Composite gel polymer electrolyte and preparation method thereof, supercapacitor
By combining a modified polymer backbone with surface-functionalized niobium oxide nanoparticles, a three-dimensional network structure composite gel polymer electrolyte was constructed, which solved the problems of low ionic conductivity, poor high-temperature stability, and weak mechanical strength of existing gel polymer electrolytes, and realized a high-performance supercapacitor.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XIAN THERMAL POWER RES INST CO LTD
- Filing Date
- 2026-02-11
- Publication Date
- 2026-06-23
AI Technical Summary
Existing gel polymer electrolytes in supercapacitors suffer from low ionic conductivity, poor high-temperature stability, weak mechanical strength, and poor electrode interface compatibility, resulting in short device cycle life and insufficient safety for high-temperature use.
A modified polymer backbone was prepared by condensation reaction of hydroxylated polyvinylidene fluoride-hexafluoropropylene and nitrogen-containing heterocyclic silane modifier. Surface-functionalized hydroxylated niobium oxide nanoparticles were dispersed and impregnated with organic solvent and lithium salt to form a three-dimensional network structure of composite gel polymer electrolyte. An in-situ polymerization process was then used to construct an interpenetrating three-dimensional network of polymer and inorganic particles.
It achieves high ionic conductivity, excellent mechanical properties and long cycle stability, improves the thermal stability of the electrolyte and the compatibility of the electrode interface, and extends the service life of the supercapacitor.
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Figure CN121687741B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of supercapacitors, and in particular to composite gel polymer electrolytes and their preparation methods, and supercapacitors. Background Technology
[0002] Gel polymer electrolytes are the core components of supercapacitors. Existing products generally suffer from problems such as low ionic conductivity, poor high-temperature stability, weak mechanical strength, and poor electrode interface compatibility, resulting in short device cycle life and insufficient safety for high-temperature use. This makes it difficult to meet the demand for high-performance energy storage devices in the new energy field. There is an urgent need to develop composite gel polymer electrolytes that combine high conductivity and stability. Summary of the Invention
[0003] This application proposes a composite gel polymer electrolyte and its preparation method, as well as a supercapacitor, to address the deficiencies of the prior art.
[0004] According to a first aspect of the embodiments of this application, a composite gel polymer electrolyte is provided, comprising:
[0005] A modified polymer backbone was prepared by condensation reaction of hydroxylated polyvinylidene fluoride-hexafluoropropylene and a nitrogen-containing heterocyclic silane modifier.
[0006] Surface-functionalized hydroxylated niobium oxide nanoparticles dispersed in the modified polymer framework;
[0007] Organic solvent and lithium salt impregnated in the modified polymer backbone, which is a three-dimensional network structure generated by a crosslinking agent.
[0008] In some embodiments, the nitrogen-containing heterocyclic silane modifier is N-(3-triethoxysilylpropyl)-4-methylpyridine bromide; the amount of the nitrogen-containing heterocyclic silane modifier added is 4% to 15% of the mass of the hydroxylated polyvinylidene fluoride-hexafluoropropylene.
[0009] In some embodiments, the surface-functionalized hydroxylated niobium oxide nanoparticles are prepared by a condensation reaction of hydroxylated niobium oxide nanoparticles and methacryloxypropyltrimethoxysilane; the amount of surface-functionalized hydroxylated niobium oxide nanoparticles added is 4% to 12% of the mass of the modified polymer backbone.
[0010] In some embodiments, the organic solvent is a mixture of propylene carbonate and diethyl carbonate, wherein the volume ratio of propylene carbonate to diethyl carbonate ranges from 1:4 to 4:1.
[0011] In some embodiments, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide, and the concentration of lithium bis(trifluoromethanesulfonyl)imide in the composite gel polymer electrolyte is from 0.6 mol / L to 1.5 mol / L.
[0012] In some embodiments, the crosslinking agent is ethylene glycol dimethacrylate, and the amount of ethylene glycol dimethacrylate added is 2% to 5% of the mass of the modified polymer backbone.
[0013] According to a second aspect of the embodiments of this application, a preparation method is provided for preparing a composite gel polymer electrolyte as described above, comprising:
[0014] Preparation of hydroxylated polyvinylidene fluoride-hexafluoropropylene;
[0015] The hydroxylated polyvinylidene fluoride-hexafluoropropylene is reacted with a nitrogen-containing heterocyclic silane modifier to obtain a modified polymer backbone;
[0016] Hydroxylated niobium oxide nanoparticles were prepared, and the hydroxylated niobium oxide nanoparticles were surface functionalized to synthesize surface-functionalized hydroxylated niobium oxide nanoparticles.
[0017] Under an inert atmosphere, the modified polymer backbone, the surface-functionalized hydroxylated niobium oxide nanoparticles, an organic solvent, a lithium salt, a crosslinking agent, and an initiator are mixed to prepare a prepolymer solution.
[0018] The prepolymer solution is subjected to in-situ polymerization and gelation to obtain the composite gel polymer electrolyte.
[0019] In some embodiments, the reaction of the hydroxylated polyvinylidene fluoride-hexafluoropropylene with a nitrogen-containing heterocyclic silane modifier includes:
[0020] In the presence of the catalyst dibutyltin dilaurate, the hydroxylated polyvinylidene fluoride-hexafluoropropylene and the nitrogen-containing heterocyclic silane modifier are reacted in anhydrous toluene at 70-90°C for 8-12 hours.
[0021] In some embodiments, the in-situ polymerization and gelation of the prepolymer liquid includes:
[0022] The prepolymer solution is polymerized in situ at 50-60°C for 4-8 hours, and then vacuum dried at 40-50°C for 12-20 hours to complete the gelation.
[0023] According to a third aspect of this application, a supercapacitor is provided, characterized in that it comprises a composite gel polymer electrolyte as described above.
[0024] The beneficial effects of the composite gel polymer electrolyte and its preparation method, and the supercapacitor described in this application embodiment, include at least the following:
[0025] Compared with existing gel polymer electrolyte technology, the core advantage of the embodiments of this application stems from the synergistic mechanism of "polymer skeleton-modifier-inorganic filler". Specifically, it includes at least the following: using hydroxylated polyvinylidene fluoride-hexafluoropropylene as the polymer backbone, whose highly polar -CF2 groups help improve the affinity and retention of electrolyte; introducing a nitrogen-containing heterocyclic silane modifier, which optimizes the ion transport path through the coordination of heterocyclic nitrogen atoms with lithium ions, and whose silicon-oxygen bond structure also helps improve the thermal stability and electrochemical window stability of the electrolyte; compounded surface-functionalized hydroxylated nano-niobium oxide, whose physical support of nanoparticles can enhance the mechanical strength of the electrolyte, and whose abundant hydroxyl groups on the surface can regulate the lithium ion desolvation process and suppress side reactions at the electrode interface, while its high dielectric constant helps to reduce the charge transfer impedance at the electrolyte / electrode interface and improve interfacial compatibility; finally, the polymer and inorganic particle interpenetrating three-dimensional network constructed by in-situ polymerization process strengthens the interfacial bonding between components and avoids filler agglomeration, thereby synergistically achieving a comprehensive improvement in high ionic conductivity, good mechanical properties, excellent thermal stability and interfacial compatibility. Attached Figure Description
[0026] Figure 1 This is a schematic flowchart of a preparation method according to an embodiment of this application;
[0027] Figure 2 The figures show the experimental results of ionic conductivity for Examples 1 to 16 and Comparative Examples 1 and 2 of this application.
[0028] Figure 3 The diagrams show the impedance results of Embodiments 6 and 8, and Comparative Examples 1 and 2 of this application. Detailed Implementation
[0029] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the various embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and with various variations and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of this disclosure. The various embodiments can be combined with and referenced by each other without contradiction.
[0030] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed embodiments of the present application, but merely to illustrate selected embodiments of the present application. Other embodiments obtained by those skilled in the art based on the embodiments of the present application without inventive effort are all within the scope of protection of the embodiments of the present application.
[0031] This application discloses a composite gel polymer electrolyte and its preparation method, as well as a supercapacitor. The preparation method is used to prepare the composite gel polymer electrolyte, aiming to overcome the shortcomings of the prior art. It addresses the technical problems of existing gel polymer electrolytes in supercapacitor applications, such as insufficient ionic conductivity, poor high-temperature stability, weak mechanical strength, and poor compatibility with the electrode interface leading to short cycle life. The composite gel polymer electrolyte of this application combines high ionic conductivity, excellent mechanical properties, and long cycle stability.
[0032] See attached document Figure 1 As shown, the composite gel polymer electrolyte comprises: a modified polymer skeleton prepared by condensation reaction of hydroxylated polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and a nitrogen-containing heterocyclic silane modifier; surface-functionalized hydroxylated nano-niobium oxide dispersed in the modified polymer skeleton; an organic solvent and a lithium salt impregnated in the modified polymer skeleton, wherein the modified polymer skeleton is a three-dimensional network structure generated by a crosslinking agent.
[0033] For example, the hydroxylation pretreatment of polyvinylidene fluoride-hexafluoropropylene includes: dissolving polyvinylidene fluoride-hexafluoropropylene in N,N-dimethylformamide, adding monoethanolamine, reacting at 80-100°C for 6-10 hours under nitrogen protection, and obtaining hydroxylated polyvinylidene fluoride-hexafluoropropylene after precipitation, washing, and drying. The CAS number of this polyvinylidene fluoride-hexafluoropropylene is 9011-17-0.
[0034] In this application, the modified polymer skeleton can be understood as polyvinylidene fluoride-hexafluoropropylene modified with nitrogen-containing heterocyclic silane.
[0035] An example of the synthesis of nitrogen-containing heterocyclic silane-modified polyvinylidene fluoride-hexafluoropropylene includes: dissolving hydroxylated polyvinylidene fluoride-hexafluoropropylene in anhydrous toluene, adding dibutyltin dilaurate catalyst, adding a nitrogen-containing heterocyclic silane modifier dropwise, reacting at 70-90℃ for 8-12 h, and obtaining nitrogen-containing heterocyclic silane-modified polyvinylidene fluoride-hexafluoropropylene by precipitation, washing, and drying.
[0036] For example, the nitrogen-containing heterocyclic silane modifier is N-(3-triethoxysilylpropyl)-4-methylpyridine bromide; the amount of the nitrogen-containing heterocyclic silane modifier added is 4% to 15% of the mass of the hydroxylated polyvinylidene fluoride-hexafluoropropylene.
[0037] For example, the surface-functionalized hydroxylated niobium oxide nanoparticles (Nb2O5) are prepared by condensation reaction of hydroxylated niobium oxide nanoparticles and methacryloxypropyltrimethoxysilane; the amount of the surface-functionalized hydroxylated niobium oxide nanoparticles added is 4% to 12% of the mass of the modified polymer backbone.
[0038] For example, the preparation of hydroxylated niobium oxide nanoparticles includes: dispersing niobium oxide nanoparticles in deionized water to form a suspension, adjusting the pH to 1.5-2.5, reacting at 80-90℃ for 3-5 hours, and obtaining hydroxylated niobium oxide nanoparticles by centrifugation, washing, and drying.
[0039] For another example, the synthesis of surface-functionalized hydroxylated niobium oxide nanoparticles includes: dispersing hydroxylated niobium oxide nanoparticles in anhydrous ethanol, adding silane coupling agent KH570, reacting at 60-70℃ for 2-4 hours under nitrogen protection, and obtaining functionalized niobium oxide nanoparticles by centrifugation, washing, and drying.
[0040] For example, the organic solvent is a mixture of propylene carbonate (PC) and diethyl carbonate (DEC), wherein the volume ratio of propylene carbonate to diethyl carbonate ranges from 1:4 to 4:1.
[0041] For example, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and the concentration of lithium bis(trifluoromethanesulfonyl)imide in the composite gel polymer electrolyte is from 0.6 mol / L to 1.5 mol / L.
[0042] In some embodiments, the crosslinking agent is ethylene glycol dimethacrylate (EGDMA), and the amount of EGDMA added is 2% to 5% of the mass of the modified polymer backbone.
[0043] Compared with existing gel polymer electrolyte technology, the core advantage of the embodiments of this application stems from the synergistic mechanism of "polymer skeleton-modifier-inorganic filler". Specifically, it includes at least the following: using hydroxylated polyvinylidene fluoride-hexafluoropropylene as the polymer backbone, whose highly polar -CF2 groups help improve the affinity and retention of electrolyte; introducing a nitrogen-containing heterocyclic silane modifier, which optimizes the ion transport path through the coordination of heterocyclic nitrogen atoms with lithium ions, and whose silicon-oxygen bond structure also helps improve the thermal stability and electrochemical window stability of the electrolyte; compounded surface-functionalized hydroxylated nano-niobium oxide, whose physical support of nanoparticles can enhance the mechanical strength of the electrolyte, and whose abundant hydroxyl groups on the surface can regulate the lithium ion desolvation process and suppress side reactions at the electrode interface, while its high dielectric constant helps to reduce the charge transfer impedance at the electrolyte / electrode interface and improve interfacial compatibility; finally, the polymer and inorganic particle interpenetrating three-dimensional network constructed by in-situ polymerization process strengthens the interfacial bonding between components and avoids filler agglomeration, thereby synergistically achieving a comprehensive improvement in high ionic conductivity, good mechanical properties, excellent thermal stability and interfacial compatibility.
[0044] This application also discloses a preparation method for preparing the following composite gel polymer electrolyte, including steps 110-150.
[0045] Step 110: Prepare hydroxylated polyvinylidene fluoride-hexafluoropropylene.
[0046] For example, the hydroxylation pretreatment of polyvinylidene fluoride-hexafluoropropylene includes: dissolving polyvinylidene fluoride-hexafluoropropylene in N,N-dimethylformamide, adding monoethanolamine, reacting at 80-100°C for 6-10 hours under nitrogen protection, and obtaining hydroxylated polyvinylidene fluoride-hexafluoropropylene by precipitation, washing, and drying.
[0047] Step 120 involves reacting the hydroxylated polyvinylidene fluoride-hexafluoropropylene with a nitrogen-containing heterocyclic silane modifier to obtain a modified polymer backbone.
[0048] In this application, the modified polymer skeleton can be understood as polyvinylidene fluoride-hexafluoropropylene modified with nitrogen-containing heterocyclic silane.
[0049] For example, the reaction of the hydroxylated polyvinylidene fluoride-hexafluoropropylene with a nitrogen-containing heterocyclic silane modifier includes: reacting the hydroxylated polyvinylidene fluoride-hexafluoropropylene with the nitrogen-containing heterocyclic silane modifier in anhydrous toluene at 70-90°C for 8-12 hours in the presence of the catalyst dibutyltin dilaurate. Alternatively, the reaction of the hydroxylated polyvinylidene fluoride-hexafluoropropylene with the nitrogen-containing heterocyclic silane modifier includes: dissolving the hydroxylated polyvinylidene fluoride-hexafluoropropylene in anhydrous toluene, adding the dibutyltin dilaurate catalyst, adding the nitrogen-containing heterocyclic silane modifier dropwise, reacting at 70-90°C for 8-12 hours, and obtaining nitrogen-containing heterocyclic silane-modified polyvinylidene fluoride-hexafluoropropylene after precipitation, washing, and drying.
[0050] Step 130: Prepare hydroxylated niobium oxide nanoparticles and perform surface functionalization modification on the hydroxylated niobium oxide nanoparticles to synthesize surface-functionalized hydroxylated niobium oxide nanoparticles.
[0051] For example, the preparation of hydroxylated niobium oxide nanoparticles includes: dispersing niobium oxide nanoparticles in deionized water to form a suspension, adjusting the pH to 1.5-2.5, reacting at 80-90℃ for 3-5 hours, and obtaining hydroxylated niobium oxide nanoparticles by centrifugation, washing, and drying.
[0052] An example of the synthesis of surface-functionalized hydroxylated niobium oxide nanoparticles includes: dispersing hydroxylated niobium oxide nanoparticles in anhydrous ethanol, adding silane coupling agent KH570, reacting at 60-70°C for 2-4 hours under nitrogen protection, and obtaining functionalized niobium oxide nanoparticles by centrifugation, washing, and drying.
[0053] Step 140: Under an inert atmosphere, the modified polymer backbone, the surface-functionalized hydroxylated nano-niobium oxide, organic solvent, lithium salt, crosslinking agent and initiator are mixed to prepare a prepolymer solution.
[0054] For example, the preparation of the prepolymer liquid includes: mixing the modified polymer backbone, the surface-functionalized hydroxylated nano-niobium oxide, an organic solvent, a lithium salt (LiTFSI), a crosslinking agent, and an initiator under an argon atmosphere, and then ultrasonically dispersing the mixture to obtain a uniform prepolymer liquid.
[0055] Step 150: The prepolymer liquid is subjected to in-situ polymerization and gelation to obtain the composite gel polymer electrolyte.
[0056] For example, the in-situ polymerization and gelation of the prepolymer liquid includes: in-situ polymerization of the prepolymer liquid at 50-60°C for 4-8 hours, followed by vacuum drying at 40-50°C for 12-20 hours to complete the gelation. Alternatively, the in-situ polymerization and gelation of the prepolymer liquid to obtain the composite gel polymer electrolyte includes: ultrasonically degassing the prepolymer liquid, placing it in a mold, polymerizing at 50-60°C for 4-8 hours, and then vacuum drying at 40-50°C for 12-20 hours to obtain the composite gel polymer electrolyte.
[0057] This application also discloses a supercapacitor, including the composite gel polymer electrolyte described above.
[0058] This application uses polyvinylidene fluoride-hexafluoropropylene as the basic polymer backbone. By introducing a nitrogen-containing heterocyclic silane modifier, polyvinylidene fluoride-hexafluoropropylene is grafted and modified. The high bond energy of the silicon-oxygen bond enhances the thermal and electrochemical stability of the electrolyte. Simultaneously, the heterocyclic nitrogen atoms can form a synergistic coordination effect with lithium ions, optimizing the ion transport channel. An innovative composite of hydroxylated nano-niobium oxide is used as an inorganic functional modifier. Its unique layered structure provides physical support to enhance mechanical strength, and the abundant hydroxyl groups on its surface can regulate the lithium-ion desolvation process and inhibit lithium dendrite growth. Furthermore, the high dielectric constant of niobium oxide reduces the electrolyte / electrode interface impedance, further improving interfacial compatibility, ultimately achieving high rate performance and long cycle life for the supercapacitor.
[0059] The following embodiments of this application disclose the specific implementation process and comparative process of the composite gel polymer electrolyte and its preparation method, and the supercapacitor. The specific implementation process and comparative process of this part include the exemplary embodiments 1 to 16 and comparative examples 1 and 2.
[0060] Example 1 includes the following steps S1-S7.
[0061] S1: The hydroxylation pretreatment of PVDF-HFP included: 5g of PVDF-HFP powder with a molecular weight of 40,000 was placed in a 250mL three-necked flask, and 50mL of N,N-dimethylformamide (DMF) was added as a solvent. The mixture was heated to 80℃ and stirred at 300r / min until completely dissolved, forming a 10% (w / w) PVDF-HFP solution. 10mL of excess monoethanolamine was added to the solution, and the mixture was heated to 100℃ and reacted for 8h under nitrogen protection. After the reaction was completed, the reaction solution was slowly poured into 200mL of excess deionized water and stirred until a white precipitate completely formed. The precipitate was collected by filtration and washed repeatedly with deionized water 5 times until the pH of the washing solution was 7. The precipitate was then dried in a vacuum drying oven at 60℃ for 12h to obtain hydroxylated PVDF-HFP, which was then transferred to a desiccator for cooling and later use.
[0062] S2: Synthesis of nitrogen-containing heterocyclic silane-modified PVDF-HFP, comprising: adding 4g of pretreated hydroxylated PVDF-HFP and 80mL of anhydrous toluene to a 250mL three-necked flask under nitrogen protection, heating to 70℃, and stirring at 300r / min until completely dissolved. Adding 0.02g of catalytic amount of dibutyltin dilaurate (DBTDL, 0.5% of the total mass of the reactants), followed by slowly adding 0.2g of nitrogen-containing heterocyclic silane modifier (N-(3-triethoxysilylpropyl)-4-methylpyridine bromide, 5% of the mass of hydroxylated PVDF-HFP) dropwise through a constant pressure dropping funnel at a dropping rate of 2 drops / second. After the addition is complete, heating to 90℃ and continuing the reaction for 10h. After the reaction was completed, the reaction solution was poured into 200 mL of excess anhydrous diethyl ether, stirred to precipitate, filtered and collected, and washed three times (50 mL each time) with anhydrous diethyl ether to remove unreacted silane modifier. The precipitate was then placed in a vacuum drying oven at 70 °C and dried for 8 h to obtain nitrogen-containing heterocyclic silane modified PVDF-HFP for later use.
[0063] S3: Preparation of hydroxylated nano-Nb2O5, including: placing 2g of commercially available nano-Nb2O5 powder in a 100mL beaker, adding 40mL of deionized water, and ultrasonically dispersing at 40kHz for 30 minutes to form a 5% (w / w) suspension. Adding concentrated nitric acid dropwise to the suspension to adjust the pH to 2, then transferring to a 250mL three-necked flask, and stirring at 250r / min for 4h at 80℃. After the reaction, centrifuging at 8000r / min for 10 minutes, collecting the precipitate, washing the precipitate four times with deionized water until the pH of the washing solution reaches 7, and then drying in a vacuum drying oven at 80℃ for 6h to obtain hydroxylated nano-Nb2O5 for later use.
[0064] S4: Synthesis of surface-functionalized modified nano-Nb2O5, including: placing 1g of hydroxylated nano-Nb2O5 powder in a 100mL three-necked flask, adding 50mL of anhydrous ethanol, and ultrasonically dispersing at 40kHz for 20 minutes to form a uniform suspension. Adding 0.05g of silane coupling agent KH570 (5% of the mass of nano-Nb2O5), and under nitrogen protection, heating to 65℃ and stirring at 250r / min for 3h. After the reaction, centrifuging at 8000r / min for 10 minutes, collecting the precipitate, washing three times with 30mL of anhydrous ethanol each time, and drying in a vacuum drying oven at 70℃ for 8h to obtain surface-functionalized modified nano-Nb2O5 for later use.
[0065] S5: Preparation of the prepolymer solution, including: In an argon-atmospheric glove box, add 2g of nitrogen-containing heterocyclic silane-modified PVDF-HFP (50% by mass) and 2mL of mixed organic solvent (propylene carbonate (PC) and diethyl carbonate (DEC) mixed at a volume ratio of 1:1, i.e., 1mL PC + 1mL DEC) to a 100mL Schlenk flask, and stir at 300r / min for 15 minutes. Add 0.35g of electrolyte lithium salt LiTFSI (1mol / L concentration), and continue stirring for 30 minutes until completely dissolved. Subsequently, 0.1 g of surface-functionalized modified nano-Nb2O5 (5% of the mass of modified PVDF-HFP) was added, and the mixture was ultrasonically dispersed at 40 kHz for 40 minutes. Then, 0.06 g of crosslinking agent EGDMA (3% of the mass of modified PVDF-HFP) and 0.02 g of initiator AIBN (1% of the mass of modified PVDF-HFP) were added, and the mixture was stirred for 10 minutes to obtain a uniform and stable prepolymer solution.
[0066] S6: In-situ polymerization and gelation, including: transferring the prepolymer solution into a polytetrafluoroethylene mold (50mm × 50mm × 0.1mm) with a sealing device, and ultrasonically degassing at 40kHz for 10 minutes to remove air bubbles. The mold is then placed in a 55℃ constant temperature water bath and reacted for 6 hours, allowing the double bonds in the modified PVDF-HFP to undergo free radical polymerization with the crosslinking agent EGDMA, forming a three-dimensional crosslinked network. After the reaction, the mold is transferred to a 45℃ vacuum drying oven and dried for 16 hours to remove residual organic solvents and unreacted small molecules, yielding a composite gel polymer electrolyte with uniform thickness.
[0067] S7: Supercapacitors are prepared in the following order: positive electrode shell, positive electrode sheet, gel polymer electrolyte, graphite sheet, stainless steel sheet, spring sheet, and negative electrode shell. The positive electrode is a composite material of lithium nickel cobalt manganese oxide and activated carbon, and the negative electrode is natural graphite.
[0068] Example 2: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 5% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 6% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=1:1 (volume ratio). The remaining steps and raw material amounts are completely consistent with Example 1.
[0069] Example 3: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 5% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 8% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=1:1 (volume ratio). The remaining steps and raw material amounts are completely consistent with Example 1.
[0070] Example 4: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 5% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 10% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=1:1 (volume ratio); the remaining steps and raw material amounts are completely consistent with Example 1.
[0071] Example 5: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 8% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 6% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=1:1 (volume ratio); the remaining steps and raw material amounts are completely consistent with Example 1.
[0072] Example 6: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 10% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 6% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=1:1 (volume ratio); the remaining steps and raw material amounts are completely consistent with Example 1.
[0073] Example 7: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 12% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 6% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=1:1 (volume ratio); the remaining steps and raw material amounts are completely consistent with Example 1.
[0074] Example 8: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 8% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 6% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=2:1 (volume ratio); the remaining steps and raw material amounts are completely consistent with Example 1.
[0075] Example 9: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 8% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 6% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=1:2 (volume ratio); the remaining steps and raw material amounts are completely consistent with Example 1.
[0076] Example 10: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 8% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 6% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=3:1 (volume ratio); the remaining steps and raw material amounts are completely consistent with Example 1.
[0077] Example 11: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 8% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 6% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=1:3 (volume ratio); the remaining steps and raw material amounts are completely consistent with Example 1.
[0078] Example 12: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 8% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 6% of the mass of modified PVDF-HFP, the mixed solvent PC:DEC=1:1 (volume ratio), the in-situ polymerization temperature is 60℃ and the time is 5h; the remaining steps and raw material amounts are completely consistent with Example 1.
[0079] Example 13: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 4% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 6% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=1:1 (volume ratio); the remaining steps and raw material amounts are completely consistent with Example 1.
[0080] Example 14: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 15% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 6% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=1:1 (volume ratio); the remaining steps and raw material amounts are completely consistent with Example 1.
[0081] Example 15: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 8% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 4% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=1:1 (volume ratio); the remaining steps and raw material amounts are completely consistent with Example 1.
[0082] Example 16: The difference between this example and Example 1 is that the amount of nitrogen-containing heterocyclic silane modifier is 8% of the mass of hydroxylated PVDF-HFP, the amount of nano Nb2O5 added is 12% of the mass of modified PVDF-HFP, and the mixed solvent PC:DEC=1:1 (volume ratio); the remaining steps and raw material amounts are completely consistent with Example 1.
[0083] Comparative Example 1: The difference between this comparative example and Example 1 is that the nitrogen-containing heterocyclic silane modifier was not used. Instead, a common silane modifier without nitrogen heterocycles, methyltrimethoxysilane, was used (the amount was the same as the nitrogen-containing heterocyclic silane in Example 1, i.e., 5% of the mass of hydroxylated PVDF-HFP). Other conditions were the same as in Example 1. The remaining steps and raw material amounts were completely the same as in Example 1.
[0084] Comparative Example 2: The difference between this comparative example and Example 1 is that no nano Nb2O5 was added, while the other conditions were the same as in Example 1; the remaining steps and raw material amounts were completely the same as in Example 1.
[0085] The gel polymer electrolytes prepared in Examples 1 to 16 and Comparative Examples 1 and 2 were subjected to performance tests. The test parameters included: the electrochemical window was determined by linear sweep voltammetry (LSV) at a scan rate of 1 mV / s and a voltage range of 0-6 V; the ionic conductivity was determined by AC impedance spectroscopy at a test frequency of 10 Hz. - ²-10 6 Hz, temperature 25℃; Cyclic stability was based on an assembled activated carbon / / composite gel electrolyte / / activated carbon supercapacitor, charged and discharged for 10,000 cycles at a current density of 1 A / g, and the capacity retention after cycling was calculated. Table 1 below shows the performance test results of the gel polymer electrolytes prepared in Examples 1 to 16 and Comparative Examples 1 and 2.
[0086] Table 1: Performance Test Results of Gel Polymer Electrolytes
[0087]
[0088] Combine Table 1 and Appendix Figure 2 As can be seen, the regulation of the amount of nano-Nb2O5 added can be summarized as follows: Combining the data from Examples 1-4 (5% fixed nitrogen-containing heterocyclic silane) and 15-16 (8% fixed nitrogen-containing heterocyclic silane), it can be seen that within the range of 4%-8% added nano-Nb2O5, the performance shows a significant upward trend with increasing addition amount. At an addition amount of 4% (Example 15), the room temperature ionic conductivity is 3.3 × 10⁻⁶. - ³ S / cm, tensile strength 2.4 MPa. Due to insufficient particle content, the layered physical support, hydroxyl ion regulation, and interface optimization effects were not fully utilized, resulting in performance weaker than Example 2 (2.6 × 10⁻⁶) with a 6% addition. - ³ S / cm, 2.9 MPa) and Example 5 (4.3 × 10 - The performance reached its peak at an addition of 8% (Example 3), with an ionic conductivity of 3.9 × 10⁻⁶ S / cm and a pressure of 3.1 MPa. - At a tensile strength of 3.3 MPa and a cycle retention rate of 95%, the particles are uniformly dispersed, and the synergistic effect is fully released. When the addition amount exceeds 8% (10%-12%), the performance gradually decreases. In Example 16 with a 12% addition amount, the room temperature ionic conductivity is only 1.9 × 10⁻⁶. -The concentration of nano-Nb₂O₅ was 3S / cm, with a cycle retention rate of 88%. Excessive particle aggregation disrupted ion transport channels and weakened the interfacial bonding with the polymer matrix. This validates the rationality of the 4%-12% nano-Nb₂O₅ addition range in the embodiments of this application; within this range, performance can be effectively improved by controlling particle dispersibility.
[0089] Combined with Table 1 and Appendix Figure 2 As can be seen from the data in Examples 2, 5-7 (6% fixed nano-Nb2O5), and 13-14 (6% fixed nano-Nb2O5), the performance of nitrogen-containing heterocyclic silanes continuously improves with increasing dosage within the range of 4%-10%. At a dosage of 4% (Example 13), the room temperature ionic conductivity is 3.1 × 10⁻⁶. - The performance of Example 2 (with a concentration of 3S / cm and an interfacial impedance of 4.1Ω) is lower than that of Example 2 (with a concentration of 5%) due to insufficient heterocyclic nitrogen atoms, which limits the coordination and conduction of lithium ions and results in an imperfect ion transport channel. Example 6 (with a concentration of 10%) exhibits the best performance, with a room temperature ionic conductivity of 4.6 × 10³ S / cm. - At 3 S / cm, tensile strength 3.4 MPa, and cycle retention 97%, the nitrogen atom coordination effect and the silicon-oxygen bond thermal stabilization effect reach the optimal balance. When the dosage exceeds 10% (12%-15%), the performance slightly decreases; in Example 14 with a 15% dosage, the room temperature ionic conductivity is 3.9 × 10⁻⁶. - ³ S / cm, due to the self-polymerization of excess silane, which hinders lithium ion migration, but still maintains good overall performance (thermal stability 95%, cycle retention 93%), proving the scientific validity of the 4%-15% dosage range of nitrogen-containing heterocyclic silanes. Within this range, the core functions of coordination conduction enhancement and silicon-oxygen thermal stabilization can be achieved.
[0090] Combined with Table 1 and Appendix Figure 2 As can be seen, the influence of the mixed solvent ratio is as follows: Data from Examples 5 and 8-11 (8% nitrogen-containing heterocyclic silane, 6% fixed nano-Nb2O5) show that the performance is optimal when the mixed solvent PC:DEC = 1:1 (Example 5: 4.3 × 10⁻⁶). - (³ S / cm); after deviating from this ratio, the performance gradually decreases with the increase of the deviation. When the PC ratio is too high (3:1, Example 10) or the DEC ratio is too high (1:3, Example 11), the room temperature ionic conductivity drops to 3.1 × 10⁻⁶ S / cm. - ³ S / cm, 2.9×10 -The cycle retention rate also decreased simultaneously, due to the imbalance in solvent ratio leading to decreased compatibility with the modified PVDF-HFP and weakened electrolyte retention capacity. However, even at the edge ratios of 1:3 or 3:1, the performance was still significantly better than the comparative examples (e.g., 89% cycle retention rate in Example 11 vs. 72% in Comparative Example 1), verifying the rationality of the solvent ratio range of 1:4-4:1 in the examples of this application. This range has good process tolerance and can be adapted to the needs of different production scenarios.
[0091] From the appendix Figure 3 It can be seen that the impedance of Examples 6 and 8 is significantly lower than that of Comparative Examples 1 and 2, which is mainly attributed to the increase in ionic conductivity.
[0092] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of this application, and this application is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this application, and these modifications and improvements are also considered to represent the scope of protection of this application.
Claims
1. A composite gel polymer electrolyte, characterized in that, include: A modified polymer backbone is prepared by condensation reaction of hydroxylated polyvinylidene fluoride-hexafluoropropylene and a nitrogen-containing heterocyclic silane modifier, wherein the nitrogen-containing heterocyclic silane modifier is N-(3-triethoxysilylpropyl)-4-methylpyridine bromide. Surface-functionalized hydroxylated niobium oxide nanoparticles dispersed in the modified polymer backbone, wherein the surface-functionalized hydroxylated niobium oxide nanoparticles are prepared by a condensation reaction of hydroxylated niobium oxide nanoparticles and methacryloxypropyltrimethoxysilane; Organic solvent and lithium salt impregnated in the modified polymer backbone, which is a three-dimensional network structure generated by a crosslinking agent.
2. The composite gel polymer electrolyte according to claim 1, characterized in that, The amount of nitrogen-containing heterocyclic silane modifier added is 4% to 15% of the mass of the hydroxylated polyvinylidene fluoride-hexafluoropropylene.
3. The composite gel polymer electrolyte according to claim 1, characterized in that, The amount of surface-functionalized hydroxylated nano-niobium oxide added is 4% to 12% of the mass of the modified polymer backbone.
4. The composite gel polymer electrolyte according to claim 1, characterized in that, The organic solvent is a mixture of propylene carbonate and diethyl carbonate, wherein the volume ratio of propylene carbonate to diethyl carbonate ranges from 1:4 to 4:
1.
5. A composite gel polymer electrolyte according to claim 1, characterized in that, The lithium salt is lithium bis(trifluoromethanesulfonyl)imide, and the concentration of lithium bis(trifluoromethanesulfonyl)imide in the composite gel polymer electrolyte is from 0.6 mol / L to 1.5 mol / L.
6. The composite gel polymer electrolyte according to claim 1, characterized in that, The crosslinking agent is ethylene glycol dimethacrylate, and the amount of ethylene glycol dimethacrylate added is 2% to 5% of the mass of the modified polymer backbone.
7. A preparation method for preparing a composite gel polymer electrolyte as described in any one of claims 1 to 6, characterized in that, include: Preparation of hydroxylated polyvinylidene fluoride-hexafluoropropylene; The hydroxylated polyvinylidene fluoride-hexafluoropropylene is reacted with a nitrogen-containing heterocyclic silane modifier to obtain a modified polymer backbone; Hydroxylated niobium oxide nanoparticles were prepared, and the hydroxylated niobium oxide nanoparticles were surface functionalized to synthesize surface-functionalized hydroxylated niobium oxide nanoparticles. Under an inert atmosphere, the modified polymer backbone, the surface-functionalized hydroxylated niobium oxide nanoparticles, an organic solvent, a lithium salt, a crosslinking agent, and an initiator are mixed to prepare a prepolymer solution. The prepolymer solution is subjected to in-situ polymerization and gelation to obtain the composite gel polymer electrolyte.
8. The preparation method according to claim 7, characterized in that, The reaction of the hydroxylated polyvinylidene fluoride-hexafluoropropylene with a nitrogen-containing heterocyclic silane modifier includes: In the presence of the catalyst dibutyltin dilaurate, the hydroxylated polyvinylidene fluoride-hexafluoropropylene and the nitrogen-containing heterocyclic silane modifier are reacted in anhydrous toluene at 70-90°C for 8-12 hours.
9. The preparation method according to claim 7, characterized in that, The in-situ polymerization and gelation of the prepolymer liquid includes: The prepolymer solution is polymerized in situ at 50-60°C for 4-8 hours, and then vacuum dried at 40-50°C for 12-20 hours to complete the gelation.
10. A supercapacitor, characterized in that, Includes a composite gel polymer electrolyte as described in any one of claims 1 to 6.