A SnS2-based composite electrode, its preparation method and application

Abstract

This invention belongs to the field of vanadium redox flow batteries, and relates to a SnS2-based composite electrode, its preparation method, and its application. The preparation method includes the following steps: S1: Adjusting the pH of a mixed aqueous solution containing a surfactant and a dispersant to 1.1-1.3 to obtain an acidic mixed system. S2: Adding a complexing agent and a tin source to obtain a tin source mixture. S3: Adding a sulfur source and reduced graphene oxide to obtain a reaction precursor solution. S4: Stirring and aging the reaction precursor solution under light-protected conditions. S5: Immersing a carbon cloth substrate in the aging precursor solution at 20-30°C under light-protected conditions for impregnation. S6: Drying after impregnation to obtain the SnS2-based composite electrode. The method of this invention has extremely mild process requirements, extremely low energy consumption, high repeatability, and simple equipment requirements. The prepared electrode has lower interfacial resistance and better cycle durability, meeting the requirements of high-performance flow batteries.

Description

Technical Field

[0001] This invention relates to the field of vanadium redox flow battery technology, specifically to a SnS2-based composite electrode, its preparation method, and its application. Background Technology

[0002] Vanadium redox flow batteries have attracted much attention in the field of large-scale energy storage due to their advantages such as power-capacity decoupling, long cycle life, and high safety. The performance of electrode materials directly determines the energy efficiency and operational stability of the battery. Tin disulfide, due to its unique layered structure and high theoretical activity, is a hot research topic when combined with reduced graphene oxide for use as an electrode in vanadium redox flow batteries.

[0003] In existing technologies, to obtain tin disulfide / reduced graphene oxide composite electrodes, common methods such as high-temperature hydrothermal methods, solvothermal methods, or physical mixing followed by calcination are typically used to first prepare tin disulfide / reduced graphene oxide composite powder, which is then coated onto a carbon cloth substrate using a binder. The preparation of the tin disulfide / reduced graphene oxide composite powder usually requires a closed, high-pressure environment with reaction temperatures exceeding 160°C, and sometimes even calcination at 250-500°C.

[0004] The existing preparation methods described above suffer from numerous process defects and performance shortcomings: Regarding the preparation process, existing technologies generally involve cumbersome steps and long preparation cycles. They require multiple independent steps, including powder synthesis, centrifugation, repeated washing, drying and grinding, and slurry coating, resulting in significant powder loss during transfer and washing, and necessitating long operating times and substantial equipment investment. In terms of loading methods, existing technologies require the introduction of insulating polymer binders and conductive additives into the tin disulfide / reduced graphene oxide composite powder for slurry coating, and the uniformity of the coating thickness is difficult to control precisely, leading to uneven distribution of the active material on the carbon cloth surface. Regarding interfacial bonding, the bonding force between the active layer, physically immobilized by the binder, and the carbon cloth substrate is limited, making it prone to detachment of the active material under actual operating conditions. Due to these limitations, electrodes prepared using existing technologies often exhibit high interfacial resistance and limited cycle durability, failing to meet the practical application requirements of high-efficiency and long-life electrode materials in high-performance flow batteries.

[0005] Therefore, there is a need to provide an electrode with higher energy efficiency and better cycle stability. Summary of the Invention

[0006] (a) Technical problems to be solved To address the problems of cumbersome preparation process, high energy consumption, large powder loss, uneven loading of active material and poor bonding with the substrate, and limited overall electrode performance in existing technologies, this invention provides a SnS2-based composite electrode, its preparation method, and its application.

[0007] (II) Technical Solution To achieve the above objectives, the main technical solutions adopted by the present invention include: In a first aspect, the present invention provides a method for preparing a SnS2-based composite electrode, comprising the following steps: S1: Provide a mixed aqueous solution containing surfactants and dispersants, and adjust the pH of the mixed aqueous solution to 1.1-1.3 to obtain an acidic mixed system; S2: Add a complexing agent and a tin source to the acidic mixture to obtain a tin source mixture; S3: Add sulfur source and reduced graphene oxide to tin source mixture to obtain reaction precursor solution; S4: The reaction precursor solution is stirred and matured under light-protected conditions to obtain a matured precursor solution; S5: Immerse the carbon cloth substrate in the aging precursor solution at 20-30℃ and in the dark for impregnation treatment, so that the tin source and sulfur source react in situ on the surface of the carbon cloth substrate to generate SnS2, which is then loaded onto the carbon cloth substrate together with the reduced graphene oxide. S6: After impregnation, a drying process is performed to obtain the SnS2-based composite electrode.

[0008] In the SnS2-based composite electrode preparation method described above, optionally, in step S1, the surfactant is polyethylene glycol monolaurate or fatty alcohol polyoxyethylene ether, and the dispersant is hexadecyltrimethylammonium bromide, sodium dodecyl sulfate or polyvinylpyrrolidone, with a mass ratio of surfactant to dispersant of 1:1-3:1, and the pH of the mixed aqueous solution is adjusted to 1.1-1.3 by concentrated hydrochloric acid.

[0009] In the SnS2-based composite electrode preparation method described above, optionally, in step S2, the complexing agent is citric acid, the tin source is stannous chloride, and the amount of citric acid added in the tin source mixture is 1.5-2 g / L; the molar ratio of citric acid to stannous chloride is (0.5-0.8):1.

[0010] In the SnS2-based composite electrode preparation method described above, optionally, in step S3, the sulfur source is thiourea; the molar ratio of thiourea to the tin source in step S2 is (2.5-4):1.

[0011] In the SnS2-based composite electrode preparation method described above, optionally, in step S3, reduced graphene oxide is added in the form of a dispersion, the concentration of the reduced graphene oxide dispersion is 0.5-1.5 g / L, and the volume ratio of the added reduced graphene oxide dispersion to the volume of the mixed aqueous solution is 1:(600-1000).

[0012] In the SnS2-based composite electrode preparation method described above, optionally, in step S4, the stirring and ripening treatment time is 15-30 min.

[0013] In the SnS2-based composite electrode preparation method described above, optionally, in step S5, the impregnation treatment time is 2.5-3.5 h.

[0014] Optionally, in step S6, after impregnation, the SnS2-based composite electrode is prepared by vacuum drying at 40-60℃ and a vacuum degree of -0.08MPa to -0.09MPa for 10-14 hours in the dark to obtain the SnS2-based composite electrode.

[0015] Secondly, the present invention provides a SnS2-based composite electrode, which is prepared by the above-described preparation method; The SnS2-based composite electrode comprises, by mass percentage, 94.5-96.0% carbon cloth substrate, 3.0-4.0% SnS2, 0.3-0.5% reduced graphene oxide, with the remainder being residual components; the residual components include surfactants, dispersants, and complexing agents.

[0016] Thirdly, the present invention also provides an electrode prepared by the above-mentioned SnS2-based composite electrode preparation method, or the application of the above-mentioned SnS2-based composite electrode in vanadium redox flow batteries, zinc-bromine flow batteries, iron-chromium flow batteries, lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, asymmetric supercapacitors, lithium-sulfur batteries, water electrolysis hydrogen production devices, carbon dioxide reduction catalysts, or electrochemical sensors.

[0017] (III) Beneficial Effects The preparation method of this invention constructs a strongly acidic mixed system with a pH of 1.1-1.3 by compounding a surfactant and a dispersant, and combining the sequential addition of a complexing agent, tin source, sulfur source, and reduced graphene oxide with a light-shielded curing treatment. This allows the tin source and sulfur source to react in situ on the carbon cloth substrate surface at room temperature (20-30°C) to directly generate SnS2, which is then co-loaded onto the carbon cloth substrate with the reduced graphene oxide. Compared with existing preparation methods that require high-temperature hydrothermal treatment above 160°C or calcination at 250-500°C and the addition of a binder for coating, the preparation method of this invention has significant technical advantages. In terms of process, the preparation method of the present invention integrates the synthesis and loading of the active substance SnS2 into a one-step impregnation operation, eliminating multiple steps such as centrifugation, repeated washing, drying and grinding, and slurry coating after powder synthesis in the prior art. This greatly simplifies the preparation process, shortens the operation cycle, and avoids material loss during powder transfer and washing.

[0018] Regarding the loading method, the preparation method of the present invention does not require the introduction of insulating binders and conductive additives. Instead, it relies on the in-situ reaction of tin source and sulfur source on the surface of carbon cloth substrate to directly form active components, which fundamentally eliminates the problem of uneven distribution of active materials caused by physical fixation of binders. At the same time, the SnS2 generated in situ forms a tight interfacial bond with the carbon cloth substrate, which significantly enhances the adhesion stability of active materials under working conditions.

[0019] Based on the above improvements, the SnS2-based composite electrode prepared by the method of the present invention can exhibit lower interfacial resistance and better cycle durability, thereby effectively solving the problems of cumber disulfide-based composite electrode preparation process, high energy consumption, large powder loss, uneven loading of active material and poor bonding with the substrate, and limited overall electrode performance in the prior art, thus meeting the application requirements of high efficiency and long life of electrode materials for high-performance flow batteries. Attached Figure Description

[0020] Figure 1 Efficiency-cycle results of the SnS2-based composite electrode prepared in Example 1; Figure 2 The efficiency-cycle results of the SnS2-based composite electrode prepared in Example 2 are shown in the figure. Figure 3 Efficiency-cycle results of the SnS2-based composite electrode prepared for Comparative Example 1; Figure 4 Efficiency-cycle results of the SnS2-based composite electrode prepared for Comparative Example 2; Figure 5 Efficiency-cycle results of the SnS2-based composite electrode prepared for Comparative Example 3; Figure 6 The efficiency-cycle results of the SnS2-based composite electrode prepared for Comparative Example 4 are shown in the figure. Figure 7 The graph shows a comparison of the voltage efficiency and cycle stability of the SnS2-based composite electrodes prepared in each embodiment and comparative example. Detailed Implementation

[0021] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] This invention provides a method for preparing a SnS2-based composite electrode, comprising the following steps: S1: Provide a mixed aqueous solution containing surfactant and dispersant, and adjust the pH of the mixed aqueous solution to 1.1-1.3 to obtain an acidic mixed system.

[0023] S2: Add a complexing agent and a tin source to the acidic mixture to obtain a tin source mixture.

[0024] S3: Add sulfur source and reduced graphene oxide to the tin source mixture to obtain the reaction precursor solution.

[0025] S4: The precursor solution is stirred and matured under light-protected conditions to obtain a matured precursor solution.

[0026] S5: Immerse the carbon cloth substrate in the aging precursor solution at 20-30℃ and in the dark for impregnation treatment, so that the tin source and sulfur source react in situ on the surface of the carbon cloth substrate to generate SnS2, which is then loaded onto the carbon cloth substrate together with reduced graphene oxide.

[0027] S6: After impregnation, a drying process is performed to obtain the SnS2-based composite electrode.

[0028] This invention constructs a strongly acidic composite system, which enables the in-situ generation of SnS2 on the surface of a carbon cloth substrate and its co-loading with reduced graphene oxide at room temperature, thereby producing a composite electrode that requires no binder and has a strong active layer bond in one step.

[0029] In step S1, the surfactant is polyethylene glycol monolaurate or fatty alcohol polyoxyethylene ether, and the dispersant is hexadecyltrimethylammonium bromide, sodium dodecyl sulfate, or polyvinylpyrrolidone. Polyethylene glycol monolaurate and fatty alcohol polyoxyethylene ether are nonionic surfactants whose molecular structures contain both hydrophilic polyoxyethylene segments and hydrophobic alkyl segments, enabling them to form micelle templates in solution and play a role in spatial confinement and morphology regulation for the subsequent nucleation and growth of SnS2. The dispersant and surfactant have a synergistic effect, enhancing the wetting and penetration ability of the solution on the carbon cloth while preventing the aggregation of nanoparticles. The combined use of surfactant and dispersant is more effective than using a single reagent in controlling the particle size distribution and deposition uniformity of SnS2. In step S1, the mass ratio of surfactant to dispersant is preferably 1:1-3:1, more preferably 2:1, and the pH of the mixed aqueous solution can be adjusted to 1.1-1.3 using concentrated hydrochloric acid. This mass ratio range ensures that the surfactant and dispersant form a stable compound micelle structure, resulting in the best effect on subsequent control of SnS2 particle size and distribution.

[0030] Specifically, a surfactant and dispersant can be added to deionized water and stirred at room temperature for 15-20 minutes at a stirring rate of 300-400 rpm until completely dissolved and the solution is colorless and transparent. The concentration of the dispersant is approximately 0.2-0.3 g / L. Then, 37% concentrated hydrochloric acid is added dropwise while stirring continuously until the pH of the solution stabilizes within the range of 1.1-1.3. In practice, if the pH is too low, a small amount of deionized water can be added dropwise to fine-tune it.

[0031] Adjusting the pH to a strongly acidic range of 1.1-1.3 is one of the key technical means for achieving room temperature in-situ synthesis in this invention. Under strongly acidic conditions of pH 1.1-1.3, the hydrolysis desulfurization rate of thiourea is effectively suppressed, avoiding explosive homogeneous nucleation of the tin and sulfur sources in the bulk solution. This lays the foundation for slow and controllable heterogeneous nucleation on the carbon cloth surface during the subsequent impregnation stage. Simultaneously, the strongly acidic conditions suppress the hydrolysis of stannous chloride, keeping tin ions in a stable dissolved state, facilitating the subsequent formation of a soluble complex with citric acid.

[0032] In step S2 above, the citric acid molecule contains multiple carboxyl and hydroxyl coordination sites, which can interact with Sn. 2+ A stable water-soluble complex is formed. The purpose of complexation is to further inhibit Sn in strongly acidic systems. 2+ The release and hydrolysis of tin allow the tin source to exist in the solution in a uniformly dispersed state at the molecular level. Preferably, the amount of citric acid added to the tin source mixture is controlled at 1.5-2 g / L, and the molar ratio of citric acid to stannous chloride is controlled within the range of (0.5-0.8):1. If the amount of citric acid is too low, the hydrolysis inhibition effect will be insufficient, and the solution will easily become turbid.

[0033] Specifically, in step S2, while maintaining room temperature and a stirring rate of 300-400 r / min, citric acid is added to the acidic mixture from step S1, and the mixture is stirred for 5-8 minutes until the citric acid is completely dissolved and the solution remains colorless and transparent. Then, the tin source is immediately added, and stirring continues for 3-5 minutes. Because Sn... 2+ Even under strongly acidic conditions, trace amounts of hydrolysis may still occur to form Sn(OH)Cl. In this case, the solution state needs to be observed: if the solution is slightly turbid, it indicates that partial hydrolysis has occurred, and concentrated hydrochloric acid should be added dropwise while stirring for 2 minutes until the solution becomes clear again. If the solution is clear, proceed directly to the next step.

[0034] Preferably, in step S3, the sulfur source is thiourea, and the molar ratio of thiourea to the tin source in step S2 is (2.5-4):1. The reduced graphene oxide can be added in the form of a dispersion, the concentration of the reduced graphene oxide dispersion is 0.5-1.5 g / L, and the volume ratio of the added reduced graphene oxide dispersion to the volume of the mixed aqueous solution is 1:(600-1000).

[0035] In step S3, thiourea, acting as a sulfur source, is inhibited in decomposition under strongly acidic conditions. Therefore, only Sn decomposition occurs during the solution preparation and aging stages. 2+ The thiourea is pre-complexed with thiourea without generating a large amount of SnS2 precipitate. The molar ratio of thiourea to the tin source in step S2 is controlled within the range of (2.5-4):1, which can provide sufficient sulfur source to ensure the complete formation of SnS2, while avoiding excessive sulfur source that would lead to impurity residue.

[0036] After the reduced graphene oxide (rGO) sheets are uniformly dispersed in solution, their abundant oxygen-containing functional groups and defect sites on the surface can interact with Sn. 2+ The complex undergoes weak interactions, allowing the rGO sheets and precursor components to interweave uniformly at the molecular scale. The purpose of this step is to pre-construct a conductive network framework to ensure the subsequent application of Sn... 2+ During in-situ generation, rGO can be synchronously embedded or interspersed within Sn. 2+ Between the particles, a continuous electron transport channel is formed, rather than simply adhering to the electrode surface.

[0037] Specifically, in step S3, while maintaining room temperature and a stirring rate of 300-400 r / min, thiourea is gradually added to the clear solution from step S2. To promote dissolution and avoid excessively high local concentrations, the thiourea should be added in 3-4 portions, stirring continuously after each addition until completely dissolved. After all the thiourea has been added and dissolved, the solution will be clear and pale yellow; at this point, Sn... 2+ It initially complexes with thiourea to form a precursor. Subsequently, the rGO dispersion is slowly added dropwise, and stirring is continued for 5 minutes after the addition is complete to ensure that the rGO is uniformly dispersed in the solution without agglomeration.

[0038] Preferably, in step S4, the stirring time for the maturation treatment is 15-30 minutes. Under continuous stirring, Sn 2 + -Citrate complex, Sn 2+ - The thiourea pre-complex and rGO sheets are in full contact and uniformly dispersed at the molecular level. The light-protected operation is to prevent the thiourea from photodecomposing under light conditions and prematurely releasing S. 2- This avoids the formation of SnS2 precipitate in the bulk solution. The precursor solution after aging remains clear and pale yellow, with no obvious precipitate, indicating that the system is in a stable state suitable for subsequent impregnation reactions.

[0039] Specifically, in step S4, the room temperature and stirring rate of 300-400 r / min are maintained, and the precursor solution obtained in step S3 is stirred for about 20 minutes. During the stirring process, the container can be wrapped with a black light-blocking cloth or placed in a light-proof box. If the curing step is omitted and impregnation is carried out directly, the uneven concentration in the solution will cause SnS2 to undergo non-uniform nucleation on the carbon cloth surface in the early stage of impregnation. The resulting active layer particles will have severe agglomeration and poor bonding force, and the electrode performance will be significantly degraded.

[0040] In step S5, the impregnation temperature range is 20-30℃, i.e., room temperature. This temperature condition is one of the core features that distinguishes this invention from the existing high-temperature hydrothermal or high-temperature calcination methods. Under room temperature conditions, the decomposition rate of thiourea in the precursor solution is extremely slow, and the SnS2 formation reaction occurs preferentially only at the active sites on the carbon fiber surface. The carbon fiber surface has a certain number of oxygen-containing functional groups, defect sites, and edge unsaturated carbon atoms, which can induce heterogeneous nucleation of the precursor complex on its surface. As the impregnation time increases, SnS2 nanoparticles are gradually generated and grown on the carbon fiber surface, and synchronously composite and deposited with the uniformly dispersed rGO sheets in the solution. Because the reaction proceeds slowly at room temperature, SnS2 grows uniformly at a nanoscale size of 5-20 nm, avoiding the excessive growth and agglomeration of particles commonly seen under high-temperature conditions.

[0041] The preferred impregnation time is 2.5-3.5 hours. Within this time range, the formation and loading of SnS2 can reach a relatively ideal level. If the impregnation time is too short, the loading will be insufficient and the number of active sites will be too small. If the impregnation time is too long, the active layer may be too thick, increasing mass transfer resistance and reducing production efficiency.

[0042] The carbon cloth substrate needs to be pretreated before impregnation. Specifically, it is first ultrasonically cleaned with anhydrous ethanol for 10 minutes to remove surface oil, then ultrasonically cleaned with deionized water for 10 minutes to remove residual ethanol, and finally placed in a vacuum drying oven and dried at 50°C for 30 minutes for later use. The pretreated carbon cloth surface is clean and has improved hydrophilicity, which is beneficial for the wetting of precursor solutions and the full exposure of active sites.

[0043] During the impregnation process, the pretreated carbon cloth is completely immersed in the aging precursor solution obtained in step S4, ensuring that both sides and pores of the carbon cloth are wetted by the solution without any residual air bubbles. The entire impregnation process should be conducted in the dark; the container can be placed in a light-proof box. Impregnate at room temperature for approximately 3 hours. During the impregnation process, gently shake the container once every 20-30 minutes to ensure uniform loading across the carbon cloth surface and avoid localized overloading or underloading due to concentration gradients.

[0044] The mechanism of the in-situ reaction in step S5 is as follows: under the induction of active sites on the surface of carbon cloth fibers, Sn... 2+- Citric acid complexes react with thiourea to slowly release S 2- A reaction occurs, resulting in heterogeneous nucleation of SnS2 nanoparticles on the carbon fiber surface. Simultaneously, uniformly dispersed rGO sheets in the solution are encapsulated or interpenetrated by the growing SnS2 particles, ultimately forming an active layer structure where SnS2 and rGO are tightly composited and directly chemically bonded to the carbon cloth substrate. This in-situ growth mechanism ensures a strong interfacial bond between SnS2 and carbon cloth, fundamentally eliminating the interfacial resistance and active material detachment problems caused by binders in traditional coating methods.

[0045] In step S6, preferably, the drying process is carried out under vacuum conditions, with a temperature of 40-60℃, a vacuum degree of -0.08MPa to -0.09MPa, and a drying time of 10-14 hours. Vacuum drying can quickly remove the adsorbed moisture from the carbon cloth and the active composite layer, avoiding the agglomeration or oxidation of active substances caused by residual moisture. The drying process should also be carried out under light-protected conditions to prevent photochemical oxidation of SnS2 due to light exposure.

[0046] In the specific operation, the impregnated carbon cloth is removed from the precursor solution, and the edges are gently grasped with tweezers to drain excess solution from the surface. Rinsing is unnecessary to avoid detachment of the active material. It is then immediately placed in a vacuum drying oven and dried in the dark at the set temperature and vacuum level. After drying, the bonding between the active composite layer and the carbon cloth substrate becomes tighter, resulting in a finished electrode that can be directly used in vanadium redox flow batteries.

[0047] Throughout the entire preparation process of this invention, the order in which reagents are added cannot be reversed. In particular, the order of addition of the tin source and the sulfur source must be strictly followed after the citric acid complexation of Sn. 2+ Then add thiourea, otherwise it will cause Sn 2+ Rapid hydrolysis and uneven reaction with the sulfur source produce a large number of aggregates. The light-protected conditions are mainly for the curing stage in step S4, the impregnation stage in step S5, and the drying stage in step S6. The dissolution and mixing operations in steps S1-S3 can be carried out under natural light, but direct exposure to strong light should be avoided.

[0048] The SnS2-based composite electrode prepared by the above method comprises, by mass percentage, 94.5-96.0% carbon cloth substrate, 3.0-4.0% SnS2, and 0.3-0.5% reduced graphene oxide, with the remainder being residual components. These residual components mainly originate from the surfactants, dispersants, and complexing agents used in the preparation process; their content is extremely low and does not affect the electrochemical performance of the electrode.

[0049] The carbon cloth substrate serves as a supporting framework and electron transport channel. Even after loading the active material, its porous structure is preserved, ensuring electrolyte permeability. SnS2, exhibiting a hexagonal layered structure, is the core energy storage active material of the electrode. It is uniformly dispersed at the molecular level within the active composite layer, with a particle size of 5-20 nm. It is loaded onto the carbon cloth surface through in-situ reaction, forming a good interfacial bond with the carbon cloth. rGO's main function is to enhance the conductivity of the active composite layer and inhibit the aggregation of SnS2 nanoparticles. Its layered structure is uniformly interspersed between the SnS2 particles, used to construct a continuous conductive network.

[0050] The SnS2-based composite electrode provided by this invention can be used not only in vanadium redox flow batteries, but also as an electrode material for flow battery systems such as zinc-bromine flow batteries and iron-chromium flow batteries. It can also be used as a negative electrode material for lithium-ion batteries, sodium-ion batteries, and potassium-ion batteries, or as a negative electrode material for asymmetric supercapacitors, an intermediate layer or sulfur host for lithium-sulfur batteries, a catalyst for hydrogen evolution reaction, a catalyst for carbon dioxide reduction, and a working electrode for electrochemical sensors, etc., and has broad electrochemical application prospects.

[0051] To further clarify the present invention and its technological advancements, the following description is provided in conjunction with specific embodiments and technical effects.

[0052] Example 1: This embodiment provides a method for preparing a SnS2-based composite electrode, including the following steps: S1: Polyethylene glycol monolaurate and CTAB were added to deionized water at 25°C and stirred at room temperature for 18 minutes at a stirring rate of 350 rpm using a magnetic stirrer until completely dissolved, yielding a colorless and transparent mixed aqueous solution. The concentration of CTAB was 0.25 g / L, and the mass ratio of polyethylene glycol monolaurate to CTAB was 2:1. Subsequently, concentrated hydrochloric acid with a mass fraction of 37% was added dropwise while stirring until the pH of the solution stabilized at 1.2, resulting in an acidic mixed system.

[0053] S2: In step S2, while maintaining a temperature of 25°C and a stirring speed of 350 rpm, citric acid is added to the acidic mixture and stirred for 6 minutes until the citric acid is completely dissolved and the solution remains colorless and transparent. Stannous chloride is then immediately added, and stirring continues for 4 minutes. The solution becomes slightly turbid; concentrated hydrochloric acid is added dropwise, and stirring continues for 2 minutes until the solution becomes clear again. In this step, the amount of citric acid added is controlled at 1.85 g / L, and the molar ratio of citric acid to stannous chloride is 0.58:1.

[0054] S3: Maintaining a constant temperature of 25℃ and a stirring rate of 350 r / min, gradually add thiourea to the clear solution from step S2. Specifically, add it in three portions, stirring continuously after each addition until completely dissolved. After all the thiourea has been added and dissolved, slowly add the rGO dispersion dropwise, stirring for another 5 minutes after the addition is complete to obtain the reaction precursor solution. In this step, the molar ratio of thiourea to stannous chloride is 3:1, the concentration of the reduced graphene oxide dispersion is 1 g / L, and the volume ratio of the added reduced graphene oxide dispersion to the mixed aqueous solution is 1:800.

[0055] S4: Continue to maintain the stirring rate of 350r / min at 25℃ and 350r / min, and continue to stir the precursor solution obtained in step S3 for 20min. During the stirring process, wrap the container with a black light-blocking cloth.

[0056] S5: First, ultrasonically clean a 2cm×3cm sheet of carbon cloth substrate with anhydrous ethanol for 10 minutes, then ultrasonically clean it with deionized water for 10 minutes. Finally, place it in a vacuum drying oven and dry at 50℃ for 30 minutes for later use. Completely immerse the pretreated carbon cloth in the cured precursor solution, ensuring that both sides and pores of the carbon cloth are wetted by the solution without any air bubbles remaining. The immersion process should be conducted in the dark, maintaining immersion at 25℃ for 3 hours, gently shaking the cloth once every 30 minutes during the immersion process.

[0057] S6: Remove the impregnated carbon cloth from the precursor solution, gently pinch the edges with tweezers, drain the excess solution from the surface, and then immediately place it in a vacuum drying oven. Dry it in the dark at 50℃ and a vacuum of -0.085MPa for 12 hours to obtain the SnS2-based composite electrode.

[0058] Example 2: This embodiment provides a method for preparing a SnS2-based composite electrode, including the following steps: S1: At 20℃, fatty alcohol polyoxyethylene ether and sodium dodecyl sulfate were added to deionized water. The mixture was stirred at 300 rpm for 15 minutes at room temperature using a magnetic stirrer until completely dissolved, resulting in a colorless and transparent mixed aqueous solution. The concentration of sodium dodecyl sulfate was 0.2 g / L, and the mass ratio of fatty alcohol polyoxyethylene ether to sodium dodecyl sulfate was 1:1. Subsequently, concentrated hydrochloric acid (37% by mass) was added dropwise while stirring until the pH of the solution stabilized at 1.1, resulting in an acidic mixed system.

[0059] S2: In step S2, while maintaining a temperature of 20°C and a stirring speed of 300 rpm, add citric acid to the acidic mixture and stir for 5 minutes until the citric acid is completely dissolved and the solution remains colorless and transparent. Immediately afterwards, add stannous chloride and continue stirring for 3 minutes. The solution will become slightly turbid; add concentrated hydrochloric acid dropwise and continue stirring for 2 minutes until the solution becomes clear again. In this step, the amount of citric acid added is controlled at 1.5 g / L, and the molar ratio of citric acid to stannous chloride is 0.5:1.

[0060] S3: Maintaining a constant temperature of 20℃ and a stirring rate of 300 r / min, gradually add thiourea to the clear solution from step S2. Specifically, add it in four portions, stirring continuously after each addition until completely dissolved. After all the thiourea has been added and dissolved, slowly add the rGO dispersion dropwise, stirring for another 5 minutes after each addition to obtain the reaction precursor solution. In this step, the molar ratio of thiourea to stannous chloride is 2.5:1, the concentration of the reduced graphene oxide dispersion is 0.5 g / L, and the volume ratio of the added reduced graphene oxide dispersion to the mixed aqueous solution is 1:600.

[0061] S4: Continue to maintain the stirring rate of 20℃ and 300r / min, and continue to stir the precursor solution obtained in step S3 for 15min. During the stirring process, wrap the container with a black light-blocking cloth.

[0062] S5: First, ultrasonically clean the 2cm×3cm sheet carbon cloth substrate with anhydrous ethanol for 10 minutes, then ultrasonically clean it with deionized water for 10 minutes. Finally, place it in a vacuum drying oven and dry at 50℃ for 30 minutes for later use. Completely immerse the pretreated carbon cloth in the cured precursor solution, ensuring that both sides and pores of the carbon cloth are wetted by the solution without any air bubbles remaining. The immersion process should be conducted in the dark, maintaining immersion at 20℃ for 2.5 hours, gently shaking the cloth once every 30 minutes during the immersion process.

[0063] S6: Remove the impregnated carbon cloth from the precursor solution, gently pinch the edges with tweezers, drain the excess solution from the surface, and then immediately place it in a vacuum drying oven. Dry it in the dark at 40℃ and -0.08MPa for 10 hours to obtain the SnS2-based composite electrode.

[0064] Example 3: This embodiment provides a method for preparing a SnS2-based composite electrode, including the following steps: S1: Polyethylene glycol monolaurate and polyvinylpyrrolidone were added to deionized water at 30℃. The mixture was stirred at 400 rpm for 20 minutes at room temperature using a magnetic stirrer until completely dissolved, yielding a colorless and transparent aqueous solution. The concentration of polyvinylpyrrolidone was 0.3 g / L, and the mass ratio of polyethylene glycol monolaurate to polyvinylpyrrolidone was 3:1. Subsequently, concentrated hydrochloric acid (37% by mass) was added dropwise while stirring until the pH of the solution stabilized at 1.3, resulting in an acidic mixed system.

[0065] S2: In step S2, while maintaining a temperature of 30°C and a stirring speed of 400 rpm, citric acid is added to the acidic mixture and stirred for 8 minutes until the citric acid is completely dissolved and the solution remains colorless and transparent. Stannous chloride is then immediately added, and stirring continues for 5 minutes. The solution is observed to be clear. In this step, the amount of citric acid added is controlled at 2 g / L, and the molar ratio of citric acid to stannous chloride is 0.8:1.

[0066] S3: Maintaining a constant temperature of 30℃ and a stirring speed of 400 r / min, gradually add thiourea to the clear solution from step S2. Specifically, add in four portions, stirring continuously after each addition until completely dissolved. After all the thiourea has been added and dissolved, slowly add the rGO dispersion dropwise, stirring for another 5 minutes after each addition to obtain the reaction precursor solution. In this step, the molar ratio of thiourea to stannous chloride is 4:1, the concentration of the reduced graphene oxide dispersion is 1.5 g / L, and the volume ratio of the added reduced graphene oxide dispersion to the mixed aqueous solution is 1:1000.

[0067] S4: Continue to maintain the stirring rate of 30℃ and 400r / min, and continue to stir the precursor solution obtained in step S3 for 30min. During the stirring process, wrap the container with a black light-blocking cloth.

[0068] S5: First, ultrasonically clean the 2cm×3cm sheet carbon cloth substrate with anhydrous ethanol for 10 minutes, then ultrasonically clean it with deionized water for 10 minutes. Finally, place it in a vacuum drying oven and dry at 50℃ for 30 minutes for later use. Completely immerse the pretreated carbon cloth in the cured precursor solution, ensuring that both sides and pores of the carbon cloth are wetted by the solution without any air bubbles remaining. The immersion process should be conducted in the dark, maintaining immersion at 30℃ for 3.5 hours, gently shaking the cloth once every 30 minutes during the immersion process.

[0069] S6: Remove the impregnated carbon cloth from the precursor solution, gently pinch the edges with tweezers, drain the excess solution from the surface, and then immediately place it in a vacuum drying oven. Dry it in the dark at 60℃ and -0.09MPa for 14 hours to obtain the SnS2-based composite electrode.

[0070] Example 4: This embodiment provides a method for preparing a SnS2-based composite electrode, including the following steps: S1: Polyethylene glycol monolaurate and CTAB were added to deionized water at 27°C and stirred at room temperature for 16 minutes at 360 rpm using a magnetic stirrer until completely dissolved, yielding a colorless and transparent mixed aqueous solution. The concentration of CTAB was 0.28 g / L, and the mass ratio of polyethylene glycol monolaurate to CTAB was 2.5:1. Subsequently, concentrated hydrochloric acid (37% by mass) was added dropwise while stirring until the pH of the solution stabilized at 1.25, resulting in an acidic mixed system.

[0071] S2: In step S2, maintain a temperature of 27°C and a stirring speed of 360 rpm. Add citric acid to the acidic mixture and stir for 7 minutes until the citric acid is completely dissolved and the solution remains colorless and transparent. Immediately add stannous chloride and continue stirring for 5 minutes. Observe the solution state: if the solution is slightly turbid, add concentrated hydrochloric acid dropwise and continue stirring for 2 minutes until the solution becomes clear again. If the solution is clear, proceed directly to the next step. In this step, the amount of citric acid added is controlled at 1.75 g / L, and the molar ratio of citric acid to stannous chloride is 0.7:1.

[0072] S3: Maintaining a constant temperature of 27℃ and a stirring rate of 360 r / min, gradually add thiourea to the clear solution from step S2. Specifically, add it in three portions, stirring continuously after each addition until completely dissolved. After all the thiourea has been added and dissolved, slowly add the rGO dispersion dropwise, stirring for another 5 minutes after the addition is complete to obtain the reaction precursor solution. In this step, the molar ratio of thiourea to stannous chloride is 3.3:1, the concentration of the reduced graphene oxide dispersion is 1.1 g / L, and the volume ratio of the added reduced graphene oxide dispersion to the mixed aqueous solution is 1:700.

[0073] S4: Continue to maintain the stirring rate of 360r / min at 27℃ and 360r / min, and continue to stir the precursor solution obtained in step S3 for 17min. During the stirring process, wrap the container with a black light-blocking cloth.

[0074] S5: First, ultrasonically clean the 2cm×3cm sheet carbon cloth substrate with anhydrous ethanol for 10 minutes, then ultrasonically clean it with deionized water for 10 minutes. Finally, place it in a vacuum drying oven and dry at 50℃ for 30 minutes for later use. Completely immerse the pretreated carbon cloth in the cured precursor solution, ensuring that both sides and pores of the carbon cloth are wetted by the solution without any air bubbles remaining. The immersion process should be conducted in the dark at 27℃ for 3.2 hours, gently shaking the cloth once every 30 minutes during the immersion process.

[0075] S6: Remove the impregnated carbon cloth from the precursor solution, gently pinch the edges with tweezers, drain the excess solution from the surface, and then immediately place it in a vacuum drying oven. Dry it in the dark at 48℃ and -0.08MPa for 13 hours to obtain the SnS2-based composite electrode.

[0076] Comparative Example 1: This comparative example provides a method for preparing a SnS2-based composite electrode, comprising the following steps: S1: Stannous chloride and thiourea were added sequentially to deionized water and magnetically stirred for 10 minutes until completely dissolved. Then, citric acid was added and stirred for 5 minutes until dissolved. Next, rGo dispersion was added dropwise and stirred for 5 minutes. The pH of the solution was adjusted to 5.0 with dilute hydrochloric acid to obtain the hydrothermal precursor solution. In this step, polyethylene glycol monolaurate and CTAB were not added, and the concentrations and proportions of other reagents were exactly the same as in Example 1.

[0077] S2: First, ultrasonically clean the 2cm×3cm sheet carbon cloth substrate with anhydrous ethanol for 10 minutes, then ultrasonically clean it with deionized water for 10 minutes, and finally place it in a vacuum drying oven and dry it at 50℃ for 30 minutes for later use. Completely immerse the pretreated carbon cloth in the hydrothermal precursor solution of step S1, then transfer it to a polytetrafluoroethylene-lined high-pressure reactor, seal it, and place it in an oven to react at a constant temperature of 180℃ for 12 hours. After the reaction is completed, allow it to cool naturally to room temperature.

[0078] S3: Remove the carbon cloth from the reactor and ultrasonically clean it three times with deionized water for 5 minutes each time to remove residual impurities and unreacted reagents on the surface. Then place it in a vacuum drying oven and dry it at 60℃ and -0.08MPa for 12 hours to obtain the SnS2-based composite electrode.

[0079] Comparative Example 2: This comparative example provides a method for preparing a SnS2-based composite electrode. The difference from Example 1 is that in step S1, the amount of CTAB added is 0, and the amount of polyethylene glycol monolaurate added is the sum of polyethylene glycol monolaurate and CTAB in Example 1.

[0080] Comparative Example 3: This comparative example provides a method for preparing a SnS2-based composite electrode. The difference from Example 1 is that in step S1, the pH value of the solution is adjusted to 5.5 to obtain an acidic mixed system.

[0081] In step S2 of this comparative example, severe turbidity was observed in the solution, which could not be clarified even after adding hydrochloric acid. This is because, under the condition of a weakly acidic mixture, citric acid cannot effectively complex Sn. 2+ This led to Sn 2+ Severe hydrolysis.

[0082] Comparative Example 4: This comparative example provides a method for preparing a SnS2-based composite electrode, comprising the following steps: Perform the same steps S1-S4 as in Example 1 to prepare a clear, pale yellow precursor solution. Stir at room temperature in the dark for 20 minutes, then continue stirring for 12 hours to allow Sn to mature. 2+ The SnS2 / rGo composite powder was generated by reacting fully with thiourea. Then, it was centrifuged at 8000 r / min for 10 min, washed three times with deionized water, and vacuum dried at 50℃ for 12 h to obtain the SnS2 / rGo composite powder.

[0083] Take 0.1g of SnS2 / rGo composite powder, add 0.01g of polyvinylidene fluoride and 0.005g of acetylene black, and add a small amount of N-methylpyrrolidone, then grind into a uniform slurry. Coat the slurry uniformly onto the surface of pretreated carbon cloth, controlling the coating thickness to 5-10μm. Place the coated carbon cloth in a vacuum drying oven and dry at 50℃ for 12h to obtain the SnS2-based composite electrode.

[0084] Testing revealed that the SnS2-based composite electrode products prepared in Examples 1-4 had SnS2 nanoparticles with a particle size of 5-20 nm, exhibiting uniform particle size and no obvious agglomeration. Furthermore, by mass percentage, each SnS2-based composite electrode product prepared in Examples 1-4 comprised 94.5-96.0% carbon cloth substrate, 3.0-4.0% SnS2, and 0.3-0.5% reduced graphene oxide, with the remainder being residual components. These residual components primarily originated from surfactants, dispersants, and complexing agents used in the preparation process, and their content was extremely low, approximately 0.2-0.5%, not affecting the electrochemical performance of the electrode. The above product composition data indicates that Examples 1-4 successfully achieved effective loading of the active material SnS2 and the conductive component rGO on the carbon cloth substrate, with the content and distribution of the active material within the optimized range.

[0085] The SnS2-based composite electrodes prepared in Examples 1-4 and Comparative Examples 1-4 were assembled into single vanadium redox flow batteries for electrochemical performance testing. The performance of each example and comparative example is analyzed below based on the test results.

[0086] Figure 1 The efficiency-cycle results of the SnS2-based composite electrode prepared in Example 1 are shown in the figure. Figure 1 It can be seen that the electrode in Example 1 operates at 200 mA·cm⁻¹ -2 At a current density of [value missing], the coulombic efficiency is 98.0%, the voltage efficiency is 87.2%, and the energy efficiency is 85.4%. It is worth noting that from 110 mA·cm [value missing], [efficiency missing]. -2 Up to 350mA·cm -2Its coulombic efficiency remains above 98% over a wide current density range, demonstrating excellent electrochemical reversibility and rate performance.

[0087] Figure 2 The efficiency-cycle results are shown in the graph for the SnS2-based composite electrode prepared in Example 2. Figure 2 It can be seen that the sample in Example 2 at 200 mA·cm -2 At the given current density, the coulombic efficiency is 98.0%, the voltage efficiency is 87.0%, and the energy efficiency is 85.3%. These efficiency indicators are similar to those of Example 1, and the coulombic efficiency also remains above 98% over a wide current density range.

[0088] The efficiency test results of the electrodes prepared in Examples 3 and 4 are basically consistent with those in Examples 1-2. At 200 mA·cm⁻¹ -2 At current densities of 110-350 mA·cm⁻¹, the coulombic efficiency of Example 3 was 97.9%, the voltage efficiency was 86.8%, and the energy efficiency was 85.0%; the coulombic efficiency of Example 4 was 98.1%, the voltage efficiency was 87.1%, and the energy efficiency was 85.2%. Furthermore, Examples 3-4 achieved this at current densities of 110-350 mA·cm⁻¹. -2 The coulombic efficiency remained around 98% across the current density range, significantly better than the ratios.

[0089] Figure 3 The efficiency-cycle results of the SnS2-based composite electrode prepared for Comparative Example 1 are shown in the figure. Figure 3 It can be seen that the sample of Comparative Example 1 at 200 mA·cm -2 At the specified current density, the coulombic efficiency was only 95.4%, the voltage efficiency was 86.7%, and the energy efficiency was 82.7%, all significantly lower than those of Examples 1-4. This indicates that the room-temperature strongly acidic compound system and one-step in-situ impregnation process used in this invention can significantly improve the overall electrochemical performance of the electrode compared to the existing mainstream high-temperature hydrothermal preparation methods.

[0090] Figure 4 The efficiency-cycle results of the SnS2-based composite electrode prepared for Comparative Example 2 are shown in the figure. Figure 4 It can be seen that the sample in Comparative Example 2 at 200 mA·cm -2 At the specified current density, the coulombic efficiency was 95.8%, the voltage efficiency was 86.5%, and the energy efficiency was 82.8%, significantly lower than those in Examples 1-4. This indicates that the surfactant and dispersant compound system used in this invention has significant technical advantages over single reagents. The compound system can more effectively regulate the nucleation and growth process of SnS2, thereby obtaining better electrode performance.

[0091] Figure 5The efficiency-cycle results of the SnS2-based composite electrode prepared for Comparative Example 3 are shown in the figure. Figure 5 It can be seen that the sample of Comparative Example 3 at 200 mA·cm -2 At the specified current density, the coulombic efficiency was 97.4%, the voltage efficiency was 86.4%, and the energy efficiency was 84.2%. Although the coulombic efficiency was slightly improved compared to Comparative Examples 1-2, the voltage efficiency and energy efficiency were still significantly lower than those of Examples 1-4. Furthermore, during the preparation process of Comparative Example 3, citric acid could not effectively complex Sn under weakly acidic conditions. 2+ This led to Sn 2+ Severe hydrolysis resulted in a large amount of precipitation in the solution, making it impossible to form a clear precursor solution. Ultimately, a large amount of blocky precipitate formed on the surface of the carbon cloth, preventing the formation of a uniform active composite layer. This demonstrates that the strongly acidic system used in this invention is one of the key technical conditions for achieving uniform in-situ loading of SnS2.

[0092] Figure 6 The efficiency-cycle results are shown in the graph for the SnS2-based composite electrode prepared in Comparative Example 4. Figure 6 It can be seen that the sample in Comparative Example 4 at 200 mA·cm -2 At the specified current density, the coulombic efficiency was 96.9%, the voltage efficiency was 86.8%, and the energy efficiency was 84.2%, all significantly lower than those of Examples 1-4. Comparative Example 4 employed a non-in-situ coating route consistent with existing technologies, requiring the addition of an insulating binder PVDF and a conductive agent acetylene black. This not only increased the number of process steps but also increased the interfacial resistance due to the binder. The active material and the carbon cloth substrate only had a physical bond, limiting both the voltage and energy efficiencies of the electrode. This demonstrates that the in-situ growth loading method used in this invention has significant technical advantages over the non-in-situ coating loading method.

[0093] Figure 7 The SnS2-based composite electrodes prepared for each embodiment and comparative example were subjected to 200 mA·cm⁻¹. -2 Comparison of voltage efficiency and cyclic stability under current density.

[0094] from Figure 7 It can be seen that the electrodes prepared in Examples 1 and 2 maintained good voltage efficiency stability during 300 charge-discharge cycles, with almost no voltage efficiency degradation. Furthermore, the cycle stability test results of Examples 3 and 4 were basically consistent with those of Examples 1-2, maintaining stable voltage efficiency without significant degradation trend within 300 cycles. These results demonstrate that the method of the present invention establishes a strong chemical interface bond between SnS2 and the carbon cloth substrate through in-situ growth, preventing the active material from easily detaching during long cycles and resulting in excellent electrode structural stability.

[0095] In stark contrast, the samples in Comparative Examples 1 and 4 exhibited significant voltage efficiency degradation within 300 cycles, with the degradation rate increasing progressively with the number of cycles. The degradation was even more severe in Comparative Examples 2 and 3, with a significant decrease in voltage efficiency observed after only 120 cycles.

[0096] The above comparison results of cycle stability fully demonstrate that the present invention adopts a strong acid compound system combined with a one-step in-situ impregnation process at room temperature, which not only simplifies the preparation process, but also fundamentally solves the problem of weak bonding between active material and substrate and easy detachment in traditional methods, and significantly improves the structural stability and performance durability of the electrode under long-term operation conditions.

[0097] Based on the above test results, the SnS2-based composite electrodes prepared in Examples 1-4 of this invention are significantly superior to the comparative examples in terms of coulombic efficiency, voltage efficiency, energy efficiency, and long-cycle stability, thus verifying the effectiveness of the technical solution of this invention.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing SnS2-based composite electrode, characterized in that, Includes the following steps: S1: Provide a mixed aqueous solution containing surfactant and dispersant, and adjust the pH of the mixed aqueous solution to 1.1-1.3 to obtain an acidic mixed system; S2: Add a complexing agent and a tin source to the acidic mixture to obtain a tin source mixture; S3: Add sulfur source and reduced graphene oxide to tin source mixture to obtain reaction precursor solution; S4: The reaction precursor solution is stirred and matured under light-protected conditions to obtain a matured precursor solution; S5: Immerse the carbon cloth substrate in the aging precursor solution at 20-30℃ and in the dark for impregnation treatment, so that the tin source and sulfur source react in situ on the surface of the carbon cloth substrate to generate SnS2, which is then loaded onto the carbon cloth substrate together with the reduced graphene oxide. S6: After impregnation, a drying process is performed to obtain the SnS2-based composite electrode.

2. The method of claim 1, wherein the SnS2-based composite electrode is prepared by the steps of: In step S1, the surfactant is polyethylene glycol monolaurate or fatty alcohol polyoxyethylene ether, and the dispersant is hexadecyltrimethylammonium bromide, sodium dodecyl sulfate or polyvinylpyrrolidone. The mass ratio of surfactant to dispersant is 1:1-3:

1. The pH of the mixed aqueous solution is adjusted to 1.1-1.3 by concentrated hydrochloric acid.

3. The method of claim 1, wherein the SnS2-based composite electrode is prepared by the steps of: In step S2, the complexing agent is citric acid, the tin source is stannous chloride, and the amount of citric acid added in the tin source mixture is 1.5-2 g / L; the molar ratio of citric acid to stannous chloride is (0.5-0.8):

1.

4. The method for preparing the SnS2-based composite electrode according to claim 1, characterized in that, In step S3, the sulfur source is thiourea; the molar ratio of thiourea to the tin source in step S2 is (2.5-4):

1.

5. The method for preparing the SnS2-based composite electrode according to claim 1, characterized in that, In step S3, reduced graphene oxide is added in the form of a dispersion, the concentration of which is 0.5-1.5 g / L, and the volume ratio of the added reduced graphene oxide dispersion to the mixed aqueous solution is 1:(600-1000).

6. The method for preparing the SnS2-based composite electrode according to claim 1, characterized in that, In step S4, the stirring and maturation process takes 15-30 minutes.

7. The method for preparing the SnS2-based composite electrode according to claim 1, characterized in that, In step S5, the immersion treatment time is 2.5-3.5 hours.

8. The method for preparing the SnS2-based composite electrode according to claim 1, characterized in that, In step S6, after impregnation, the SnS2-based composite electrode is dried in a vacuum at 40-60℃ and -0.08MPa to -0.09MPa for 10-14 hours in the dark to obtain the SnS2-based composite electrode.

9. A SnS2-based composite electrode, characterized in that, It is prepared by the preparation method according to any one of claims 1-8; The SnS2-based composite electrode comprises, by mass percentage, 94.5-96.0% carbon cloth substrate, 3.0-4.0% SnS2, 0.3-0.5% reduced graphene oxide, with the remainder being residual components; the residual components include surfactants, dispersants, and complexing agents.

10. An electrode prepared by the method of any one of claims 1-8, or the SnS2-based composite electrode of claim 9, in a vanadium redox flow battery, a zinc-bromine flow battery, an iron-chromium flow battery, a lithium-ion battery, a sodium-ion battery, a potassium-ion battery, an asymmetric supercapacitor, a lithium-sulfur battery, a water electrolysis hydrogen production device, a carbon dioxide reduction catalyst, or an electrochemical sensor.

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