A urea-based pyrimidinone-terminated chain monomer, preparation method, application and gel battery and preparation method thereof
By introducing ureidopyrimidinone-terminated chain monomers into gel lithium batteries, a semi-interpenetrating network and quadruple hydrogen bonding effect are formed, solving the problems of low mechanical strength and poor electrochemical performance of gel electrolytes, and achieving high mechanical strength and excellent electrochemical performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DEEPAL AUTOMOBILE TECH CO LTD
- Filing Date
- 2022-09-30
- Publication Date
- 2026-07-24
AI Technical Summary
Existing gel electrolytes in gel lithium batteries suffer from low mechanical strength and poor electrochemical performance, especially when using silicon-based anode materials, they are difficult to adapt to electrode expansion.
Uriidine pyrimidinone-terminated chain monomers are used as additives. The chain monomers are prepared by nucleophilic addition reaction of isocyanate and amino groups to form a semi-interpenetrating network. This network combines with the cross-linked polymer in the gel electrolyte to enhance mechanical strength. Furthermore, the mechanical strength and self-healing ability of the electrolyte are improved by forming hydrogen bonds and quadruple hydrogen bonds with solvent molecules through the ureidine pyrimidinone functional groups.
It significantly improves the mechanical and electrochemical performance of gel batteries, with an ionic conductivity of 4.0 x 10⁻³ S/cm or higher, an electrochemical window of about 4.5 V, and a capacity retention of over 79% after 500 cycles at 25 °C and 1C. It also adapts to electrode expansion and exhibits excellent electrochemical performance.
Smart Images
Figure CN117089063B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium battery technology, specifically to a ureidopyrimidinone-terminated chain monomer, its preparation method, applications, and a gel battery and its preparation method. Background Technology
[0002] In recent years, lithium-ion batteries (LIBs) have attracted widespread attention due to their advantages of high output voltage, high energy density, and long cycle life. Currently, most lithium-ion batteries are based on liquid electrolyte systems using carbonate as a solvent. However, the safety issues of lithium-ion batteries are difficult to resolve due to the leakage and flammability of liquid electrolytes, as well as the uncontrollable growth of lithium dendrites when using liquid electrolytes. Therefore, using solid-state electrolytes instead of liquid organic electrolytes is considered an effective way to solve the safety problems of lithium-ion batteries. However, the low ionic conductivity of solid electrolytes at room temperature and the poor solid-solid interface between the electrodes and the solid electrolyte limit the practical application of all-solid-state lithium-ion batteries. Among these, gel polymer electrolytes, which combine the advantages of solid and liquid electrolytes and possess near-liquid ionic conductivity and good electrode interface contact, are considered a transitional product from liquid to solid-state batteries. Furthermore, research has found that gel polymer matrices have advantages such as good mechanical stability, interaction with solvent molecules, and the ability of gelation to prevent leakage of liquid electrolytes and inhibit lithium dendrite growth. Therefore, gel polymer electrolytes are considered to be the most promising electrolytes for lithium-ion batteries.
[0003] The literature Allan, Blanchard, Nikolai, et al. Long cycling, thermal stable, dendrites-free gel polymer electrolyte for flexible lithium metal batteries [C] / / 2018 International Conference on High Performance Computing & Simulation.0 discloses the use of tetraethylene glycol dimethyl ether as a solvent, LiTFSI as the lithium salt, and the preparation of a gel electrolyte membrane by copolymerization of methyl methacrylate and trimethylolpropane triacrylate, followed by battery assembly. However, this process is an in-situ preparation method, resulting in a large interfacial impedance between the electrolyte membrane and the electrode, leading to a very low conductivity of only 0.33 mS / cm. The literature Wang QJ, Zhang P, Wang B, et al. A novel gel polymer electrolyte based on trimethylolpropane trimethylacrylate / ionic liquid via in situ thermal polymerization for lithium-ion batteries[J]. Electrochimica Acta, 2021, 370(11):137706. discloses the successful preparation of a gel electrolyte with an ionic conductivity of 6.15 mS / cm by using azobisisoheptanenitrile as an initiator to polymerize trimethylolpropane trimethylacrylate in an ionic liquid. However, this gel system has excessive crosslinking, resulting in high brittleness and easy breakage, making it difficult to adapt to the expansion of silicon-based anode materials. Therefore, developing a gel electrolyte with high conductivity and the ability to adapt to electrode expansion is a technical problem that urgently needs to be solved in the industry. Summary of the Invention
[0004] One objective of this invention is to provide a ureidylpyrimidinone-terminated chain monomer, its preparation method, and its application, so as to provide a new additive for gel lithium batteries; another objective is to provide a gel battery and its preparation method to solve the problems of low mechanical strength and poor electrochemical performance of gel electrolytes in existing gel lithium batteries.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0006] A ureidopyrimidinone-terminated chain monomer, with the general structural formula shown in Formula I:
[0007]
[0008] Where n is a positive integer.
[0009] Preferably, the chain monomer is prepared by nucleophilic addition reaction of isocyanate-terminated polypropylene glycol with 6-methylisocytosine.
[0010] The present invention also provides a method for preparing the ureidopyrimidinone-terminated chain monomer, comprising the following steps:
[0011] Isocyanate-terminated polypropylene glycol was added to a heated and dissolved 6-methylisocytosine solution to carry out an addition reaction, thereby obtaining a chain monomer.
[0012] The reaction equation is:
[0013]
[0014] Based on the above-mentioned technical means, isocyanate-terminated polypropylene glycol is functionalized by a nucleophilic addition reaction between isocyanate and amino groups, thereby obtaining ureidopyrimidinone-terminated polypropylene glycol. The nucleophilic addition reaction between isocyanate and amino groups has the advantages of being fast, relatively complete, and having a high yield.
[0015] Preferably, it includes the following steps:
[0016] S1. Add 6-methylisocytosine to an organic solvent and heat to dissolve 6-methylisocytosine to obtain mixed solution A;
[0017] S2. Dissolve isocyanate-terminated polypropylene glycol in an organic solvent to obtain mixed solution B;
[0018] S3. Add mixed solution B dropwise into mixed solution A, let stand to remove the organic solvent, add petroleum ether to precipitate the target product, filter, wash, and dry to obtain the ureidopyrimidinone-terminated chain monomer.
[0019] Preferably, the molar ratio of 6-methylisocytosine to isocyanate-terminated polypropylene glycol is 2:1 to 2.5:1.
[0020] Preferably, the organic solvent is dimethyl sulfoxide;
[0021] In S1, the volume of dimethyl sulfoxide added for every 1g of 6-methylisocytosine is 10-50mL;
[0022] In S2, for every 1g of isocyanate-terminated polypropylene glycol, the corresponding volume of dimethyl sulfoxide added is 5 to 50 mL.
[0023] The organic solvent is removed by rotary evaporation after a standing time of more than 12 hours.
[0024] The present invention also provides the application of the ureidopyrimidinone-terminated chain monomer, which is used as an additive in gel batteries to enhance the mechanical strength of the gel batteries.
[0025] This invention also provides a method for preparing a gel battery, comprising the following steps:
[0026] S1. Add 6-methylisocytosine to an organic solvent and heat to dissolve 6-methylisocytosine to obtain mixed solution A; dissolve isocyanate-terminated polypropylene glycol in an organic solvent to obtain mixed solution B; add mixed solution B dropwise to mixed solution A, let stand, remove the organic solvent, add petroleum ether to precipitate the target product, filter, wash, and dry to obtain the first product;
[0027] S2. Add 1wt% to 20wt% of the polymer monomer, 0.1wt% to 5wt% of the first product and 0.1wt% to 1wt% of the initiator to the electrolyte in sequence, and mix to obtain a precursor solution;
[0028] S3. Inject the precursor solution into the soft-pack battery cell, and after encapsulation, react at a temperature of 50℃~80℃ for 1~5h to solidify in situ and form a gel electrolyte.
[0029] S4. Pre-charge the soft-pack cell that forms the gel electrolyte to obtain a gel battery;
[0030] The monomers used in the polymerization are olefin monomers, and the electrolyte includes lithium salts and organic solvents.
[0031] Based on the aforementioned technical means, by adding ureidylpyrimidinone-terminated chain monomers as additives to the electrolyte, the main chain of the monomer, being polypropylene glycol, can form a semi-interpenetrating network with the cross-linked polymer in the gel electrolyte to create a synergistic effect, thereby effectively improving the mechanical strength of the system. The ends of the chain monomers have ureidylpyrimidinone functional groups, which can form hydrogen bonds with solvent molecules, not only inhibiting solvent volatilization under heating but also effectively preventing electrolyte leakage. Furthermore, the ureidylpyrimidinone functional groups can form a quadruple hydrogen bond effect, which can further effectively improve the mechanical strength of the electrolyte system. Moreover, when the electrode expands and cracks, the quadruple hydrogen bond gel system also has self-repairing capabilities, thereby adapting to the expansion of the electrode and improving cycle performance.
[0032] Preferably, the olefin monomer is selected from one or more of methyl acrylate, methyl methacrylate, vinyl sulfite, pentaerythritol tetraacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, and bis(trimethylolpropane)tetraacrylate.
[0033] The initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, and benzoyl peroxide.
[0034] Preferably, the lithium salt is selected from one or more of LiPF6, LiClO4, LiAsF6, LiBF4, LiCH3SO3, LiCF3SO3, LiBOB, LiDFOB, LiN(FSO2)2, LiN(CF3SO2)2, LiTFSI and LiFSI, and the concentration of the lithium salt is 0.5 to 6 mol / L.
[0035] The organic solvent in the electrolyte is selected from one or more of carbonates, ethers, carboxylic acid esters, phosphate esters, and fluorinated solvents.
[0036] Preferably, the carbonate is selected from cyclic carbonates and / or chain carbonate compounds;
[0037] The ethers are selected from one or more of tetrahydrofuran (THF), 2-methyltetrahydrofuran, 1,3-dioxocyclopentane, dimethoxymethane, 1,2-dimethoxyethylene, and diethylene glycol dimethyl ether;
[0038] The carboxylic acid esters are selected from one or more of methyl formate, ethyl formate, ethyl propionate, propyl propionate, methyl butyrate, and ethyl acetate;
[0039] The phosphate esters are selected from one or more of trimethyl phosphite, triphenyl phosphite, and triphosphite;
[0040] The fluorinated solvent is selected from one or more of fluoroethylene carbonate, ethyl-2,2,2-trifluoroethyl carbonate, propylene trifluorocarbonate, and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether.
[0041] Preferably, the cyclic carbonate compound is selected from one or more of ethylene carbonate (EC), propylene carbonate (PC), γ-butyrolactone (GBL), and butylene carbonate;
[0042] The chain carbonate compound is preferably one or more of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, methyl ethyl carbonate (EMC), and carbonate derivatives synthesized from straight-chain or branched aliphatic monools with 3 to 8 carbon atoms and carbon dioxide.
[0043] The beneficial effects of this invention are:
[0044] 1) The oligomers containing ester groups and ether bonds provided by this invention and their preparation method involve functionalizing isocyanate-terminated polypropylene glycol through a nucleophilic addition reaction of isocyanate with an amino group, thereby obtaining ureidopyrimidinone-terminated polypropylene glycol. The nucleophilic addition reaction of isocyanate with an amino group has the advantages of fast reaction speed, relatively complete reaction, and high yield. Furthermore, the selected 6-methylisocytosine monomer has the advantage of wide availability of raw materials. Simultaneously, the preparation method has the advantages of low preparation cost, simple operation, mild conditions, and high conversion rate. Moreover, the resulting ureidopyrimidinone-terminated chain monomer can be used as an additive in the preparation of gel electrolytes in gel batteries, effectively improving the mechanical properties of gel batteries and providing a new direction for the development of gel batteries.
[0045] 2) The gel battery and its preparation method provided by this invention involve adding ureidylpyrimidinone-terminated chain monomers as additives to the electrolyte. The main chain of the monomer is polypropylene glycol, which can form a semi-interpenetrating network with the cross-linked polymer in the gel electrolyte to create a synergistic effect, thereby effectively improving the mechanical strength of the system. The ends of the chain monomers have ureidylpyrimidinone functional groups, which can form hydrogen bonds with solvent molecules, not only inhibiting solvent volatilization under heating but also effectively preventing electrolyte leakage. Furthermore, the ureidylpyrimidinone functional groups can form quadruple hydrogen bonds, further enhancing the mechanical strength of the electrolyte system. When the electrode expands and cracks, the quadruple hydrogen-bonded gel system also has self-repairing capabilities, adapting to electrode expansion and improving cycle performance. The resulting gel battery has an ionic conductivity of 4.0 x 10⁻⁶. - 3 With an S / cm or higher, an electrochemical window of around 4.5V, and a capacity retention of over 79% after 500 cycles at 25℃ and 1C, it exhibits excellent electrochemical performance and has significant potential for widespread application in the field of gel battery technology. Attached Figure Description
[0046] Figure 1 The graph shows the test results of the electrochemical window of the gel battery prepared in Example 5;
[0047] Figure 2 The graph shows the test results of the electrochemical window of the gel battery prepared in Example 6;
[0048] Figure 3 This is a graph showing the test results of the electrochemical window of the gel battery prepared in Example 7;
[0049] Figure 4 The graph shows the test results of the electrochemical window of the gel battery prepared in Comparative Example 1;
[0050] Figure 5 The graph shows the results of the room temperature cycle charge-discharge test of the gel battery prepared in Example 5.
[0051] Figure 6 The graph shows the results of the room temperature cycle charge-discharge test of the gel battery prepared in Example 6.
[0052] Figure 7 The graph shows the results of the room temperature cycle charge-discharge test of the gel battery prepared in Example 7. Detailed Implementation
[0053] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.
[0054] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.
[0055] Example 1
[0056] A method for preparing a ureidopyrimidinone-terminated chain monomer includes the following steps:
[0057] S1. Add 3.1g of 6-methylisocytosine to a three-necked flask containing 35mL of dimethyl sulfoxide, and then heat the system to 150℃ to completely dissolve the 6-methylisocytosine, to obtain mixture A;
[0058] S2. Dissolve 6g of isocyanate-terminated polypropylene glycol with an average molecular weight of 600g / mol in 180mL of dimethyl sulfoxide to obtain mixture B.
[0059] S3. Mixture B is slowly added dropwise to a three-necked flask containing mixture A through a constant pressure dropping funnel. After standing for 12 hours, dimethyl sulfoxide is removed by rotary evaporation. Then, petroleum ether is added to precipitate the target product. After filtration, the product is washed three times with ethanol and dried to obtain a ureidylpyrimidinone-terminated chain monomer.
[0060] Example 2
[0061] A method for preparing a ureidopyrimidinone-terminated chain monomer includes the following steps:
[0062] S1. Add 2.8g of 6-methylisocytosine to a three-necked flask containing 70mL of dimethyl sulfoxide, and then heat the system to 150℃ to completely dissolve the 6-methylisocytosine, to obtain mixture A;
[0063] S2. Dissolve 12g of isocyanate-terminated polypropylene glycol with an average molecular weight of 1200g / mol in 180mL of dimethyl sulfoxide to obtain mixture B.
[0064] S3. Mixture B is slowly added dropwise to a three-necked flask containing mixture A through a constant pressure dropping funnel. After standing for 12 hours, dimethyl sulfoxide is removed by rotary evaporation. Then, petroleum ether is added to precipitate the target product. After filtration, the product is washed three times with ethanol and dried to obtain a ureidylpyrimidinone-terminated chain monomer.
[0065] Example 3
[0066] A method for preparing a ureidopyrimidinone-terminated chain monomer includes the following steps:
[0067] S1. Add 2.5g of 6-methylisocytosine to a three-necked flask containing 125mL of dimethyl sulfoxide, and then heat the system to 150℃ to completely dissolve the 6-methylisocytosine, to obtain mixture A;
[0068] S2. Dissolve 22g of isocyanate-terminated polypropylene glycol with an average molecular weight of 2200g / mol in 110mL of dimethyl sulfoxide to obtain mixture B.
[0069] S3. Mixture B is slowly added dropwise to a three-necked flask containing mixture A through a constant pressure dropping funnel. After standing for 12 hours, dimethyl sulfoxide is removed by rotary evaporation. Then, petroleum ether is added to precipitate the target product. After filtration, the product is washed three times with ethanol and dried to obtain a ureidylpyrimidinone-terminated chain monomer.
[0070] Example 4
[0071] A method for preparing a ureidopyrimidinone-terminated chain monomer includes the following steps:
[0072] S1. Add 2.1g of 6-methylisocytosine to a three-necked flask containing 80mL of dimethyl sulfoxide, and then heat the system to 150℃ to completely dissolve the 6-methylisocytosine, to obtain mixture A;
[0073] S2. Dissolve 17g of isocyanate-terminated polypropylene glycol with an average molecular weight of 1700g / mol in 170mL of dimethyl sulfoxide to obtain mixture B;
[0074] S3. Mixture B is slowly added dropwise to a three-necked flask containing mixture A through a constant pressure dropping funnel. After standing for 12 hours, dimethyl sulfoxide is removed by rotary evaporation. Then, petroleum ether is added to precipitate the target product. After filtration, the product is washed three times with ethanol and dried to obtain a ureidylpyrimidinone-terminated chain monomer.
[0075] Example 5
[0076] A method for preparing a gel battery includes the following steps:
[0077] S1. Add 3.1 g of 6-methylisocytosine to a three-necked flask containing 35 mL of dimethyl sulfoxide, and then heat the system to 150 °C to completely dissolve the 6-methylisocytosine, to obtain mixture A; dissolve 6 g of isocyanate-terminated polypropylene glycol with an average molecular weight of 600 g / mol in 180 mL of dimethyl sulfoxide, to obtain mixture B; slowly add mixture B dropwise to the three-necked flask containing mixture A through a constant pressure dropping funnel, let it stand for 12 h, remove the dimethyl sulfoxide by rotary evaporation, then add petroleum ether to precipitate the target product, filter, wash three times with ethanol, and dry to obtain the first product;
[0078] S2. Take 4g of pentaerythritol tetraacrylate, 194.7g of electrolyte (1M LiTFSI in EC:EMC=1:1(V:V)) and 1g of the first product in a glove box and add them to a beaker. After adding a magnetic stir bar, stir evenly and then add 0.3g of azobisisobutyronitrile to obtain the precursor solution.
[0079] S3. Inject the precursor solution into the soft-pack battery cell, encapsulate it, and heat it in an oven at 60°C for 2 hours to solidify it in situ and form a gel electrolyte.
[0080] S4. The soft-pack cell that forms the gel electrolyte is pre-charged and formed to obtain a gel battery.
[0081] Example 6
[0082] A method for preparing a gel battery includes the following steps:
[0083] S1. Add 2.8 g of 6-methylisocytosine to a three-necked flask containing 70 mL of dimethyl sulfoxide, and then heat the system to 150 °C to completely dissolve the 6-methylisocytosine, obtaining mixture A; dissolve 12 g of isocyanate-terminated polypropylene glycol with an average molecular weight of 1200 g / mol in 180 mL of dimethyl sulfoxide, obtaining mixture B; slowly add mixture B dropwise to the three-necked flask through a constant pressure dropping funnel, obtaining mixture B; slowly add mixture B dropwise to the three-necked flask containing mixture A through a constant pressure dropping funnel, let stand for 12 h, remove dimethyl sulfoxide by rotary evaporation, then add petroleum ether to precipitate the target product, filter, wash three times with ethanol, and dry to obtain the first product;
[0084] S2. Take 6g of mixed monomers, 190.6g of electrolyte (1M LiFSI in EC:DEC:EMC=1:1:1(V:V:V)) and 3g of the first product in a glove box and add them to a beaker. After adding a magnetic stir bar, stir until homogeneous. Then add 0.4g of azobisisobutyronitrile to obtain the precursor solution. The mixed monomers are composed of pentaerythritol tetraacrylate and methyl acrylate in a mass ratio of 1:9.
[0085] S3. Inject the precursor solution into the soft-pack battery cell, encapsulate it, and heat it in an oven at 75°C for 5 hours to solidify it in situ and form a gel electrolyte.
[0086] S4. The soft-pack cell that forms the gel electrolyte is pre-charged and formed to obtain a gel battery.
[0087] Example 7
[0088] A method for preparing a gel battery includes the following steps:
[0089] S1. Add 2.5g of 6-methylisocytosine to a three-necked flask containing 125mL of dimethyl sulfoxide, and then heat the system to 150℃ to completely dissolve the 6-methylisocytosine, to obtain mixture A; dissolve 22g of isocyanate-terminated polypropylene glycol with an average molecular weight of 2200g / mol in 110mL of dimethyl sulfoxide, to obtain mixture B; slowly add mixture B dropwise to the three-necked flask containing mixture A through a constant pressure dropping funnel, let it stand for 12h, remove the dimethyl sulfoxide by rotary evaporation, then add petroleum ether to precipitate the target product, filter, wash three times with ethanol, and dry to obtain the first product;
[0090] S2. Take 5g of mixed monomers, 188.5g of electrolyte (1M LiFSI in EC:DEC:EMC = 1:1:1 (V:V:V)) and 6g of the first product in a glove box and add them to a beaker. After adding a magnetic stir bar, stir until homogeneous, and then add 0.5g of azobisisobutyronitrile to obtain the precursor solution. The mixed monomers are composed of polyethylene glycol dimethyl methacrylate and ethoxylated trimethylolpropane triacrylate in a mass ratio of 4:1.
[0091] S3. Inject the precursor solution into the soft-pack battery cell, encapsulate it, and heat it in an oven at 75°C for 2 hours to solidify it in situ and form a gel electrolyte.
[0092] S4. The soft-pack cell that forms the gel electrolyte is pre-charged and formed to obtain a gel battery.
[0093] Comparative Example 1
[0094] A method for preparing a gel battery includes the following steps:
[0095] S1. Add 2.5 wt% of mixed monomers to the electrolyte [1M LiFSI in EC:DEC:EMC=1:1:1(V:V:V)], stir until homogeneous, then add 0.25 wt% of azobisisobutyronitrile, stir until homogeneous to obtain the precursor solution; wherein, the mixed monomers are composed of polyethylene glycol dimethyl methacrylate and ethoxytrimethylolpropane triacrylate in a mass ratio of 4:1;
[0096] S2. Inject the precursor solution into the soft-pack battery cell, encapsulate it, and heat it in an oven at 75°C for 5 hours to solidify it in situ and form a gel electrolyte.
[0097] S3. The soft-pack cell that forms the gel electrolyte is pre-charged and formed to obtain a gel battery.
[0098] Detection and Analysis
[0099] 1) The in-situ cured gel electrolytes obtained in Examples 5 to 7 were prepared into strips of gel with dimensions of 40 mm × 8 mm × 0.5 mm by curing in a silicone rubber mold. Then, tensile tests were performed on each strip using a tensile testing machine to determine their tensile strength. The results are shown in Table 1.
[0100] Table 1 Tensile strength test results of gel electrolytes
[0101] Example 5 21.2 Example 6 28.7 Example 7 25.9 Comparative Example 1 2.6
[0102] As can be seen from the comparative analysis in Table 1, the gel electrolytes prepared in Examples 5 to 7, i.e., gel electrolytes with ureidopyrimidinone-terminated chain monomers, showed a significant increase in tensile strength compared to gel electrolytes without added chain monomers. This proves that the ureidopyrimidinone-terminated chain monomers in this application can significantly improve the mechanical strength of gel batteries.
[0103] 2) The gel batteries prepared in Examples 5 to 7 and Control Example 1 were subjected to ionic conductivity and electrochemical window tests, and charge-discharge tests were performed on the gel batteries prepared in Examples 5 to 7 and Control Example 1 at a 1C rate using constant current and constant voltage charging / discharging. The results are shown in Table 2 and... Figures 1 to 7 As shown:
[0104] Table 2. Test results of ionic conductivity, electrochemical window, and room temperature cycling performance of gel batteries.
[0105]
[0106] Through Table 2 and Figures 1 to 7 Analysis shows that the ionic conductivity of the gel batteries prepared in Examples 5 to 7 is all within the range of 4.0 x 10⁻⁶. -3 With an S / cm above 1, the electrochemical window is around 4.5V, and the capacity retention rate is above 79% after 500 cycles at 25℃ and 1C / 1C, it exhibits excellent electrochemical performance and has promotion and application value in the field of gel battery technology.
[0107] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.
Claims
1. A method for preparing a gel battery, characterized in that, Includes the following steps: S1. 6-Methylisocytosine is added to an organic solvent and heated to dissolve the 6-methylisocytosine, yielding a mixed solution A; isocyanate-terminated polypropylene glycol is dissolved in an organic solvent, yielding a mixed solution B; mixed solution B is added dropwise to mixed solution A, wherein the molar ratio of 6-methylisocytosine to isocyanate-terminated polypropylene glycol is 2:1 to 2.5:1; after standing, the organic solvent is removed, petroleum ether is added to precipitate the target product, and the product is filtered, washed, and dried to obtain the first product, which is a chain monomer with both ends capped by ureidinone; S2. Add 1wt%~20wt% of the polymer monomer, 0.1wt%~5wt% of the first product and 0.1wt%~1wt% of the initiator to the electrolyte in sequence, and mix to obtain the precursor solution; S3. Inject the precursor solution into the soft-pack battery cell, and after encapsulation, react at a temperature of 50℃~80℃ for 1~5h to solidify in situ and form a gel electrolyte. S4. Pre-charge the soft-pack cell that forms the gel electrolyte to obtain a gel battery; The polymerization monomer is an olefin monomer, and the electrolyte includes lithium salt and organic solvent; The olefin monomer is selected from one or more of methyl acrylate, methyl methacrylate, vinyl sulfite, pentaerythritol tetraacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, and bis(trimethylolpropane)tetraacrylate. The initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, and benzoyl peroxide.
2. The method for preparing a gel battery according to claim 1, characterized in that, The lithium salt is selected from one or more of LiPF6, LiClO4, LiAsF6, LiBF4, LiCH3SO3, LiCF3SO3, LiBOB, LiDFOB, LiN(FSO2)2 and LiN(CF3SO2)2, and the concentration of the lithium salt is 0.5~6 mol / L; The organic solvent in the electrolyte is selected from one or more of carbonates, ethers, carboxylic acid esters, phosphate esters, and fluorinated solvents.
3. The method for preparing a gel battery according to claim 2, characterized in that, The carbonates are selected from cyclic carbonates and / or chain carbonate compounds; The ethers are selected from one or more of tetrahydrofuran (THF), 2-methyltetrahydrofuran, 1,3-dioxocyclopentane, dimethoxymethane, 1,2-dimethoxyethylene, and diethylene glycol dimethyl ether; The carboxylic acid esters are selected from one or more of methyl formate, ethyl formate, ethyl propionate, propyl propionate, methyl butyrate, and ethyl acetate; The phosphate esters are selected from one or more of trimethyl phosphite, triphenyl phosphite, and triphosphite; The fluorinated solvent is selected from one or more of fluoroethylene carbonate, ethyl-2,2,2-trifluoroethyl carbonate, propylene trifluorocarbonate, and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether.
4. The method for preparing a gel battery according to claim 3, characterized in that, The cyclic carbonate compound is selected from one or more of ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate; The chain carbonate compounds are selected from one or more of dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), and carbonate derivatives synthesized from straight-chain or branched fatty monools with 3 to 8 carbon atoms and carbon dioxide.
5. The method for preparing a gel battery according to claim 1, characterized in that, The general structural formula of the first product is shown in Formula I: Formula I Where n is a positive integer.
6. The method for preparing a gel battery according to claim 1, characterized in that, In S1, the organic solvent is dimethyl sulfoxide, and the volume of dimethyl sulfoxide added is 10-50 mL for every 1 g of 6-methylisocytosine, and the volume of dimethyl sulfoxide added is 10-50 mL for every 1 g of isocyanate-terminated polypropylene glycol.