reducing interface impedance, and enhancing interface stability.
[0073] The technical ideas and preferred embodiments of the present application are described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations without creative effort based on the concept of the present application. Therefore, any technical solutions obtained by logical analysis, reasoning or limited experiments based on the concept of the present application in the prior art should be within the protection scope defined by the claims.
Claims
1. A method for preparing a quasi-solid-state polymer electrolyte, comprising: (1) In an argon atmosphere, 1,3-dioxapentane was dissolved in a mixture of fluoroethylene carbonate and polyfluoroethylene oxide derivatives. After stirring, a crosslinking agent was added to obtain a polymer monomer solution. (2) Dissolve lithium bis(trifluoromethanesulfonyl)imide in the monomer solution to obtain a lithium salt solution; (3) Dissolve aluminum trifluoromethanesulfonate in the lithium salt solution and mix them evenly to obtain a precursor solution. Then polymerize the precursor solution in situ to obtain a quasi-solid polymer electrolyte.
2. The preparation method according to claim 1, wherein, In step (1), the polyfluoroethylene oxide derivative is selected from at least one of pentafluoropropyl ethylene oxide, heptafluorobutyl ethylene oxide, and nonafluoropentyl ethylene oxide.
3. The preparation method according to claim 1, wherein, In step (1), the crosslinking agent is 2,2'-(2,2,3,4,4,5,5-octafluorohexane-1,6-diyl)bis(ethylene oxide).
4. The preparation method according to claim 1, wherein, In step (1), 1,3-dioxapentane, fluoroethylene carbonate and polyfluoroethylene oxide derivative are all polymer monomers, and the molar ratio of the polymer monomer to the crosslinking agent is 10:
1.
5. The preparation method according to claim 1, wherein, At least one of the following must be met: In step (1), the volume ratio of fluoroethylene carbonate to polyfluoroethylene oxide derivative is 7:3; In step (2), the molar ratio of lithium bis(trifluoromethanesulfonyl)imide to the polymer monomer is 2:3; In step (3), the molar ratio of aluminum trifluoromethanesulfonate to polymer monomer is 1:150; In step (3), the in-situ polymerization is carried out in an oven at 60°C for 5 hours.
6. The quasi-solid polymer electrolyte obtained by the preparation method according to any one of claims 1-5.
7. A lithium-ion battery comprising the quasi-solid-state polymer electrolyte of claim 6.
8. The lithium-ion battery according to claim 7, wherein, The lithium-ion battery contains Li metal as the negative electrode, ternary material NCM811 as the positive electrode, and Celgard-2500 as the separator.
9. The lithium-ion battery according to claim 8, wherein, The method for preparing the lithium-ion battery includes: in a glove box under an argon atmosphere, using a 2032 stainless steel button battery case, adding 80 μL of the precursor solution, assembling the battery with a negative electrode, a positive electrode and a separator under a pressure of 9 MPa, and polymerizing in situ to obtain a lithium-ion battery.
10. The lithium-ion battery according to claim 9, wherein, The in-situ polymerization was carried out in a 60°C oven for 5 hours.