Polymer gel electrolyte precursor, polymer gel electrolyte, secondary battery and preparation method thereof
By optimizing the ratio of monomeric carbonate, monomeric fluorinated olefin, and crosslinking agent, a polymer gel electrolyte is formed, which solves the problems of lithium dendrite growth and high-temperature decomposition in liquid electrolytes, improves lithium-ion transport performance and electrochemical stability, and is suitable for the preparation of secondary batteries.
Patent Information
- Application Number
- CN202511685540.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-17
- Publication Date
- 2026-02-13
AI Technical Summary
Existing liquid electrolytes are prone to lithium dendrite growth during lithium metal anode cycling, decompose easily at high temperatures, and oxidize easily at high voltages. Furthermore, solid electrolytes have low ionic conductivity and poor interfacial contact, leading to a decline in electrochemical performance.
By using monomeric carbonate, monomeric fluorinated olefin, and crosslinking agent, the proportions of these components in the polymer gel electrolyte precursor are optimized to form a polymer gel electrolyte. The crosslinked structure is formed through free radical polymerization, thereby improving lithium-ion transport performance and high-voltage resistance.
It achieves good lithium-ion transport performance and high voltage resistance at room temperature, enhances the electrochemical stability and safety of the battery, simplifies the preparation process, and reduces costs.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of gel electrolyte, and in particular to a polymer gel electrolyte precursor, a polymer gel electrolyte, a secondary battery and a preparation method thereof. BACKGROUND
[0002] The practical application of traditional liquid electrolyte still faces three key challenges: firstly, lithium metal negative electrode is prone to uneven deposition during the cycle process, leading to lithium dendrite growth, which may pierce the separator and cause serious thermal runaway; secondly, the liquid electrolyte is prone to decomposition under high temperature conditions, causing a cliff-like attenuation of battery performance; thirdly, the liquid electrolyte is prone to oxidation under high voltage, limiting its application in high-voltage positive electrode materials.
[0003] In contrast, solid-state electrolyte (SSE) can inhibit lithium dendrite penetration and improve thermal stability to some extent due to its excellent chemical stability and high mechanical strength, thereby effectively alleviating the above problems. However, solid-state electrolyte also faces new challenges such as low ionic conductivity, poor electrode / electrolyte interface contact and increased interface impedance, resulting in decreased overall electrochemical performance.
[0004] Gel electrolyte, as a transition form between liquid and solid, not only retains high lithium ion conductivity, but also significantly improves electrochemical stability and safety. However, a gel electrolyte system capable of simultaneously achieving high lithium ion transference number and wide electrochemical stability window has not been effectively reported to date. SUMMARY
[0005] In order to solve at least one problem mentioned in the background, the present application provides a polymer gel electrolyte precursor, a polymer gel electrolyte, a secondary battery and a preparation method thereof. In the polymer gel electrolyte precursor of the present application, monomer carbonate, monomer fluorine-containing olefin and crosslinking agent are used, and the proportions of monomer carbonate, monomer fluorine-containing olefin and crosslinking agent in the polymer gel electrolyte precursor are optimized. Monomer carbonate, monomer fluorine-containing olefin and crosslinking agent react with each other when gelling to form a polymer gel electrolyte. The obtained polymer gel electrolyte exhibits good lithium ion transmission performance and high pressure resistance at room temperature.
[0006] The specific technical solutions provided by the embodiments of the present application are as follows: In a first aspect, a polymer gel electrolyte precursor is provided, which comprises a first monomer, a second monomer and a crosslinking agent, the first monomer comprising carbonate, and the second monomer comprising fluorine-containing olefin. The sum of the mass fractions of the first monomer, the second monomer and the crosslinking agent is 7% to 20% based on the total mass of the polymer gel electrolyte precursor.
[0007] In some optional embodiments of the present application, the mass fraction of the carbonate is 5% to 10%, the mass fraction of the fluorine-containing olefin is 1% to 5%, and the mass fraction of the crosslinking agent is 1% to 5% based on the total mass of the polymer gel electrolyte precursor.
[0008] In some optional embodiments of the present application, the mass fraction of the carbonate is 6% to 8%.
[0009] In some optional embodiments of the present application, the mass fraction of the fluorine-containing olefin is 3% to 5%.
[0010] In some optional embodiments of the present application, the mass fraction of the crosslinking agent is 3% to 5%.
[0011] The sum of the mass fractions of the first monomer, the second monomer and the crosslinking agent is 7% to 20% based on the total mass of the polymer gel electrolyte precursor.
[0012] In some optional embodiments of the present application, the mass ratio between the carbonate, the fluorine-containing olefin and the crosslinking agent is 1:(0.3 to 1.0):(0.2 to 0.5).
[0013] In some optional embodiments of the present application, the mass ratio between the total mass of the carbonate and the fluorine-containing olefin and the mass of the crosslinking agent is (2.0 to 6.0):1.
[0014] In some optional embodiments of the present application, the fluorine-containing olefin includes at least one of perfluorobutyl ethylene, heptafluoropent-1-ene, undecafluorohept-1-ene and pentadecafluoro-1-nonene.
[0015] In some optional embodiments of the present application, the carbonate includes vinylene carbonate.
[0016] In some optional embodiments of the present application, the crosslinking agent includes N,N-methylenebisacrylamide and / or poly(ethylene glycol) bisacrylamide.
[0017] In a second aspect, a polymer gel electrolyte is provided, which is prepared by gelation of the polymer gel electrolyte precursor described above.
[0018] In a third aspect, a secondary battery is provided, which includes a positive electrode, a negative electrode and the polymer gel electrolyte described above.
[0019] In a fourth aspect, a preparation method of a secondary battery is provided, which includes: The polymer gel electrolyte precursor is injected into the battery and left to stand, the polymer gel electrolyte precursor infiltrates the positive and negative electrodes of the battery, and the polymer gel electrolyte precursor is heated and cured to obtain the secondary battery.
[0020] In some optional embodiments of the present application, the preparation steps of the polymer gel electrolyte precursor include: The fluorine-containing lithium salt is added to the fluorine-containing carbonate plasticizer to obtain a first clear solution; The vinylene carbonate, the fluorine-containing olefin, and the crosslinking agent are added to the first clear solution to obtain a second clear solution; The azo initiator is added to the second clear solution to obtain the polymer gel electrolyte precursor.
[0021] Advantages: In the first aspect, the monomer carbonate, the monomer fluorine-containing olefin, and the crosslinking agent are included in the polymer gel electrolyte precursor of the present application, the proportions of the monomer carbonate, the monomer fluorine-containing olefin, and the crosslinking agent in the polymer gel electrolyte precursor are optimized, the monomer carbonate, the monomer fluorine-containing olefin, and the crosslinking agent react with each other when gelling, and the polymer gel electrolyte is formed.
[0022] In the second aspect, the alkyl chain structure in the monomer fluorine-containing olefin has good flexibility, which reduces the glass transition temperature (Tg) of the polymer gel and thus reduces the crystallinity of the polymer gel; the fluorine atoms in the monomer fluorine-containing olefin are conducive to the formation of hydrogen bonds, thereby forming a polymer crosslinking network with more stable structure in the polymer gel, and the presence of fluorine atoms also improves the high-pressure resistance of the polymer gel; the carbonate plasticizer contains polar groups, which are conducive to the absorption and binding of the residual liquid in the polymer gel on one hand, and conducive to the conduction of lithium ions on the other hand. The polymer gel electrolyte of the present application exhibits good lithium ion transmission performance and high-pressure resistance at room temperature.
[0023] In the third aspect, the crosslinking structure in the polymer gel electrolyte of the secondary battery of the present application can effectively absorb and fix the residual liquid in the polymer gel electrolyte, thereby inhibiting the side reactions of the polymer gel electrolyte on the surfaces of the positive and negative electrodes of the battery and enhancing the electrochemical stability of the battery.
[0024] In the fourth aspect, the preparation method of the secondary battery of the present application is simple and easy to implement, the raw material cost is low and safe and environmentally friendly, and is suitable for large-scale batch production. DETAILED DESCRIPTION
[0025] The present application will be further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.
[0026] In one embodiment, a polymer gel electrolyte precursor is provided, the polymer gel electrolyte precursor comprising: a first monomer, a second monomer and a crosslinking agent, the first monomer comprising a carbonate, the second monomer comprising a fluorine-containing olefin; The sum of the mass fractions of the first monomer, the second monomer and the crosslinking agent is 7% to 20% based on the total mass of the polymer gel electrolyte precursor.
[0027] In some optional embodiments of the present application, the mass fraction of the carbonate is 5% to 10%, the mass fraction of the fluorine-containing olefin is 1% to 5%, and the mass fraction of the crosslinking agent is 1% to 5% based on the total mass of the polymer gel electrolyte precursor.
[0028] In the above technical solution, the monomer carbonate, the monomer fluorine-containing olefin and the crosslinking agent in the present application undergo free radical polymerization to form a polymer gel in the precursor; during the reaction process, the monomer fluorine-containing olefin contains an alkyl chain structure, and the alkyl chain has good flexibility, which reduces the glass transition temperature (Tg) of the polymer gel, thereby reducing the crystallinity of the polymer gel; the fluorine atoms in the fluorine-containing olefin are conducive to the formation of hydrogen bonds, thereby forming a polymer crosslinking network with more stable structure in the polymer gel, and the presence of the fluorine atoms also improves the high-pressure resistance of the polymer gel. The carbonate contains a polar group, which is conducive to the absorption and binding of residual solution by the polymer gel on one hand, and is conducive to the conduction of lithium ions on the other hand. The crosslinking agent, the monomer carbonate and the monomer fluorine-containing olefin form a crosslinking structure through free radical polymerization, and this crosslinking structure can more effectively absorb and fix the residual liquid in the polymer gel electrolyte, inhibit the side reactions of the polymer gel electrolyte on the surface of the positive and negative electrodes, and enhance the electrochemical stability of the battery.
[0029] In some optional embodiments of the present application, the mass fraction of the carbonate is 6% to 8%.
[0030] In some optional embodiments of the present application, the mass fraction of the fluorine-containing olefin is 3% to 5%.
[0031] In some optional embodiments of the present application, the mass fraction of the crosslinking agent is 3% to 5%.
[0032] In some optional embodiments of the present application, the total mass fraction of the first monomer, the second monomer and the crosslinking agent is 12% to 18% based on the total mass of the polymer gel electrolyte precursor. The total mass fraction of the carbonate, the fluorine-containing olefin and the crosslinking agent is 12% to 18% in the precursor solution. If the total mass fraction of the three is too low, the binding ability of the three to the residual liquid in the polymer gel electrolyte is weak, and if the total mass fraction of the three is too high, the conductivity of the polymer gel electrolyte is reduced. Therefore, the total mass fraction of the three needs to be moderately controlled, so as to ensure sufficient binding ability of the three to the residual liquid in the polymer gel electrolyte while avoiding significant reduction of the conductivity of the polymer gel electrolyte due to excessive addition, so as to achieve a balance between mechanical stability and ionic conductivity.
[0033] In some optional embodiments of the present application, the mass ratio of the carbonate, the fluorine-containing olefin and the crosslinking agent is 1:(0.3 to 1.0):(0.2 to 0.5). If the amount of the crosslinking agent is high, the crosslinking degree of the system is high, which leads to low conductivity of the gel electrolyte, and if the amount of the crosslinking agent is too low, the stability of the gel structure is affected. If the amount of the carbonate is too low, the binding ability of the polymer to the residual liquid in the gel electrolyte is weakened, which affects the liquid retention and cycle performance of the electrolyte. If the amount of the fluorine-containing olefin is low, the high-pressure resistance of the system is weakened. Therefore, the amounts of the crosslinking agent, the carbonate and the fluorine-containing olefin need to be controlled within the above-mentioned ratio range, and the three are synergistically optimized, so as to achieve a balance between high conductivity, good mechanical stability and excellent high-pressure resistance.
[0034] In some optional embodiments of the present application, the mass ratio of the total mass of the carbonate and the fluorine-containing olefin to the mass of the crosslinking agent is (2.0 to 6.0):1.
[0035] In some optional embodiments of the present application, the fluorine-containing olefin includes at least one of perfluorobutyl ethylene, heptafluoropent-1-ene, undecafluorohept-1-ene and pentadecafluoro-1-nonene.
[0036] In some optional embodiments of the present application, the carbonate includes vinylene carbonate.
[0037] In some optional embodiments of the present application, the crosslinking agent includes N,N-methylenebisacrylamide and / or poly(ethylene glycol) bisacrylamide.
[0038] In another embodiment, a polymer gel electrolyte is provided, which is prepared by gelation of the polymer gel electrolyte precursor as described above.
[0039] In another embodiment, a secondary battery is provided, which includes a positive electrode, a negative electrode and the polymer gel electrolyte as described above.
[0040] In another embodiment, a preparation method of a secondary battery is provided, which includes: The polymer gel electrolyte precursor is injected into the battery and left to stand, the polymer gel electrolyte precursor infiltrates the positive electrode and the negative electrode of the battery, and the polymer gel electrolyte precursor is heated and cured to obtain the secondary battery.
[0041] In some optional embodiments of the present application, the current collector of the positive electrode is a carbon-coated aluminum foil, and the positive electrode material on the positive electrode comprises a high-voltage positive electrode composite material, and the high-voltage positive electrode composite material comprises at least one of a lithium iron phosphate material, a lithium manganese iron phosphate material, a lithium cobaltate material, and a nickel cobalt manganese 811 material.
[0042] In some optional embodiments of the present application, the negative electrode material on the negative electrode is a lithium metal.
[0043] In some optional embodiments of the present application, the separator comprises at least one of a cellulose separator, a polyethylene battery separator, a polypropylene battery separator, and a polyethylene / polypropylene composite battery separator.
[0044] In some optional embodiments of the present application, the preparation steps of the polymer gel electrolyte precursor comprise: The fluorine-containing lithium salt is added to the fluorine-containing carbonate plasticizer, and a first clear solution is obtained by stirring; The vinylene carbonate, the fluorine-containing olefin, and the crosslinking agent are added to the first clear solution, and a second clear solution is obtained by stirring; The azo initiator is added to the second clear solution, and the polymer gel electrolyte precursor is obtained by stirring.
[0045] In some optional embodiments of the present application, the fluorine-containing lithium salt comprises at least one of lithium bistrifluoromethanesulfonylimide, lithium bisfluorosulfonylimide, lithium difluoro(oxalato)borate, lithium hexafluorophosphate, and lithium tetrafluoroborate.
[0046] In some optional embodiments of the present application, the fluorine-containing carbonate plasticizer comprises at least one of fluorinated ethylene carbonate, difluorinated ethylene carbonate, and trifluorinated propylene carbonate.
[0047] In some optional embodiments of the present application, the azo initiator comprises at least one of dimethyl azobis isobutyrate, azobis isopropyl cyano, and azobis isobutyronitrile.
[0048] In some optional embodiments of the present application, the mass fraction of the fluorine-containing lithium salt is 1% to 20% and the mass fraction of the azo initiator is 0.001% to 0.075%, based on the total mass of the polymer gel electrolyte precursor.
[0049] The present application is further illustrated by the following examples and comparative examples. Unless otherwise specifically indicated, all raw materials, reagents, materials, and equipment used in the present application are commercially available products commonly used in the art.
[0050]
Example 1
[0051]
Embodiment 2
[0052]
Embodiment 3
[0053]
Embodiment 4
[0054]
Embodiment 5
[0055]
Embodiment 6
[0056]
Example 7
[0057]
Example 8
[0058]
Example 9
[0059]
Example 10
[0060]
Example 11
[0061] Comparative Example 1 This comparative example provides a method for preparing a polymer gel electrolyte precursor. The difference between this comparative example and Example 1 is that in step S2, the amount of vinylene carbonate in this comparative example is 0.9g, and it does not contain perfluorobutylethylene. The remaining steps are the same as in Example 1.
[0062] Comparative Example 2 This comparative example provides a method for preparing a polymer gel electrolyte precursor. The difference between this comparative example and Example 1 is that this comparative example does not contain vinylene carbonate in step S2, and the amount of perfluorobutylethylene is 0.9g. The remaining steps are the same as in Example 1.
[0063] Comparative Example 3 This comparative example provides a method for preparing a polymer gel electrolyte precursor. The difference between this comparative example and Example 1 is that in step S1, the amount of fluoroethylene carbonate is 8.0925 g, and in step S2, N,N'-methylenebisacrylamide is not present. The remaining steps are the same as in Example 1.
[0064] The contents of each substance in Examples 1 to 11 and Comparative Examples 1 to 3 are shown in Table 1.
[0065] Table 1
[0066] [Performance Testing] The polymer gel electrolytes used in the tests were prepared by injecting the polymer gel electrolyte precursors obtained in Examples 1-11 and Comparative Examples 1-3 into coin cells, followed by static impregnation and heating curing under an inert atmosphere. The entire battery assembly and testing process was completed in a glove box filled with high-purity argon (H2O < 0.1 ppm, O2 < 0.1 ppm). A CR2025 type coin cell assembly was used, including positive / negative electrode shells, a 12 mm diameter composite positive electrode, a 19 mm diameter separator, a 15.8 mm diameter stainless steel sheet, and a 15.8 mm outer diameter stainless steel spring sheet.
[0067] The polymer gel electrolyte precursor solution was quantitatively injected into the battery using a microsyringe to ensure full wetting of the electrodes and separator. After standing at room temperature for 2 hours, it was placed in a 60°C constant temperature oven for 6 hours to cure and form a stable polymer gel electrolyte membrane. Subsequently, a battery sealing machine was used to pressurize and seal the battery until the inner ring scale reached 500 psi, obtaining a well-sealed test battery.
[0068] Based on the different performance requirements, corresponding battery configurations are used for characterization: 1. Ionic conductivity testing – Double-blocking electrode cell method Battery structure: Positive electrode shell | Stainless steel sheet | Gel electrolyte | Separator | Gel electrolyte | Stainless steel sheet | Spring sheet | Negative electrode shell.
[0069] Ionic conductivity was determined by alternating current impedance spectroscopy. The test frequency range was 1 Hz to 1 MHz, and the AC voltage amplitude was 10 mV. The bulk resistance (R6) of the electrolyte was obtained from the Nyquist plot. Ionic conductivity (σ) was calculated using the formula σ = L / (R6·A), where L is the electrolyte film thickness (cm) and A is the effective contact area of the electrode (cm²). The test results were the average of three parallel samples.
[0070] 2. Electrochemical window upper limit test – single-blocked electrode cell method Battery structure: Positive electrode shell | Lithium sheet | Gel electrolyte | Separator | Gel electrolyte | Stainless steel sheet | Spring sheet | Negative electrode shell.
[0071] Oxidation stability was determined by linear sweep voltammetry (LSV). The scan range was from open circuit potential to 6.0 V (vs. Li). + / Li), with a scan rate of 0.1 mV / s. The upper limit of the electrochemical window is defined as the voltage value corresponding to the current density rising to 0.1 mA / cm². Each group of samples was tested three times, and the average value was taken.
[0072] 3. Lithium-ion transference number test – Lithium-symmetric cell method Battery structure: Positive electrode shell | Lithium sheet | Gel electrolyte | Separator | Gel electrolyte | Lithium sheet | Stainless steel sheet | Spring sheet | Negative electrode shell.
[0073] Lithium-ion transference number was determined by combining constant-voltage polarization and AC impedance spectroscopy. First, a 10 mV DC voltage was applied for polarization, and the initial current (I0) and steady-state current (I0) were recorded. ss AC impedance tests were performed before and after polarization to obtain the initial resistance (R0) and steady-state resistance (R). ss Lithium-ion transport number (t) + Calculated according to the Bruce–Vincent–Evans formula: t + = [I ss (V − I0R0)] / [I0(V −I ss R ss )]; Where V is the polarization voltage (10 mV). Each group of samples was tested at least three times, and the average value was taken as the final result.
[0074] The test data of ionic conductivity, upper limit of electrochemical window and lithium-ion transference number obtained in Examples 1 to 11 and Comparative Examples 1 to 3 are shown in Table 2.
[0075] Table 2
[0076] As shown in Table 2, the ionic conductivity of Examples 1 to 11 ranges from 5.02 mS / cm to 8.60 mS / cm, the upper limit of the electrochemical window is 5.01 V to 5.58 V, and the lithium-ion transference number ranges from 0.55 to 0.72. The ionic conductivity of Comparative Examples 1 to 3 ranges from 3.26 mS / cm to 4.10 mS / cm, the upper limit of the electrochemical window is 4.34 V to 4.51 V, and the lithium-ion transference number ranges from 0.43 to 0.51.
[0077] Comparative Example 1 lacks the second monomer compared to Example 1, Comparative Example 2 lacks the first monomer compared to Example 1, and Comparative Example 3 lacks the crosslinking agent compared to Example 1. The ionic conductivity, upper limit of the electrochemical window, and lithium-ion transference number measured in Comparative Examples 1 to 3 are all lower than those in Example 1. This indicates that the absence of any component (first monomer, second monomer, or crosslinking agent) in this application leads to a decrease in the ionic conductivity, upper limit of the electrochemical window, and lithium-ion transference number of the battery, thus demonstrating that the first monomer, second monomer, and crosslinking agent work synergistically in this application, and none of them can be omitted.
[0078] The only difference between Examples 1 to 4 is the type of the second monomer. The ionic conductivity ranges from 6.36 mS / cm to 6.40 mS / cm, the upper limit of the electrochemical window is from 5.10 V to 5.36 V, and the lithium-ion transference number ranges from 0.61 to 0.64. Different types of second monomers can keep the ionic conductivity, the upper limit of the electrochemical window, and the lithium-ion transference number within a good range.
[0079] Example 5 increased the content of the first monomer compared to Example 1. The ionic conductivity measured in Example 5 was 7.03 mS / cm, the upper limit of the electrochemical window was 5.08 V, and the lithium-ion transference number was 0.56.
[0080] Compared with Example 5, Example 6 changed the type of crosslinking agent. After changing the type of crosslinking agent, the ionic conductivity measured in Example 6 was 6.14 mS / cm, the upper limit of the electrochemical window was 5.16, and the lithium ion transference number was 0.58.
[0081] Example 7 increased the content of the second monomer compared to Example 1. The ionic conductivity measured in Example 7 was 6.43 mS / cm, the electrochemical window was 5.23 V, and the lithium-ion transference number was 0.6.
[0082] Example 8 reduced the content of the second monomer compared to Example 1, and the ionic conductivity measured in Example 8 was [missing value]. The electrochemical window has a flux density of 6.65 mS / cm, a voltage of 5.03 V, and a lithium-ion transference number of 0.65.
[0083] Example 9 increased the crosslinking agent content compared to Example 5. The ionic conductivity measured in Example 9 was 5.02 mS / cm, the electrochemical window was 5.44 V, and the lithium-ion transference number was 0.70.
[0084] Example 10 increased the content of the first monomer compared to Example 9. The ionic conductivity measured in Example 10 was 6.15 mS / cm, the electrochemical window was 5.58 V, and the lithium-ion transference number was 0.72.
[0085] Compared to Example 8, Example 11 reduced the content of the first monomer and crosslinking agent. The ionic conductivity measured in Example 11 was 8.6 mS / cm, the electrochemical window was 5.01, and the lithium-ion transference number was 0.55.
[0086] As shown in Table 2, the polymer electrolytes prepared in Examples 1 to 7 and Example 10 exhibited good overall electrochemical performance when the total mass fraction of the first monomer, the second monomer, and the crosslinking agent was controlled at 12% to 18%, and the mass ratio of the three components was maintained within the range of 1:(0.3 to 1.0):(0.2 to 0.5). For Examples 1 to 7 and Example 10, by adjusting the proportions of each component within this composition range, the ionic conductivity remained stable between 6.14 and 8.60 mS / cm; the upper limit of the electrochemical window reached 5.08 V to 5.58 V, suitable for high-voltage battery systems; and the lithium-ion transference number ranged between 0.58 and 0.72. These results indicate that within a defined ratio range, a good balance can be achieved between ionic conductivity, electrochemical stability, and ionic selectivity by rationally controlling the proportions of the first monomer, the second monomer, and the crosslinking agent.
[0087] Although preferred embodiments have been described in this application, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of this application.
[0088] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.
Claims
1. A polymer gel electrolyte precursor, characterized in that, The polymer gel electrolyte precursor comprises: a first monomer, a second monomer, and a crosslinking agent, wherein the first monomer comprises a carbonate and the second monomer comprises a fluorinated olefin. Based on the total mass of the polymer gel electrolyte precursor, the sum of the mass fractions of the first monomer, the second monomer, and the crosslinking agent is 7% to 20%.
2. The polymer gel electrolyte precursor as described in claim 1, characterized in that, Based on the total mass of the polymer gel electrolyte precursor, the mass fraction of the carbonate is 5% to 10%, the mass fraction of the fluorinated olefin is 1% to 5%, and the mass fraction of the crosslinking agent is 1% to 5%. Preferably, the carbonate has a mass fraction of 6% to 8%; Preferably, the mass fraction of the fluorinated olefin is 3% to 5%; Preferably, the crosslinking agent has a mass fraction of 3% to 5%.
3. The polymer gel electrolyte precursor as described in claim 1, characterized in that, Based on the total mass of the polymer gel electrolyte precursor, the sum of the mass fractions of the first monomer, the second monomer, and the crosslinking agent is 12% to 18%.
4. The polymer gel electrolyte precursor as described in claim 1, characterized in that, The mass ratio of the carbonate, the fluorinated olefin, and the crosslinking agent is 1:(0.3 ~ 1.0):(0.2 ~ 0.5). Preferably, the mass ratio of the total mass of the carbonate and the fluorinated olefin to the mass of the crosslinking agent is (2.0 ~ 6.0):
1.
5. The polymer gel electrolyte precursor as described in claim 1, characterized in that, The fluorinated olefins include at least one of perfluorobutylethylene, heptafluoropent-1-ene, undecylfluorohept-1-ene, and pentadecylfluoro-1-nonene.
6. The polymer gel electrolyte precursor as described in claim 1, characterized in that, The carbonate includes vinylene carbonate.
7. The polymer gel electrolyte precursor as described in claim 1, characterized in that, The crosslinking agent includes N,N-methylenebisacrylamide and / or poly(ethylene glycol)diacrylamide.
8. A polymer gel electrolyte, characterized in that, It is prepared by gelation of the polymer gel electrolyte precursor as described in any one of claims 1 to 7.
9. A secondary battery, characterized in that, The secondary battery includes a positive electrode, a negative electrode, and a polymer gel electrolyte as described in claim 8.
10. A method for preparing a secondary battery, characterized in that, The preparation method includes: After injecting the polymer gel electrolyte precursor as described in any one of claims 1 to 7 into the battery and allowing it to stand, the polymer gel electrolyte precursor wets the positive and negative electrodes of the battery and is then heated and cured to obtain a secondary battery. Preferably, the preparation steps of the polymer gel electrolyte precursor include: Fluorinated lithium salts were added to fluorocarbonate plasticizers and stirred to obtain a first clear solution; Add vinylene carbonate, fluorinated olefin and crosslinking agent to the first clear solution, and stir to obtain a second clear solution; An azo initiator was added to the second clarified solution, and the mixture was stirred to obtain the polymer gel electrolyte precursor.