A high-strength and high-toughness ion-conducting composite material based on biomass interface modification, a preparation method and a flexible power device

Abstract

This invention relates to the field of functional polymer materials technology, and discloses a high-strength and tough ion-conducting composite material based on biomass interface modification, its preparation method, and a flexible power device. By forcibly introducing hydroxyethyl cellulose into the micropores and deep layers of the cell walls of a natural porous biomass framework, continuous nano-ion transport channels are constructed. Through an externally driven cross-scale interface construction method, a natural porous biomass framework / hydroxyethyl cellulose / polyacrylamide composite gel material with high strength, toughness, and high ion conductivity is prepared. The flexible moisture-activated power device assembled based on this material can achieve continuous construction of cross-scale ion channels while retaining the strength of the natural framework, thereby improving power generation performance and mechanical strength. The power density is approximately 20 times higher than that of pure hydrogels, and it can be applied to various scenarios such as hydrovoltaic power generation, moisture power generation, and metal-air batteries.

Description

Technical Field

[0001] This invention relates to the field of functional polymer materials technology, specifically to a high-strength and tough ion-conducting composite material based on biomass interface modification, its preparation method, and a flexible power supply device. Background Technology

[0002] With the rapid development of flexible wearable electronic devices and green Internet of Things (IoT) technologies, the development of environmentally friendly, biodegradable, and high-performance power systems has become a current research hotspot. Among these, the construction of moisture-activated power sources or flexible metal-air batteries using the three-dimensional porous structures of natural biomass materials (such as wood, loofah, and cellulose) has attracted widespread attention due to its low cost and controllable structure. Natural loofah (LS), as a unique mesh-like fibrous biomass, possesses excellent mechanical strength and natural flow channels, making it an ideal scaffold material for constructing such devices.

[0003] However, in practical applications, flexible power devices based on natural loofah still face several technical bottlenecks. First, there is the limitation on electrochemical performance due to interface incompatibility. The surface of natural loofah fibers typically contains a large amount of lignin and wax, exhibiting a certain degree of hydrophobicity. When combined with hydrophilic conductive hydrogel electrolytes, it is difficult to form a tight molecular-level contact, often resulting in numerous gas-liquid-solid interface dead zones within the micropores. This interface defect not only blocks the continuous ion transport channels, leading to a significant increase in device internal resistance, but also limits the device's open-circuit voltage (current reports typically show it to be below 1.5V) and output power density. Second, existing modification processes have limitations. To improve interface performance, existing technologies mainly employ two strategies, but both have drawbacks. Chemical grafting (such as in-situ growth of conductive polymers) offers better bonding, but the process is usually cumbersome, requiring the use of strong acids and alkalis or toxic organic solvents (such as aniline and pyrrole monomers). Furthermore, chemical reactions often damage the intrinsic mechanical strength of biomass fibers, leading to a brittle skeleton, which contradicts the principles of green manufacturing. Simple physical filling methods (such as immersion coating) are currently commonly used. However, simple natural immersion cannot overcome the capillary resistance of micropores, and functional materials can only adhere to the surface of the macroscopic framework, unable to penetrate into the micron / nanoscale cell walls. The resulting composite materials have weak interfacial bonding, and when the device is subjected to bending or tensile deformation, the conductive layer easily peels off from the framework, leading to voltage drop or device failure. Thirdly, there is a lack of cross-scale structural design. Existing research mainly focuses on the utilization of macroscopic structures, lacking in-depth development of the cross-scale structure of loofah micron-sized fibers and nanoscale cell wall pores. How to construct continuous, low-impedance ion transport channels within the micropores of loofah using green and gentle methods, while preserving the high strength and toughness of the loofah framework, thereby overcoming the voltage and lifespan bottlenecks of biomass power sources, is a technical challenge that needs to be solved.

[0004] To address the issues of weak interfacial bonding in existing biomass frameworks, blocked nanofluid channels, and low output voltage (typically <1.5V) in current wet gas power generation devices, it is necessary to construct a high-strength, high-voltage, multi-scale nanofluid channel-based natural porous biomass wet gas power generation device. This would allow for the continuous construction of multi-scale ion channels while preserving the strength of the natural framework, thereby improving power generation performance and mechanical strength. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a high-strength and tough ion-conducting composite material based on biomass interface modification, its preparation method, and its applications. This invention forcibly introduces hydroxyethyl cellulose into the micropores and deep layers of the cell walls of a natural porous biomass framework to construct continuous nanoscale ion transport channels. Through an externally driven cross-scale interface construction method, a natural porous biomass framework / hydroxyethyl cellulose / polyacrylamide composite gel material with high strength, toughness, and high ion conductivity is prepared. Flexible moisture-activated power devices assembled based on this material can achieve continuous construction of cross-scale ion channels while retaining the strength of the natural framework, thereby improving power generation performance and mechanical strength. This material can be applied to various scenarios such as hydroelectric power generation, moisture power generation, and metal-air batteries.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a high-strength and tough ion-conducting composite material based on biomass interface modification includes the following steps:

[0008] Step (1): Immerse the natural loofah sponge in the mixed alkaline solution and react. After the reaction is complete, wash and dry to obtain the purified loofah sponge fiber skeleton.

[0009] Step (2): Immerse the purified loofah fiber skeleton in an aqueous solution of hydroxyethyl cellulose and perform impregnation treatment using an external field-assisted impregnation process. After the treatment is completed, remove and dry to obtain a hydroxyethyl cellulose modified composite skeleton.

[0010] Step (3): Add electrolyte salt to water and stir to dissolve. Then add monomer, crosslinking agent, solvent regulator, and interface binder aqueous solution and stir to form precursor solution.

[0011] The hydroxyethyl cellulose-modified composite skeleton was immersed in a precursor solution and allowed to stand. An initiator and a catalyst were added, and the reaction was carried out. After the reaction was completed, a high-strength and tough ion-conducting composite material based on biomass interface modification was obtained.

[0012] Preferably, in step (1): the mixed alkaline solution is a mixed aqueous solution containing 10-30wt% sodium hydroxide and 5-20wt% hydrogen peroxide; the reaction conditions are: constant temperature reaction at 90-100℃ for 6-10h.

[0013] Furthermore, the reaction conditions in step (1) are: constant temperature reaction at 95°C for 8 hours.

[0014] Preferably, in step (1), the washing operation is: washing with ethanol and water alternately until the washing solution is neutral.

[0015] Preferably, in step (2), the concentration of hydroxyethyl cellulose in the aqueous solution of hydroxyethyl cellulose is 2-4.5 wt%.

[0016] Further, in step (2): the concentration of hydroxyethyl cellulose in the aqueous solution of hydroxyethyl cellulose is 4 wt%.

[0017] Preferably, in step (2), the impregnation process includes: using a high shear force dispersion device to perform high-intensity vibration treatment for 1-3 hours, and after the vibration treatment is completed, vacuuming is used to assist impregnation.

[0018] Furthermore, in step (2), the impregnation process includes: using a cell pulverizer with a power of 800W-1200W to perform high-intensity shaking treatment for 1-3 hours, and after the shaking treatment is completed, vacuum-assisted impregnation for 4 hours.

[0019] Preferably, in step (3), the electrolyte salt is lithium citrate and sodium chloride, the monomer is acrylamide, the crosslinking agent is N,N-methylenebisacrylamide, the solvent regulator is ethylene glycol, the interface adhesive aqueous solution is 2-6wt% tannic acid aqueous solution, the initiator is ammonium persulfate, and the catalyst is tetramethylethylenediamine;

[0020] The ratio of water, lithium citrate, sodium chloride, acrylamide, N,N-methylenebisacrylamide, ethylene glycol, 4wt% tannic acid aqueous solution, ammonium persulfate, and tetramethylethylenediamine is 5-10mL:10-100mg:10-100mg:1-4g:5-50mg:0.5-3mL:100-500μL:50-250mg:2-20μL.

[0021] Preferably, in step (3), the reaction conditions are: reacting at room temperature for 0.5-2 hours.

[0022] Preferably, the high-strength and tough ion-conducting composite material based on biomass interface modification is prepared by the preparation method of the high-strength and tough ion-conducting composite material based on biomass interface modification as described above.

[0023] Preferably, an application of the high-strength and tough ion-conducting composite material based on biomass interface modification as described above in a flexible power device is described. The preparation method of the flexible power device is as follows: the high-strength and tough ion-conducting composite material based on biomass interface modification is used as an electrolyte layer and is compositely assembled with a metal-air / moisture power generation electrode pair to obtain a flexible power device.

[0024] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0025] 1. This invention removes lignin and hemicellulose from natural loofah sponges, clearing macroscopic pores and exposing hydroxyl groups (-OH) on the cellulose surface, providing active sites for subsequent interfacial bonding. Driven by external forces such as ultrasonic dispersion or high-pressure homogenization, a high-viscosity hydroxyethyl cellulose solution is forced into the deep micropores and cell walls of the loofah fiber skeleton, forming a nanoscale coating within the micron-sized loofah fiber skeleton. This solves the problems of weak interfacial bonding and insufficient micropore filling caused by simple soaking methods. Furthermore, by generating conductive hydrogels in situ within the hydroxyethyl cellulose-modified composite skeleton, an integrated structure of rigid skeleton, interfacial layer, and flexible gel is formed. The resulting biomass-modified high-strength and tough ion-conducting composite material achieves a higher voltage output than traditional aluminum-air batteries because the hydroxyethyl cellulose coating constructs continuous nano-ion channels within the micron-sized skeleton. This, combined with the interfacial redox activity of tannic acid, reduces electrode contact resistance and electrochemical polarization. The flexible power device made from the above composite material can achieve a short-circuit current (Isc) of up to 120 μA and an output power density that is about 2000% higher than that of pure hydrogel.

[0026] 2. This invention solves the problems of weak bonding between the functional layer and the biomass skeleton and easy peeling under stress in traditional physical coating modification. Through the polyhydroxy structure of hydroxyethyl cellulose and the adhesive properties of tannic acid, a high-density hydrogen bond network is formed at the skeleton-gel interface, exhibiting excellent interfacial bonding and structural toughness. The device fully rebounds without interfacial debonding or structural collapse when subjected to 40% compressive deformation, proving that the modified skeleton is not only a support but also a stress dissipation network.

[0027] 3. The introduction of hydroxyethyl cellulose improves the hydrophobicity of the loofah sponge itself, making it more suitable for applications containing Li... + and Na + The electrolyte can deeply wet the framework. The hydroxyethyl cellulose molecular chain acts as an ion bridge, promoting rapid ion hopping transport, which is key to maintaining a continuous current at the microampere level, enabling the fabricated flexible power device to have low interfacial impedance and efficient ion transport.

[0028] 4. The synergistic effect of ethylene glycol and hydroxyethyl cellulose introduced into the system constructs an antifreeze and moisture-retaining network, which makes the device less prone to water loss and drying out during long-term operation in open environments. This solves the inherent defect of short lifespan of hydrogel devices and provides good environmental adaptability and long lifespan.

[0029] 5. This invention uses loofah sponge as raw material and adopts an aqueous phase system throughout the process, avoiding the use of toxic organic solvents (such as toluene, initiator residues, etc.) in traditional chemical grafting, which is in line with the principles of green chemistry. Attached Figure Description

[0030] Figure 1 These are photographs of the natural loofah sponge raw material and the purified loofah sponge fiber skeleton used in this invention.

[0031] Figure 2 This is a SEM image of the microstructure of the natural loofah fiber (untreated) in this invention;

[0032] Figure 3 This is a cross-sectional SEM image of the hydroxyethyl cellulose-modified composite skeleton prepared in Example 1 of this invention;

[0033] Figure 4 This is a physical image of a flexible power supply device assembled using the high-strength and tough ion-conducting composite material based on biomass interface modification prepared in Example 1 of this invention.

[0034] Figure 5 The test curves of the open-circuit voltage (Voc) and short-circuit current (Isc) of the flexible power device assembled based on the high-strength and tough ion-conducting composite material modified by biomass interface prepared in Example 1 of the present invention are shown.

[0035] Figure 6 The test curves show the changes in open-circuit voltage (Voc) and short-circuit current (Isc) over time for a flexible power supply device assembled using the loofah / polyacrylamide composite gel material prepared in Comparative Example 2 of this invention.

[0036] Figure 7 The flexible power supply device assembled using the high-strength and tough ion-conducting composite material based on biomass interface modification prepared in Example 1 of this invention is shown in the cyclic stress-strain curves under different compression ratios.

[0037] Figure 8 This is a schematic diagram of the structural deformation principle of a flexible power supply device assembled from a high-strength and tough ion-conducting composite material based on biomass interface modification prepared according to the present invention, under compression and tension.

[0038] In the picture, Figure 1The left image shows a photograph of natural loofah sponge raw material, and the right image shows a photograph of purified loofah sponge fiber skeleton.

[0039] Figure 3 In the image, the left image is a SEM image at 20 μm, and the right image is a SEM image at 3 μm. Detailed Implementation

[0040] The present invention will be further illustrated below through specific embodiments. The following embodiments are specific implementations of the present invention, but the implementation of the present invention is not limited to the following embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and are included within the protection scope of the present invention.

[0041] Example 1

[0042] This embodiment discloses a method for preparing a high-strength and tough ion-conducting composite material based on biomass interface modification, including the following steps:

[0043] Step (1): Prepare the loofah fiber skeleton;

[0044] After removing seeds and impurities, natural loofah sponge was cut into pieces and immersed in a mixed aqueous solution containing 20 wt% sodium hydroxide (NaOH) and 10 wt% hydrogen peroxide (H2O2). The solid-liquid ratio of the cut natural loofah sponge to the mixed aqueous solution containing 20 wt% sodium hydroxide and 10 wt% hydrogen peroxide was 1 g: 100 mL. The reaction was carried out in a constant temperature water bath at 95℃ for 8 h. After the reaction was completed, the loofah sponge was washed alternately with anhydrous ethanol and deionized water until the washing solution was neutral. The solution was then freeze-dried for later use to obtain the purified loofah sponge fiber skeleton, denoted as CLS skeleton.

[0045] Step (2): Prepare a hydroxyethyl cellulose-modified composite framework;

[0046] 4g of hydroxyethyl cellulose (HEC) powder was slowly added to 96mL of deionized water and stirred at high speed at 20℃ for 5h until completely dissolved to obtain a 4wt% hydroxyethyl cellulose aqueous solution.

[0047] The purified loofah fiber skeleton was completely immersed in a 4 wt% hydroxyethyl cellulose aqueous solution with a solid-liquid ratio of 1 g: 100 mL. The mixture was placed in a 1000 W cell disruptor and subjected to high-intensity shaking for 2 h. After shaking, the system was placed in a vacuum chamber and vacuumed for 4 h to remove air bubbles. After vacuum treatment, the sample was removed and dried at room temperature to obtain the hydroxyethyl cellulose modified composite skeleton, denoted as CLS-HEC skeleton.

[0048] Step (3): Prepare a loofah sponge / hydroxyethyl cellulose / polyacrylamide composite gel material;

[0049] Take 7 mL of deionized water, add 30 mg of lithium citrate (Li3Cit) and 30 mg of sodium chloride (NaCl) in sequence, stir to dissolve, then add 2 g of acrylamide (AM), 15 mg of N,N-methylenebisacrylamide (MBA), 1 mL of ethylene glycol (EG) and 200 μL of 4 wt% tannic acid (TA) aqueous solution, stir to form a homogeneous precursor solution;

[0050] The CLS-HEC framework was immersed in the precursor solution and allowed to stand for 2 hours for full penetration. Then, 140 mg of ammonium persulfate (APS) and 5 μL of tetramethylethylenediamine (TEMED) were added, and the mixture was quickly transferred to a mold (3×3×1 cm). The reaction was carried out at room temperature for 1 hour. After the reaction was completed, a loofah / hydroxyethyl cellulose / polyacrylamide composite gel material was obtained, which is a high-strength and tough ion-conducting composite material based on biomass interface modification, denoted as CLSH-HEC composite material.

[0051] Example 2

[0052] The difference from Example 1 is that in step (2), the 4 wt% hydroxyethyl cellulose aqueous solution is changed to a 2 wt% hydroxyethyl cellulose aqueous solution; other parameters and conditions are the same as in Example 1.

[0053] Example 3

[0054] The difference from Example 1 is that in step (2), the oscillation processing time is changed to 1 hour; other parameters and conditions are the same as in Example 1.

[0055] Comparative Example 1

[0056] This comparative example discloses a method for preparing a polyacrylamide gel material, including the following steps:

[0057] Take 7 mL of deionized water, add 30 mg of lithium citrate and 30 mg of sodium chloride in sequence, stir to dissolve, then add 2 g of acrylamide, 15 mg of N,N-methylenebisacrylamide, 1 mL of ethylene glycol and 200 μL of 4 wt% tannic acid aqueous solution, and stir to form a homogeneous precursor solution.

[0058] 140 mg of ammonium persulfate and 5 μL of tetramethylethylenediamine were added to the precursor solution and quickly transferred to a mold (3×3×1 cm). The mixture was reacted at room temperature for 1 h. After the reaction was completed, polyacrylamide gel material was obtained.

[0059] Comparative Example 2

[0060] This comparative example discloses a method for preparing a loofah / polyacrylamide composite gel material, including the following steps:

[0061] Step (1): Prepare the loofah fiber skeleton;

[0062] After removing seeds and impurities, natural loofah sponge was cut into pieces and immersed in a mixed aqueous solution containing 20 wt% sodium hydroxide and 10 wt% hydrogen peroxide. The solid-liquid ratio of the cut natural loofah sponge to the mixed aqueous solution containing 20 wt% sodium hydroxide and 10 wt% hydrogen peroxide was 1 g: 100 mL. The reaction was carried out in a constant temperature water bath at 95 ℃ for 8 h. After the reaction was completed, the loofah sponge was washed alternately with anhydrous ethanol and deionized water until the washing solution was neutral. The solution was then freeze-dried for later use to obtain the purified loofah sponge fiber skeleton, which was denoted as CLS skeleton.

[0063] Step (2): Prepare loofah sponge / polyacrylamide composite gel material;

[0064] Take 7 mL of deionized water, add 30 mg of lithium citrate and 30 mg of sodium chloride in sequence, stir to dissolve, then add 2 g of acrylamide, 15 mg of N,N-methylenebisacrylamide, 1 mL of ethylene glycol and 200 μL of 4 wt% tannic acid aqueous solution, and stir to form a homogeneous precursor solution.

[0065] The CLS skeleton was immersed in the precursor solution and allowed to stand for 2 hours to fully penetrate. Then, 140 mg of ammonium persulfate and 5 μL of tetramethylethylenediamine were added, and the mixture was quickly transferred to a mold (3×3×1 cm). The reaction was carried out at room temperature for 1 hour. After the reaction was completed, the loofah / polyacrylamide composite gel material was obtained.

[0066] Comparative Example 3

[0067] The difference from Example 1 is that in step (2), "high-intensity shaking treatment for 2 hours in a 1000W cell pulverizer" is replaced with "low-speed stirring at 150 rpm with a magnetic stirrer and soaking under normal pressure for 2 hours"; other parameters and conditions are the same as in Example 1.

[0068] Comparative Example 4

[0069] The difference from Example 1 is that in step (3), “200 μL of 4 wt% tannic acid aqueous solution” is replaced with “200 μL of deionized water”; other parameters and conditions are the same as in Example 1.

[0070] In the above embodiments and comparative examples: natural loofah sponge (LS) was commercially available; the cell shredder model was JY92-IIN.

[0071] Experimental data characterization and performance testing

[0072] like Figure 1As shown, the physical morphology of natural loofah fiber raw material is compared with that of loofah fiber skeleton after lignin and hemicellulose removal treatment. It can be seen that the loofah fiber skeleton after lignin and hemicellulose removal treatment maintains a complete macroscopic three-dimensional structure.

[0073] like Figure 2 and Figure 3 As shown, Figure 3 Microstructure of HEC-modified composite framework and Figure 2 Compared to the untreated loofah fiber skeleton, Figure 2 The untreated skeleton surface is smooth with large pore size and lacks nanofluid transport structure; Figure 3 By utilizing negative pressure, HEC further filled the pores and deep layers of the micron-sized loofah fiber skeleton, thus forming a continuous interfacial membrane. HEC constructed a continuous interfacial membrane and nanopores within the micron-sized skeleton, demonstrating the successful construction of cross-scale ion channels.

[0074] The composite gel materials prepared in Examples 1-3 and Comparative Examples 1-4 were used as electrolytes, aluminum mesh as anodes, and graphite paper or carbon cloth as cathodes, respectively, and were assembled into sandwich-structure flexible power supply devices. Graphite paper was preferred as the cathode material. A physical image of the flexible power supply device prepared in Example 1 is shown below. Figure 4 As shown;

[0075] The open-circuit voltage and polarization curves of the flexible power devices prepared in Examples 1-3 and Comparative Examples 1-4 were tested using an electrochemical workstation. The specific test results are shown in Table 1.

[0076] Table 1

[0077]

[0078] Depend on Figure 5 As shown in Table 1, the open-circuit voltage (Voc) of the flexible power device prepared in Example 1 was stable at 2.4V, and the short-circuit current (Isc) was 120μA; the open-circuit voltage (Voc) of the flexible power device prepared in Example 2 was 2.0V, and the short-circuit current (Isc) was 95μA, indicating that even with a low HEC concentration, an effective ion channel could still be formed, resulting in a higher voltage; the open-circuit voltage (Voc) of the flexible power device prepared in Example 3 was 2.1V, and the short-circuit current (Isc) was 100μA, indicating that reducing the high-shear treatment time would lead to insufficient micropore filling, resulting in a slight decrease in voltage and current, but it was still better than the traditional immersion process.

[0079] As shown in Table 1, the open-circuit voltage (Voc) of the flexible power device prepared by Comparative Example 1 is 1.2V and the short-circuit current (Isc) is 18μA, indicating that the device performance is low when the structural support of the biomass skeleton and the nanofluid channel effect are lacking.

[0080] Depend on Figure 6 As shown in Table 1, the flexible power device prepared by Comparative Example 2 has an open-circuit voltage (Voc) of 1.4V and a short-circuit current (Isc) of 30μA. Furthermore, the hydrogel layer easily peels off from the loofah skeleton during compression testing. Compared to the flexible power device prepared in Example 1, the lack of the HEC interface layer resulted in a voltage reduction of 1.0V, indicating that HEC combined with the high-shear filling process plays a crucial role in constructing low-impedance ion channels and enhancing interfacial charge transport.

[0081] As can be seen, compared to the device prepared using pure acrylamide hydrogel in Comparative Example 1 (Voc ≈ 1.2V) or the composite device prepared using loofah sponge without HEC interface modification in Comparative Example 2 (Voc ≈ 1.4V), the device prepared by Example 1 in this invention has an open-circuit voltage (Voc) as high as 2.4V, representing increases of 100% and 71%, respectively. This voltage increase is attributed to the high-shear-force-driven multi-scale filling of hydroxyethyl cellulose: the hydroxyethyl cellulose coating constructs continuous nano-ion channels within the micron-scale framework, which, combined with the interfacial redox activity of tannic acid, reduces electrode contact resistance and electrochemical polarization, thereby achieving a voltage output higher than that of traditional aluminum-air batteries, a short-circuit current (Isc) of 120 μA, and an output power density approximately 2000% higher than that of pure hydrogel.

[0082] As shown in Table 1, the open-circuit voltage (Voc) of the flexible power device prepared by Comparative Example 3 is 1.5 V, and the short-circuit current (Isc) is 35 μA. By comparing the electrical performance with that of the flexible power device prepared in Example 1, it can be seen that: the loofah has a complex micron-scale porous structure with significant capillary resistance and interfacial tension. Conventional "simple soaking" or "low-speed stirring" processes lack sufficient shear stress, making it difficult for the high molecular electrolyte (HEC) to enter the deep micropores, resulting in limited effective contact area. Therefore, "high shear force driving" is a necessary means to achieve "cross-scale interfacial wetting" between HEC and the multi-level pores of the loofah. The tight interfacial construction achieved by this process is the core of realizing a large voltage jump in the flexible power device.

[0083] As shown in Table 1, the open-circuit voltage (Voc) of the flexible power device prepared by Comparative Example 4 is 1.7 V, and the short-circuit current (Isc) is 60 μA. By comparing the electrical data with those of the flexible power device prepared in Example 1, it can be found that after removing TA, the device voltage drops from 2.4 V to 1.7 V. This is because the abundant phenolic hydroxyl structures in the TA molecule not only enhance the physical network (mechanical properties) through hydrogen bonds, but also help the reaction on the electrode surface to be smoother, thereby improving the charge transport efficiency. The combination of HEC and TA produces a dual synergistic effect of "structural support" and "charge transport enhancement".

[0084] like Figure 7 and Figure 8 As shown, in terms of mechanical properties, the flexible power device sample prepared by the present invention can instantly recover its original shape after being compressed to 40% deformation and the external force is removed, and no interface delamination phenomenon was found. It has excellent resilience and fatigue resistance. This is due to the synergistic effect of the loofah skeleton and the HEC interface layer. The device can maintain structural integrity under large mechanical deformation, which explains its "high strength and toughness" physical mechanism.

[0085] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for preparing a high-strength and tough ion-conducting composite material based on biomass interface modification, characterized in that, Includes the following steps: Step (1): Immerse the natural porous biomass framework in the mixed alkaline solution and react. After the reaction is complete, wash and dry to obtain the purified natural porous biomass framework. Step (2): The purified natural porous biomass skeleton is immersed in an aqueous solution of hydroxyethyl cellulose and impregnated using an external field-assisted impregnation process. After the process is completed, it is taken out and dried to obtain a hydroxyethyl cellulose modified composite skeleton. The impregnation process includes: using a cell disruptor with a power of 800W-1200W for high-intensity shaking treatment for 1-3 hours, followed by vacuum-assisted impregnation for 4 hours after the shaking treatment is completed. Step (3): Add electrolyte salt to water and stir to dissolve. Then add monomer, crosslinking agent, solvent regulator, and interface binder aqueous solution and stir to form precursor solution. The hydroxyethyl cellulose-modified composite skeleton was immersed in a precursor solution and allowed to stand. An initiator and a catalyst were added, and the reaction was carried out. After the reaction was completed, a high-strength and tough ion-conducting composite material based on biomass interface modification was obtained. In step (3), the electrolyte salts are lithium citrate and sodium chloride, the monomer is acrylamide, the crosslinking agent is N,N-methylenebisacrylamide, the solvent regulator is ethylene glycol, the interface adhesive aqueous solution is 4wt% tannic acid aqueous solution, the initiator is ammonium persulfate, and the catalyst is tetramethylethylenediamine; the ratio of water, lithium citrate, sodium chloride, acrylamide, N,N-methylenebisacrylamide, ethylene glycol, 4wt% tannic acid aqueous solution, ammonium persulfate, and tetramethylethylenediamine is 5-10mL:10-100mg:10-100mg:1-4g:5-50mg:0.5-3mL:100-500μL:50-250mg:2-20μL.

2. The method for preparing a high-strength and tough ion-conducting composite material based on biomass interface modification according to claim 1, characterized in that, In step (1): the natural porous biomass skeleton is natural loofah sponge; the mixed alkaline solution is a mixed aqueous solution containing 10-30wt% sodium hydroxide and 5-20wt% hydrogen peroxide; the reaction conditions are: constant temperature reaction at 90-100℃ for 6-10h.

3. The method for preparing a high-strength and tough ion-conducting composite material based on biomass interface modification according to claim 1, wherein in step (2): the concentration of hydroxyethyl cellulose in the aqueous solution of hydroxyethyl cellulose is 2-4.5 wt%.

4. The method for preparing a high-strength and tough ion-conducting composite material based on biomass interface modification according to claim 1, wherein in step (3), the reaction conditions are: reacting at room temperature for 0.5-2 hours.

5. A high-strength, high-toughness ion-conducting composite material based on biomass interface modification, prepared by the preparation method of the high-strength, high-toughness ion-conducting composite material based on biomass interface modification as described in any one of claims 1-4.

6. The application of a high-strength and tough ion-conducting composite material based on biomass interface modification as described in claim 5 in flexible power supply devices, characterized in that, The fabrication of flexible power supply devices includes the following steps: A flexible power supply device is obtained by using a high-strength and tough ion-conducting composite material modified based on biomass interface as the electrolyte layer and assembling it with a metal-air / moisture power generation electrode pair.

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