All-weather mxene co-crystal protein gel electrolyte and preparation method thereof, supercapacitor

Abstract

The application discloses a kind of all-weather MXene eutectic protein gel electrolyte and preparation method thereof, and supercapacitor.The preparation method comprises: mixing MXene solution with protein gel, obtaining homogeneous mixed solution by ultrasonic treatment and heating stirring;Homogeneous mixed solution is gelled at 4-6 ℃ for 3-6 hours, and the coagulation state MXene protein gel is obtained;Choline-based compound and polyol are used to prepare deep eutectic solution;Coagulation state MXene protein gel is soaked in deep eutectic solution until free water and deep eutectic solution reach exchange equilibrium, and MXene eutectic protein gel electrolyte is obtained.The application constructs wide temperature range ion transport channel by solvent exchange strategy, and forms three-dimensional conductive network by in-situ dispersion of MXene.The prepared electrolyte can maintain stable ionic conductivity and mechanical properties in the temperature range of-20 ℃ to 40 ℃, and is suitable for all-weather supercapacitor.

Description

Technical Field

[0001] This invention belongs to the field of flexible energy storage materials technology, specifically relating to an all-weather MXene cocrystal protein gel electrolyte and its preparation method, and a supercapacitor. Background Technology

[0002] With the increasing demand for flexible wearable electronic devices, the development of high-performance energy storage devices has become an important research direction. Protein-based gels are a class of gel materials formed by solvent embedding in a three-dimensional polymer network. They possess good biocompatibility, tunable degradability, sustainability, and abundant functionalization sites, and have application potential in tissue engineering, biosensing, and flexible energy storage.

[0003] However, existing protein gels are mostly composed of disordered protein chains with relatively loose cross-linked networks, often exhibiting problems such as low stiffness, limited strength, and insufficient toughness, which restricts their application in flexible energy storage devices. Meanwhile, wearable electronic devices operating in extreme environments place higher demands on the wide-temperature stability of energy storage systems. Traditional aqueous or polymer electrolytes are prone to freezing or glass transition at low temperatures, inhibiting ion diffusion and reducing ionic conductivity; at high temperatures, they may lose water, soften, or become structurally unstable, leading to device performance degradation and shortened lifespan. Therefore, developing gel electrolyte materials that combine mechanical reliability with wide-temperature electrochemical stability remains a key challenge for next-generation flexible energy storage devices.

[0004] Deep eutectic solvents (DES) offer a novel approach to constructing wide-temperature-tolerant gel systems. Compared to traditional hydrogels, DES-based cosolvent gels typically exhibit stronger evaporation resistance, better thermal and electrochemical stability, and superior environmental tolerance. However, due to the unique physicochemical properties of DES, traditional protein gel enhancement strategies may not be applicable in cocrystalline systems, and the resulting cocrystalline protein gels may still suffer from insufficient mechanical properties and poor toughness. By designing DES rich in polyols, the hydroxyl groups in the polyols can form hydrogen bond networks with functional groups such as -OH, -O-, and -NH2 on the protein chains, thereby enhancing interchain interactions and improving the compatibility between proteins and solvents.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, this invention provides an all-weather MXene cocrystal protein gel electrolyte, its preparation method, and a supercapacitor. The technical problem to be solved by this invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing an all-weather MXene cocrystal protein gel electrolyte, comprising the following steps: S1. Mix the MXene solution with the protein gel, and then sequentially sonicate and heat and stir to obtain a homogeneous mixed solution; S2. The homogeneous mixed solution is transferred to a molding mold and gelled at 4-6°C for 3-6 hours to obtain a solidified MXene protein gel. S3. Deep eutectic solutions are prepared using choline compounds and polyols; S4. Immerse the MXene protein gel in the deep eutectic solution until the free water of the MXene protein gel and the deep eutectic solution reach exchange equilibrium to obtain the MXene eutectic protein gel electrolyte.

[0008] In one embodiment of the present invention, in step S1, the MXene solution is Ti3C2T. x MXene solution, the Ti3C2T x Ti3C2T in MXene solution x The concentration of MXene is 3–5 mg / mL; the protein gel is gelatin. The Ti3C2T x The mass ratio of MXene solution to gelatin is 10:(0.8-1.0).

[0009] In one embodiment of the present invention, the Ti3C2T x The preparation process of MXene solution includes: S11. Titanium powder, aluminum powder and titanium carbide powder are mixed in a molar ratio of 1:1.2:2, ball-milled and sintered in an argon atmosphere at 1300-1500℃, and then ground to obtain Ti3AlC2MAX phase powder. S12. Add Ti3AlC2MAX phase powder to an etching solution composed of LiF and HCl, and stir and react at 40-45°C for 24-48 hours. S13. After washing the reaction product to neutral pH, the supernatant was collected by sonication in an ice bath and centrifugation to obtain Ti3C2T. x MXene solution.

[0010] In one embodiment of the present invention, in step S1, the conditions for ultrasonic treatment are: ultrasonic power of 90-120 W and ultrasonic time of 20-30 minutes. The heating and stirring conditions are as follows: the heating temperature is 50-70 ℃, and the heating and stirring time is 1-3 hours.

[0011] In one embodiment of the present invention, in step S2, the molding die includes a first tempered glass plate and a second tempered glass plate stacked together; An array of silicone spacers is provided between the first tempered glass plate and the second tempered glass plate; the thickness of the silicone spacers is 1 to 1.5 mm along a direction that is perpendicular to both the first and second tempered glass plates.

[0012] In one embodiment of the present invention, in step S3, the choline compound is choline chloride, and the polyol is 1,3-propanediol; Step S3 includes: obtaining choline chloride and 1,3-propanediol; A deep eutectic solution is obtained by mixing choline chloride and 1,3-propanediol in a molar ratio of 1:(1-6), heating the mixture to 80-85 °C, and reacting for 2-3 hours.

[0013] In one embodiment of the present invention, step S4 includes: immersing the MXene protein gel in the deep eutectic solution at 15-30°C for 12-24 hours to obtain the MXene eutectic protein gel electrolyte.

[0014] Secondly, the present invention provides an all-weather MXene cocrystal protein gel electrolyte, which is obtained by the above preparation method.

[0015] Thirdly, the present invention provides a symmetrical supercapacitor, including a positive electrode, a negative electrode, and an electrolyte disposed between the positive electrode and the negative electrode, wherein the electrolyte is the above-mentioned all-weather MXene cocrystal protein gel electrolyte.

[0016] In one embodiment of the present invention, the application environment temperature of the symmetrical supercapacitor is -20 ℃ to 40 ℃.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention first mixes MXene with protein gel to form a homogeneous solution, then gels it to obtain a solidified MXene protein gel, and finally immerses it in a deep eutectic solution to complete the exchange of free water and deep eutectic solvent. This method, through two-step solvent exchange, enables the three-dimensional protein network to synergistically interact with the polyol DES, preserving the hydrogen bond crosslinks between protein chains while introducing a new hydrogen bond network between the polyol and the functional groups on the protein chains, forming a continuous dual ion transport channel, ensuring rapid ion migration over a wide temperature range.

[0018] 2. The MXene cocrystal protein gel electrolyte prepared by this invention maintains stable ionic conductivity and mechanical properties within a temperature range of -20℃ to 40℃, meeting the requirements for use under all climatic conditions. This electrolyte can be applied to symmetrical supercapacitors, providing stable energy storage performance over a wide temperature range, solving the problem of performance degradation of traditional electrolytes at extreme temperatures, and providing a solution for the application of flexible wearable electronic devices in complex environments.

[0019] 3. This invention employs low-temperature gelation at 4–6°C. Under this temperature condition, the thermal motion of the protein chains is inhibited, and the gelation process proceeds smoothly, forming a uniform and dense three-dimensional network. The subsequent deep eutectic solution immersion process is carried out at 15–30°C, which ensures sufficient solvent exchange and avoids damage to the protein network structure caused by high temperature. This results in the final MXene eutectic protein gel electrolyte having good mechanical strength and toughness, and being able to withstand a certain degree of bending and compression deformation.

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating a method for preparing an all-weather MXene cocrystal protein gel electrolyte according to an embodiment of the present invention; Figure 2 These are the FT-IR and Raman spectra characterization diagrams of the MXene cocrystal protein gel electrolytes prepared in Examples 1, 2 and Comparative Example 1 of this invention; Figure 3 This is a schematic diagram showing the water retention (a) and (b) and self-healing (c) test results of the MXene cocrystal protein gel electrolyte prepared in Example 1 of the present invention and the MXene protein gel prepared in Comparative Example 1. Figure 4 This is a schematic diagram showing the melting test results of the MXene cocrystal protein gel electrolyte prepared in Example 1 of this invention at a high temperature of 40°C and a tensile antifreeze test results at a low temperature of -20°C. Figure 5 This is a schematic diagram of the cyclic voltammetry (a), constant current charge-discharge (b), and impedance diagram (b) of the MXene cocrystal protein gel electrolyte prepared in Example 1 of this invention at -20°C to 40°C. Figure 6 This is a schematic diagram of the cycling performance and coulombic efficiency of the MXene cocrystal protein gel electrolyte prepared in Example 1 of this invention at -20°C to 40°C. Detailed Implementation

[0022] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following, in conjunction with the accompanying drawings and specific embodiments, provides a detailed description of an all-weather MXene cocrystal protein gel electrolyte, its preparation method, and a supercapacitor proposed according to the present invention.

[0023] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of specific embodiments in conjunction with the accompanying drawings. Through the description of the specific embodiments, a more in-depth and concrete understanding can be gained of the technical means and effects adopted by the present invention to achieve its intended purpose. However, the accompanying drawings are for reference and illustration only and are not intended to limit the technical solutions of the present invention.

[0024] It should be noted that, in this document, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed.

[0025] Protein-based gels possess excellent biocompatibility, tunable degradability, sustainability, and abundant functionalization sites. However, existing protein gels often suffer from loose cross-linked networks and insufficient mechanical properties. Furthermore, in extreme environments, traditional protein gels are prone to freezing at low temperatures or softening and melting at high temperatures. Therefore, developing protein gel electrolyte materials that combine excellent mechanical properties with wide-temperature electrochemical stability is of great significance.

[0026] This invention provides a method for preparing an all-weather MXene cocrystal protein gel electrolyte, see [link to relevant documentation]. Figure 1 This includes the following steps: S1. Mix the MXene solution with the protein gel, and then sequentially sonicate and heat and stir to obtain a homogeneous mixed solution.

[0027] In some examples, the MXene solution is Ti3C2T x MXene solution, Ti3C2T x Ti3C2T in MXene solution x The concentration of MXene is 3–5 mg / mL; the protein gel is gelatin.

[0028] For example, Ti3C2T xThe mass ratio of MXene solution to gelatin is 10:(0.8–1.0). That is, for every 10 parts by mass of Ti3C2Tx MXene solution, there are 0.8 to 1.0 parts by mass of gelatin. This ratio range ensures uniform dispersion of MXene in the protein gel, while also ensuring good mechanical strength of the three-dimensional network structure formed after gelation. Gelatin dissolves in the MXene solution under heating conditions. Too little gelatin (<0.8 parts) will result in overly soft synthesized gelatin, while too much gelatin (>1 part) will significantly increase the overall viscosity.

[0029] Furthermore, Ti3C2T x The mass ratio of MXene solution to gelatin is 10:(0.8-1.0). Preferably, it is Ti3C2T. x The mass ratio of MXene solution to gelatin is 10:1.

[0030] In one example, Ti3C2T x The preparation process of MXene solution includes: S11, mixing titanium powder, aluminum powder, and titanium carbide powder in a molar ratio of 1:1.2:2, ball milling, and sintering in an argon atmosphere at 1300–1500℃ to obtain Ti3AlC2MAX phase powder. S12, adding the Ti3AlC2MAX phase powder to an etching solution composed of LiF and HCl, and stirring the reaction at 40–45℃ for 24–48 hours. S13, washing the reaction product until the pH is neutral, and then sonicating and centrifuging in an ice bath to obtain Ti3C2T. x MXene solution. This preparation method can obtain monolayer or few-layer Ti3C2T x MXene nanosheets have abundant functional groups such as -O, -OH and -F on their surface, which provide active sites for subsequent chemical interactions with protein chains.

[0031] For example, in step S1, after mixing the MXene solution with the protein gel, the ultrasonic treatment conditions are: ultrasonic power of 90–120 W and ultrasonic time of 20–30 minutes, so that the Ti3C2Tx MXene sheets are uniformly dispersed in the protein gel, avoiding the stacking and aggregation of the sheets. The heating and stirring conditions are: heating temperature of 50–70 °C and heating and stirring time of 1–3 hours, so that the gelatin fully swells in the MXene solution and forms a uniform mixture system.

[0032] S2. Transfer the homogeneous mixed solution to a molding die and gel at 4–6°C for 3–6 hours to obtain a solidified MXene protein gel. Gelation at low temperatures inhibits the thermal motion of protein chains, allowing for a smooth gelation process and the formation of a uniform and dense three-dimensional network structure.

[0033] For example, the molding die includes a first tempered glass plate and a second tempered glass plate stacked together; an array of silicone spacers is disposed between the first and second tempered glass plates; the thickness of the silicone spacers is 1–1.5 mm along a direction perpendicular to both the first and second tempered glass plates. Thus, the prepared MXene protein gel has a thickness of 1–1.5 mm. The silicone spacers are arranged in an array to ensure uniform gel thickness throughout. The first and second tempered glass plates are made of tempered glass, which has good flatness and transparency, facilitating observation of the gelation process; simultaneously, the smooth surface of the tempered glass facilitates gel demolding.

[0034] S3. A deep eutectic solution is prepared using choline compounds and polyols.

[0035] In one example, the choline compound is choline chloride, and the polyol is 1,3-propanediol. Step S3 thus includes: obtaining choline chloride and 1,3-propanediol; mixing choline chloride and 1,3-propanediol in a molar ratio of 1:(1–6), heating to 80–85 °C, and reacting for 2–3 hours to obtain a deep eutectic solution.

[0036] The molar ratio of choline chloride to 1,3-propanediol in the eutectic solution is 1:(1-6). Choline chloride / 1,3-propanediol acts as the hydrogen bond acceptor and hydrogen bond donor, respectively, in the deep eutectic solution. The molar ratio affects the eutectic system's ability to form hydrogen bonds and its ion transport performance: when the proportion of hydrogen bond donors is too low, there are insufficient sites for hydrogen bond formation in the system, and the strong interactions dominated by ionic components will maintain the system viscosity at a high level, reducing the ion transport capacity; when the proportion of hydrogen bond donors is too high, the eutectic solution may be over-diluted, destroying the original ordered structure and even leading to long-range phase separation, affecting the system's stability. Therefore, the above-mentioned ratio range can achieve low viscosity and high ion transport capacity while ensuring stability. Furthermore, the molar ratio of choline chloride to 1,3-propanediol is 1:4.

[0037] S4. Immerse the MXene protein gel in a deep eutectic solution until the free water of the MXene protein gel and the deep eutectic solution reach an exchange equilibrium to obtain the MXene eutectic protein gel electrolyte.

[0038] Specifically, step S4 includes: immersing the MXene protein gel in a deep eutectic solution at 15–30°C for 12–24 hours to obtain the MXene eutectic protein gel electrolyte. During the immersion process, solvent exchange occurs between the free water in the MXene protein gel and the deep eutectic solution. The deep eutectic solution gradually penetrates into the gel, while the free water in the gel is gradually released into the deep eutectic solution. After 12–24 hours of immersion, the free water and the deep eutectic solution reach exchange equilibrium. At this point, the solvent system inside the gel changes from the original water-based system to a deep eutectic solvent-based system, forming the MXene eutectic protein gel electrolyte.

[0039] It should be noted that the preparation of the solidified MXene protein gel and the deep eutectic solution can be performed in any order. The deep eutectic solution can be prepared first, followed by the solidified MXene protein gel, or they can be performed simultaneously.

[0040] This invention provides a method for preparing an all-weather MXene cocrystal protein gel electrolyte. By introducing DES (deep eutectic solution) and MXene into a protein gel network, the choline compounds / polyol components in the DES and the surface functional groups of MXene can form multiple non-covalent interactions with the protein gel chains, constructing a stable hydrogen bond network and improving the mechanical brittleness and solvent retention of the protein gel. Simultaneously, this cocrystal gel electrolyte exhibits good water retention, self-healing properties, low-temperature freeze resistance, and high-temperature morphological stability. Furthermore, the preparation process of this invention is relatively simple, reproducible, and uses readily available raw materials, making it suitable for further development of gel-based supercapacitor electrolyte materials.

[0041] The formation and application mechanism of the MXene cocrystal protein gel electrolyte prepared by the method provided in this invention is as follows: The three-dimensional protein network is a three-dimensional network structure formed by the cross-linking of gelatin molecular chains through hydrogen bonds, which provides ion transport channels. MXene sheets are uniformly dispersed in the three-dimensional protein gel network, and the MXene sheets act as physical cross-linking points in the network backbone formed by the gel chains, enhancing the mechanical strength of the gel. At the same time, the MXene sheets have excellent conductivity, and their layered structure provides electron transport paths. The deep eutectic solvent fills the pores of the three-dimensional protein network and provides a medium for ion migration. A synergistic effect is formed between the gel network and the deep eutectic solvent through hydrogen bonding, which not only retains the cross-linked network of the gel itself, but also forms a new hydrogen bond network through the introduction of the deep eutectic solvent, further enhancing the ion transport capacity.

[0042] This invention also provides an all-weather MXene cocrystal protein gel electrolyte obtained by the above preparation method. This electrolyte maintains stable ionic conductivity and mechanical properties within a temperature range of -20°C to 40°C, meeting the requirements for use under all-weather conditions.

[0043] The all-weather MXene cocrystal protein gel electrolyte provided in this invention can be used to prepare supercapacitors, which include a positive electrode, a negative electrode, and an all-weather MXene cocrystal protein gel electrolyte disposed between the positive and negative electrodes. MXene helps improve the gel network and electrode / electrolyte interface transport; the introduced deep eutectic solution can provide ion migration channels, lower the freezing point, and inhibit high-temperature melting of the protein gel, thereby promoting interfacial bonding between the electrolyte and the electrode and extending the device's lifespan.

[0044] In some feasible embodiments, the operating temperature range of this symmetrical supercapacitor is -20 °C to 40 °C. This MXene eutectic protein gel electrolyte utilizes the low freezing point and low volatility of the deep eutectic solution, combined with the interfacial modulation effect of MXene, to improve upon the shortcomings of traditional protein gels, such as insufficient mechanical strength, limited ion conductivity, and susceptibility to freezing at low temperatures and melting at high temperatures. This enables the supercapacitor device to operate in extreme environments ranging from -20 °C to 40 °C. For example, the loading of the active material (activated carbon as the active material coated on the current collector to prepare symmetrical positive and negative electrodes) for the positive and negative electrodes is 3–5 mg.

[0045] The preparation method and performance of the MXene cocrystal protein gel electrolyte provided by the present invention are further illustrated below with reference to specific embodiments.

[0046] Example 1 S1, Ti3C2T x MXene solution and gelatin were mixed at a mass ratio of 10:1, ultrasonicated at 100W for 30 min, and then heated and stirred at 60℃ for 2 hours to form a homogeneous mixed solution; wherein, Ti3C2T x The concentration of MXene was 4 mg / mL.

[0047] S2. Transfer the homogeneous mixed solution to a molding mold and gel at 4-6°C for 4 hours to obtain MXene protein gel.

[0048] S3. Mix choline chloride and 1,3-propanediol in a molar ratio of 1:4 and stir for 3 hours under water bath heating at 80°C until a transparent and homogeneous deep eutectic solution is formed.

[0049] S4. At room temperature (15-30°C), the obtained MXene protein gel is immersed in a deep eutectic solution for 20 hours until solvent exchange equilibrium is reached to obtain MXene eutectic protein gel electrolyte. The electrolyte prepared in Example 1 is defined as GMD4.

[0050] Example 2 The difference between Example 2 and Example 1 is that in step S3, the molar ratio of choline chloride to 1,3-propanediol is adjusted to 1:3; the remaining operations are the same as in Example 1. The gel electrolyte prepared in Example 2 is defined as GMD3.

[0051] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that only steps S1 and S2 are performed, that is, Ti3C2T is used. x MXene solution and gelatin are mixed and gelatinized in a molding die to form a solidified MXene protein gel. Steps S3 and S4 are excluded. The MXene protein gel prepared in Comparative Example 1 is defined as GM.

[0052] Performance testing and results analysis: 1. See Figure 2 The physical properties of the gel electrolytes prepared in Examples 1, 2, and 1 (Comparative Example 1) were characterized. Figure 2 As shown in (a), the Fourier transform infrared (FT-IR) spectroscopy results show that, compared with the MXene protein gel alone in Comparative Example 1, both GMD3 and GMD4 exhibit a blue shift; the amide I peak of GMD4 shifts from 1635 cm⁻¹. -1 Moved to 1652 cm -1 This indicates enhanced interchain interactions and a redistribution of hydrogen bonds. Raman testing, as shown... Figure 2 As shown in (b), Raman deconvolution reveals more pronounced CH stretching bands in GMD3 and GMD4 compared to GM, consistent with increased alkyl contributions from the deep eutectic solvent (DES). Simultaneously, the amide A band broadens and exhibits a blue shift, indicating enhanced intermolecular hydrogen bonding between the gelatin chains and DES, consistent with FT-IR observations. Figure 2 The results show that DES can effectively modulate the internal hydrogen bond network and reconstruct the interactions within the gel.

[0053] 2. To assess environmental durability, a systematic drying test was conducted on GM and GMD4 at 25°C and 30% relative humidity. See [link / reference] Figure 3 As shown in (a), the GMD4 sample of Example 1 retained 95.17% water after 350 hours and remained soft and mechanically sound after 720 hours, with a water retention rate of 92.36%. For comparison, see [reference needed]. Figure 3As shown in Figure (b), the GM sample of Comparative Example 1 significantly lost water and hardened within approximately 72 hours, becoming brittle and losing its function. The excellent dehydration stability of the GMD4 sample is mainly attributed to the strong hydration capacity of choline chloride (ChCl), which can form stable interactions with water molecules, thereby inhibiting water evaporation; at the same time, the low volatility and good solvation ability of DES help maintain a stable microenvironment. Thus, GMD4 exhibits good long-term durability under harsh conditions.

[0054] like Figure 3 Image (c) shows the self-healing test. For ease of observation, the self-healing test sample consists of two parts: one part is GMD4 (black) prepared according to the method provided in Example 1, and the other part is GMD4' (light yellow). The difference between GMD4' and GMD4 is that in step S1 of Example 1, GMD4' does not contain Ti3C2T. x MXene solution. After cutting between the two colors, connect the cut surfaces. Figure 3 As can be seen, the two parts of the GMD4 sample reconnected after being cut. The self-healing test of the GMD4 sample shows that due to the dynamic hydrogen bond interactions inside the GMD4 electrolyte, the interface can be observed to reconnect after the cut surfaces come into contact again.

[0055] 3. Performance testing at different temperatures: For physically cross-linked gelatin-based gel electrolytes, high temperatures weaken the intermolecular interactions that maintain the network structure, leading to rapid softening, structural collapse, and even melting of the electrolyte. Therefore, 40°C is a harsh thermal environment for traditional gelatin electrolytes, rather than a gentle heat treatment. Figure 4 As shown in Figure (a), under conditions of 40 °C and 25% relative humidity, the original GM sample rapidly softened and melted within 10 minutes, losing its original shape; while the GMD4 electrolyte containing DES remained intact even after 12 hours, without significant melting or collapse, and maintained its initial shape. This indicates that the incorporation of DES can effectively suppress heat-induced instability of the gelatin network structure, thereby broadening the actual operating temperature window of the gelatin-based electrolyte.

[0056] GMD4 maintains good toughness and structural integrity even at low temperatures. Traditional gels typically harden and become brittle after freezing at -20°C. For example... Figure 4 Figure (b) shows the tensile and torsional states of GMD4 samples at -20°C, indicating that the GMD4 prepared in Example 1 maintains its transparency and mechanical integrity at -20°C and can be stretched and torsioned without breaking.

[0057] 4. See Figure 5Cyclic voltammetry, constant current charge-discharge, and impedance diagrams of the supercapacitor electrochemical device assembled from the MXene cocrystal protein gel electrolyte prepared in Example 1 at -20°C, 25°C, and 40°C.

[0058] To further evaluate the effectiveness of the assembled device under different temperature conditions, temperature-dependent electrochemical measurements were performed. Figure 5 As shown in (a), the area under the cyclic voltammetry (CV) curve gradually increases. This phenomenon can be attributed to the decrease in electrolyte viscosity, the reduction in ion transport resistance, and the decrease in activation energy, all of which collectively accelerate ion transport kinetics. Figure 5 As shown in (b), the device maintains excellent capacitance performance at temperatures of -20 °C, 25 °C, and 40 °C. At 1 A g -1 At current densities, the specific capacitances are 46 F g. -1 67 F g -1 and 79 F g -1 Furthermore, the reconstructed hydrogen bond network significantly improved the electrochemical stability of the supercapacitor device assembled with GMD4 electrolyte in the temperature range of -20 to 40 °C. Electrochemical impedance spectroscopy (EIS) further confirmed that the electrochemical transport capability significantly increased with increasing temperature. Figure 5 (b)

[0059] 5. See Figure 6 In (a), a supercapacitor device prepared using GMD4 electrolyte was tested at 25 °C and 2 A g. -1 At the specified current density, the device retains 95.83% of its initial capacity after 30,000 charge-discharge cycles, with a coulombic efficiency approaching 100%. The GCD (constant current charge-discharge) curves before and after cycling largely overlap, indicating that the device using GMD4 exhibits high electrochemical reversibility and capacitive stability. The stable hydrogen bond network in GMD4 helps suppress side reactions and maintain the integrity of the electrode / electrolyte interface. See also... Figure 6 As shown in Figure (b), after 3500 charge-discharge cycles at 40 °C, the capacitance retention of the GMD4 device remains at 84%; after 6000 cycles at -20 °C, the capacitance retention remains at 100%, and the coulombic efficiency remains stable at approximately 100%. These results demonstrate that the GMD4 electrolyte can prevent the structural collapse of the gelatin network and broaden the application scope of protein gels in the field of solid-state energy storage.

[0060] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an all-weather MXene cocrystal protein gel electrolyte, characterized in that, Includes the following steps: S1. Mix the MXene solution with the protein gel, and then sequentially sonicate and heat and stir to obtain a homogeneous mixed solution; S2. The homogeneous mixed solution is transferred to a molding mold and gelled at 4-6°C for 3-6 hours to obtain a solidified MXene protein gel. S3. Deep eutectic solutions are prepared using choline compounds and polyols; S4. Immerse the MXene protein gel in the deep eutectic solution until the free water of the MXene protein gel and the deep eutectic solution reach exchange equilibrium to obtain the MXene eutectic protein gel electrolyte.

2. The method for preparing the all-weather MXene cocrystal protein gel electrolyte according to claim 1, characterized in that, In step S1, the MXene solution is Ti3C2T. x MXene solution, the Ti3C2T x Ti3C2T in MXene solution x The concentration of MXene is 3–5 mg / mL; the protein gel is gelatin. The Ti3C2T x The mass ratio of MXene solution to gelatin is 10:(0.8-1.0).

3. The method for preparing the all-weather MXene cocrystal protein gel electrolyte according to claim 2, characterized in that, The Ti3C2T x The preparation process of MXene solution includes: S11. Titanium powder, aluminum powder and titanium carbide powder are mixed in a molar ratio of 1:1.2:2, ball-milled and sintered in an argon atmosphere at 1300-1500℃, and then ground to obtain Ti3AlC2MAX phase powder. S12. Add Ti3AlC2MAX phase powder to an etching solution composed of LiF and HCl, and stir and react at 40-45°C for 24-48 hours. S13. After washing the reaction product to neutral pH, the supernatant was collected by sonication in an ice bath and centrifugation to obtain Ti3C2T. x MXene solution.

4. The method for preparing the all-weather MXene cocrystal protein gel electrolyte according to claim 3, characterized in that, In step S1, the conditions for ultrasonic treatment are: ultrasonic power of 90-120 W and ultrasonic time of 20-30 minutes. The heating and stirring conditions are as follows: the heating temperature is 50-70 ℃, and the heating and stirring time is 1-3 hours.

5. The method for preparing the all-weather MXene cocrystal protein gel electrolyte according to claim 1, characterized in that, In step S2, the molding die includes a first tempered glass plate and a second tempered glass plate stacked together. An array of silicone spacers is provided between the first tempered glass plate and the second tempered glass plate; the thickness of the silicone spacers is 1 to 1.5 mm along a direction that is perpendicular to both the first and second tempered glass plates.

6. The method for preparing the all-weather MXene cocrystal protein gel electrolyte according to any one of claims 1-5, characterized in that, In step S3, the choline compound is choline chloride, and the polyol is 1,3-propanediol; Step S3 includes: obtaining choline chloride and 1,3-propanediol; A deep eutectic solution is obtained by mixing choline chloride and 1,3-propanediol in a molar ratio of 1:(1-6), heating the mixture to 80-85°C, and reacting for 2-3 hours.

7. The method for preparing the all-weather MXene cocrystal protein gel electrolyte according to claim 6, characterized in that, Step S4 includes: immersing the MXene protein gel in the deep eutectic solution at 15–30°C for 12–24 hours to obtain the MXene eutectic protein gel electrolyte.

8. A weather-resistant MXene cocrystal protein gel electrolyte, characterized in that, It is obtained by the preparation method described in any one of claims 1-7.

9. A symmetrical supercapacitor, comprising a positive electrode, a negative electrode, and an electrolyte disposed between the positive electrode and the negative electrode, characterized in that, The electrolyte is the all-weather MXene cocrystal protein gel electrolyte as described in claim 8.

10. The symmetrical supercapacitor according to claim 9, characterized in that, The symmetrical supercapacitor is designed for use in environments with temperatures ranging from -20°C to 40°C.

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