Carbon cloth-supported heterostructured material, and preparation method therefor and use thereof

Abstract

The present application provides a carbon cloth-supported heterostructured material, and a preparation method therefor and a use thereof. The carbon cloth-supported heterostructured material comprises a carbon cloth and a bimetallic sulfide salt supported on the surface of the carbon cloth. The carbon cloth has a carbon fiber conductive network, and the bimetallic sulfide salt is grown in the form of shingle-like nanosheets on the surface of the carbon fiber conductive network, so as to form a three-dimensional network structure. The metal in the bimetallic sulfide salt comprises zinc. In the material of the present application, the bimetallic sulfide salt is uniformly grown in the form of shingle-like nanosheets on the carbon fiber conductive network in the carbon cloth, the nanosheets are connected to each other and cross each other to form the three-dimensional network structure, more active sites are introduced, and the electrical conductivity is improved, thereby facilitating implementation of fast kinetics that avoids solid-state diffusion and promotes ion diffusion. The carbon cloth-supported heterostructured material of the present application can significantly improve the rate performance, specific capacity and cycle performance of a composite negative electrode.

Description

Carbon cloth-supported heterostructure materials, their preparation methods and applications

[0001] This application claims priority to Chinese patent application 2024119064390, filed on December 23, 2024. The entire contents of the aforementioned Chinese patent application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of lithium-ion battery technology, and more specifically, to a carbon cloth-supported heterostructure material, its preparation method, and its application. Background Technology

[0003] As is well known, graphite, as the main commercial anode material in lithium-ion batteries, suffers from poor stability due to its layered structure. After prolonged charge-discharge cycles, its structure is prone to collapse, leading to a significant decrease in specific capacity and a substantial reduction in energy storage life. The development of novel anode materials with high energy density has never ceased.

[0004] Inserting carbon-based anodes (such as hard carbon) can relatively improve electrochemical performance. However, their output capacity is below 300 mAh·g. -1 This limitation restricts its practical application in lithium-ion batteries. Transition metal sulfides, as potential electrode materials, possess a higher theoretical specific capacity than intercalated carbonaceous materials due to their storage mechanism based on multiple electron transfer. Compared to oxides, transition metal sulfides generally exhibit superior electronic conductivity and structural stability.

[0005] However, the cycling performance of transition metal sulfides remains unsatisfactory due to slow kinetics and volume changes during lithiation / delithiation. To alleviate these problems, researchers have made significant efforts, and combining nanostructured transition metal sulfides with highly conductive scaffolds is considered a common and effective strategy, which can not only mitigate the Li-induced degradation of lithium but also improve the overall performance of transition metals. + Structural changes caused by insertion / extraction can also improve electronic conductivity, thereby improving the electrochemical performance of lithium-ion battery anodes. However, their improvement on the rate performance, specific capacity and cycle performance of anodes is still limited, making it difficult to achieve large-scale commercial application. Summary of the Invention

[0006] The main objective of this application is to provide a carbon cloth-supported heterostructure material, its preparation method and application, in order to solve the problems of poor rate performance, specific capacity and cycle performance of lithium-ion battery anodes in the prior art.

[0007] To achieve the above objectives, according to one aspect of this application, a carbon cloth-supported heterostructure material is provided, comprising carbon cloth and a bimetallic sulfide salt supported on the surface of the carbon cloth. The carbon cloth has a carbon fiber conductive network, and the bimetallic sulfide salt is grown on the surface of the carbon fiber conductive network in the form of tile-like nanosheets to form a three-dimensional network structure. The metal in the bimetallic sulfide salt includes zinc. The carbon cloth-supported heterostructure material of this application can significantly improve the rate performance, specific capacity, and cycle performance of the composite anode.

[0008] Furthermore, the bimetallic sulfide salts include one or more of nickel-zinc sulfide, iron-zinc sulfide, cobalt-zinc sulfide, and aluminum-zinc sulfide. These bimetallic sulfide salts have higher theoretical capacities and provide more active sites, thereby improving specific capacity.

[0009] Furthermore, by weight percentage, carbon cloth accounts for 85-88% of the carbon cloth-supported heterostructure material, and bimetallic sulfide salt accounts for 12-15% of the carbon cloth-supported heterostructure material, which can better achieve a balance between conductivity and electrochemical activity.

[0010] Furthermore, the maximum length of a single tile-like nanosheet is 2–6 μm; and / or the diameter of the carbon fibers in the carbon fiber conductive network is 5–7 μm. Based on the synergistic effect of carbon fibers and nanosheets of these sizes, a more efficient three-dimensional conductive framework can be formed, reducing the transmission path and maintaining a more stable electrochemical reaction even at high current densities, resulting in significantly improved cycle stability.

[0011] According to another aspect of this application, a method for preparing the carbon cloth-supported heterostructure material described above is provided, comprising the following steps: Step S1, annealing the carbon cloth to obtain a pretreated carbon cloth; Step S2, mixing zinc salt, a second metal salt, urea, hexamethylenetetramine, and water to obtain a metal solution; immersing the pretreated carbon cloth in the metal solution to perform a hydrothermal reaction to obtain a precursor; Step S3, immersing the precursor in an aqueous solution of sulfide to perform a sulfidation reaction to obtain the carbon cloth-supported heterostructure material. The above preparation method is simple and easy to operate. The abundant surface area of ​​the nanosheets in the prepared carbon cloth-supported heterostructure material can provide more active sites for electrochemical reactions, thereby significantly improving the rate performance, specific capacity, and cycle performance of the composite anode material.

[0012] Further, in step S1, the annealing temperature is 350–450°C, and the time is 1.5–2.5 h. Preferably, before annealing, step S1 further includes a step of sequentially cleaning and drying the carbon cloth: ultrasonically cleaning the carbon cloth with acetone for 50–70 min, then ultrasonically cleaning it with a mixture of ethanol and water for 50–70 min, and then drying it to dryness at 70–90°C. Under the above conditions, the microstructure of the carbon cloth can be further optimized, its conductivity and thermal stability can be enhanced, and the repair of surface defects can be promoted. This improves the electron transport efficiency and structural integrity of the material, which is beneficial for the rapid transport and storage of lithium ions, thereby significantly improving rate performance and cycle performance.

[0013] Further, in step S2, the zinc salt includes zinc nitrate hexahydrate, and the second metal salt includes nickel chloride hexahydrate, iron chloride, cobalt chloride, or aluminum chloride; preferably, the weight ratio of zinc salt to the second metal salt is 1:(2-3); and / or the weight ratio of urea to hexamethylenetetramine is 1:(0.25-0.5); preferably, the weight ratio of zinc salt to urea is 1:(6-7); and / or the hydrothermal reaction temperature is 110-130°C, and the time is 5-7 h; preferably, step S2 further includes the following steps: washing the precursor with a mixture of ethanol and water for 50-70 min, and then drying it to dryness at 70-90°C. This can better promote the uniform deposition of bimetallic sulfides to form a dense and stable nanostructure, increase active sites, optimize lithium-ion storage capacity, and thus improve specific capacity.

[0014] Further, in step S3, the sulfide includes one or more of sodium sulfide, sodium sulfide nonahydrate, and thiourea; preferably, the weight ratio of the sum of the zinc salt and the second metal salt to the weight of the sulfide is 1:(0.65–0.75); and / or the sulfidation reaction temperature is 150–170°C, and the time is 5–7 h; preferably, step S3 further includes the following steps: washing the carbon cloth-supported heterostructure material with a mixture of ethanol and water for 50–70 min, and then drying it to dryness at 70–90°C. These conditions can further promote the complete conversion of the bimetallic sulfide in the sulfidation reaction, forming a highly crystalline, structurally stable heterostructure nanostructure to increase lithium-ion storage sites and significantly improve specific capacity.

[0015] According to another aspect of this application, a lithium-ion battery anode is provided, comprising the carbon cloth-supported heterostructure material described above. The anode of this application achieves a comprehensive performance improvement, possessing high energy density, excellent cycle life, and fast charge / discharge capability.

[0016] According to another aspect of this application, a lithium-ion battery is provided, including the lithium-ion battery negative electrode described above, which has significantly improved rate performance, specific capacity and cycle performance.

[0017] Using the technical solution of this application, bimetallic sulfide salts are uniformly grown as tile-like nanosheets on a carbon fiber conductive network within carbon cloth. The nanosheets are interconnected and intersecting, forming a three-dimensional network structure. The abundant open spaces between the nanosheets promote electrolyte penetration and lithiation of the electrode. The tile-like nanosheets also introduce more active sites, and the significant gaps between the nanosheets greatly increase the contact area between the material and the electrolyte, improving conductivity and providing more active sites for electrochemical reactions. Bimetallic sulfide salts also combine the advantages of multi-component and multi-phase structures, generating sufficient boundaries and small crystal domains, which helps to achieve rapid kinetics that avoid solid-state diffusion and promote ion diffusion. The carbon cloth-supported heterostructure material of this application can significantly improve the rate performance, specific capacity, and cycle performance of the composite anode. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0019] Figure 1 shows a SEM image (5 μm) of the carbon cloth-supported heterostructure material according to Embodiment 1 of this application;

[0020] Figure 2 shows the XRD diffraction pattern of the carbon cloth-supported heterostructure material according to Embodiment 1 of this application;

[0021] Figure 3 shows the cycling performance curve of the carbon cloth-supported heterostructure material according to Embodiment 1 of this application;

[0022] Figure 4 shows a structural diagram of a soft-pack battery according to Embodiment 1 of this application;

[0023] Figure 5 shows the cycle performance curve of the pouch cell according to Embodiment 1 of this application;

[0024] Figure 6 shows a SEM image (20 μm) of the carbon cloth-supported heterostructure material according to Example 1 of this application. Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] As described in the background section of this application, existing technologies suffer from poor rate performance, specific capacity, and cycle performance of lithium-ion battery anodes. To address these issues, in a typical embodiment of this application, a carbon cloth-supported heterostructure material is provided, comprising carbon cloth and a bimetallic sulfide salt loaded on the surface of the carbon cloth. The carbon cloth has a carbon fiber conductive network, and the bimetallic sulfide salt is grown on the surface of the carbon fiber conductive network in the form of tile-like nanosheets to form a three-dimensional network structure. The metal in the bimetallic sulfide salt includes zinc.

[0027] Among them, the "tiled" structure refers to the orderly distribution of nanosheets formed by bimetallic sulfide salts on the surface of the carbon fiber conductive network, with each nanosheet partially covering the adjacent nanosheets.

[0028] The composite material of this application comprises carbon cloth, which has a carbon fiber conductive network as a substrate material; a bimetallic sulfide salt is uniformly grown on the carbon fiber conductive network in the form of tile-like nanosheets, which are interconnected and intersecting to form a three-dimensional network structure. The dimensions of both the bimetallic sulfide salt and the carbon fiber conductive network are on the micrometer scale.

[0029] Taking the bimetallic sulfide salt using nickel-zinc sulfide (ZnNi2S4) as an example, the loading mechanism of this application is as follows: a ZnNi precursor is formed on the surface of a carbon fiber rod, and then the ZnNi precursor gradually aggregates to form a dense nanosheet layer. After vulcanization, tile-like bimetallic sulfide salt nanosheets are grown on the carbon fiber conductive network. The material of this application has a carbon cloth conductive network loaded with a ZnNi2S4 3D foam nanosheet (flower) array, wherein the nanosheets are interconnected and intersected to form a three-dimensional network structure, and the voids can be clearly observed. A SEM image of the carbon cloth loaded heterostructure material of one embodiment is shown in Figure 1.

[0030] Specifically, carbon cloth primarily provides a stable conductive substrate and three-dimensional framework to promote electron conduction, ensuring high conductivity and thus significantly improving rate performance. The abundant open spaces between the nanosheets facilitate electrolyte penetration and promote electrode lithiation. The tile-like nanosheets introduce more active sites, and the significant gaps between them greatly increase the contact area with the electrolyte, improving conductivity and providing more active sites for electrochemical reactions. Bimetallic sulfide salts, such as ZnNi₂S₄, generally have a spinel structure, with Zn and Ni located at octahedral and tetrahedral positions, respectively. This combines the advantages of multi-component and multi-phase structures. The presence of these multiphase structures in ZnNi₂S₄ generates sufficient boundaries and small crystal domains, helping to circumvent solid-state diffusion and promoting rapid ion diffusion kinetics.

[0031] When the bimetallic sulfide salt includes zinc, it is more conducive to the formation of tile-like nanosheets with specific properties to improve electrical performance and make the structure more stable. Furthermore, zinc can be loaded onto the carbon cloth surface as a zinc-metal precursor during the formation process, subsequently forming nanosheets with chemical bonds to the carbon cloth. Compared to conventional physical coating methods, chemical bonding significantly enhances the connection strength between the bimetallic sulfide salt and the carbon cloth, making it less prone to detachment during use.

[0032] Furthermore, compared to monometallic sulfide salts such as NiS and ZnS, bimetallic sulfide salts such as ZnNi2S4 contain Ni 2+ and Zn 2+ The presence of carbon cloth provides it with more redox reaction sites and multi-electron reaction mechanisms, thus resulting in higher electrochemical activity. In summary, the carbon cloth-supported heterostructure material of this application can significantly improve the rate performance, specific capacity, and cycle performance of the composite anode.

[0033] In a preferred embodiment, the bimetallic sulfide salt includes one or more of nickel-zinc sulfide, iron-zinc sulfide, cobalt-zinc sulfide, and aluminum-zinc sulfide. These bimetallic sulfide salts possess higher theoretical capacity and provide more active sites, thereby improving specific capacity. Simultaneously, the unique three-dimensional foam nanoflower structure they form further increases the contact area between the electrode and the electrolyte, promoting rapid electron and ion transport and enhancing rate performance. The bimetallic elements also optimize the electronic structure of the material, improve electronic conductivity, and reduce polarization during electrochemical reactions, thereby enhancing cycle stability and improving performance consistency over long-term use. Furthermore, these bimetallic sulfide salts are more conducive to synergistic effects with carbon cloth conductive networks to further alleviate volume expansion caused during lithiation / delithiation, thereby further enhancing cycle performance.

[0034] To better achieve a balance between conductivity and electrochemical activity, in a preferred embodiment, carbon cloth accounts for 85-88% of the carbon cloth-supported heterostructure material by weight, and bimetallic sulfide salt accounts for 12-15%. The carbon fiber conductive network with these proportions serves as a substrate, further improving structural stability, better mitigating stress caused by volume changes during cycling, and enhancing cycling performance. The remaining proportion of bimetallic sulfide salt, as the active material, leverages its high theoretical capacity and multi-electron reaction characteristics to further improve the specific capacity of the composite anode, increase active sites, promote rapid lithium-ion insertion and extraction, and ultimately further optimize rate performance and cycling stability.

[0035] In a preferred embodiment, the maximum length of a single tile-like nanosheet is 2–6 μm; and / or the diameter of the carbon fiber in the carbon fiber conductive network is 5–7 μm. The aforementioned small size of the nanosheets is more conducive to increasing the surface area, providing more abundant active sites, accelerating lithium ion insertion and extraction, and significantly improving specific capacity. Simultaneously, the micron-sized carbon fibers not only serve as a conductive network but also further promote sufficient electrolyte penetration and efficient ion transport, thereby optimizing rate performance. Based on the synergistic effect of the carbon fibers and nanosheets of the aforementioned sizes, a more efficient three-dimensional conductive framework can be formed, reducing transport paths and maintaining a more stable electrochemical reaction even at high current densities, resulting in significantly improved cycle stability.

[0036] In another typical embodiment of this application, a method for preparing the carbon cloth-supported heterostructure material described above is also provided, comprising the following steps: Step S1, annealing the carbon cloth to obtain pretreated carbon cloth; Step S2, mixing zinc salt, a second metal salt, urea, hexamethylenetetramine and water to obtain a metal solution; immersing the pretreated carbon cloth in the metal solution to perform a hydrothermal reaction to obtain a precursor; Step S3, immersing the precursor in an aqueous solution of sulfide to perform a sulfidation reaction to obtain the carbon cloth-supported heterostructure material.

[0037] The formation of bimetallic sulfide salt nanosheets can be explained by the Kirkendall effect. Specifically, this application first anneales carbon cloth to generate oxygen-containing functional groups on its surface, improving its hydrophilicity, and obtains pretreated carbon cloth; then, zinc salt, a second metal salt, urea, hexamethylenetetramine, and water are mixed to obtain a metal solution, and the pretreated carbon cloth is immersed in the metal solution and subjected to a hydrothermal reaction. Taking ZnNi2S4 nanosheets as an example, the mechanism is that urea hydrolyzes to produce carbon dioxide, which drives the metal ions to diffuse outward, forming a ZnNi-precursor on the surface of the carbon fiber rod. The ZnNi-precursor gradually aggregates to form a dense nanosheet layer, obtaining the precursor.

[0038] Finally, the precursor was immersed in an aqueous solution of sulfide and subjected to a sulfidation reaction. The high-temperature pyrolysis of the sulfide led to the formation of S... 2- Release of ions, S 2- The ions react with the ZnNi- precursor to form the corresponding ZnNi2S4, which inherits the precursor morphology well, acting as a physical barrier coating the carbon fibers. As the reaction proceeds, due to the Zn... 2+ and Ni 2+ The diffusion rate relative to S 2-The growth rate of the nanosheets varies, leading to the gradual transformation of the ZnNi precursor into foam-like ZnNi2S4 nanosheets. This results in highly representative morphologies of the ZnNi2S4 nanosheets, yielding a carbon cloth-supported heterostructure material. The above preparation method is simple and easy to operate. The abundant surface area of ​​the nanosheets in the prepared carbon cloth-supported heterostructure material provides more active sites for electrochemical reactions, thereby significantly improving the rate performance, specific capacity, and cycle performance of the composite anode material.

[0039] In a preferred embodiment, in step S1, the annealing temperature is 350–450°C, and the time is 1.5–2.5 h. Before annealing, step S1 further includes a step of sequentially cleaning and drying the carbon cloth: the carbon cloth is ultrasonically cleaned with acetone for 50–70 min, then ultrasonically cleaned with a mixture of ethanol and water for 50–70 min, and then dried at 70–90°C. The sequential cleaning with acetone and ethanol effectively removes organic impurities and residues from the surface of the carbon cloth, improving the purity and surface activity of the material, providing a clean substrate for the subsequent uniform growth of nanosheets, and promoting good contact and bonding between the active material and the conductive network. The annealing treatment under the above conditions can further optimize the microstructure of the carbon cloth, enhance its conductivity and thermal stability, while promoting the repair of surface defects, improving the electron transport efficiency and structural integrity of the material, which is beneficial for the rapid transport and storage of lithium ions, thereby significantly improving rate performance and cycle performance.

[0040] To better promote the uniform deposition of bimetallic sulfides to form a dense and stable nanostructure, increase active sites, optimize lithium-ion storage capacity, and thus improve specific capacity, in a preferred embodiment, in step S2, the zinc salt includes zinc nitrate hexahydrate, and the second metal salt includes nickel chloride hexahydrate, iron chloride, cobalt chloride, or aluminum chloride; preferably, the weight ratio of zinc salt to the second metal salt is 1:(2-3); and / or the weight ratio of urea to hexamethylenetetramine is 1:(0.25-0.5); preferably, the weight ratio of zinc salt to urea is 1:(6-7); and / or the hydrothermal reaction temperature is 110-130°C, and the time is 5-7 h; preferably, step S2 further includes the following steps: washing the precursor with a mixture of ethanol and water for 50-70 min, and then drying it to dryness at 70-90°C. When the ratio of urea to hexamethylenetetramine and the ratio of urea to zinc salt are within the above-mentioned ranges, it is more conducive to improving the growth rate and morphology of precursors and nanosheets, constructing more efficient lithium-ion transport channels, and thus enhancing rate performance. The above-mentioned hydrothermal reaction conditions are more conducive to the high-quality formation of nanostructures, improving the electronic conductivity and structural consistency of the material, thereby improving cycle performance. The washing and drying steps can effectively remove byproducts, reduce the negative impact of impurities on electrochemical performance, and further improve the purity and reactivity of the material.

[0041] In a preferred embodiment, in step S3, the sulfide includes one or more of sodium sulfide, sodium sulfide nonahydrate, and thiourea; preferably, the weight ratio of the sum of the zinc salt and the second metal salt to the weight of the sulfide is 1:(0.65-0.75); and / or the sulfidation reaction temperature is 150-170°C, and the time is 5-7 hours; preferably, step S3 further includes the following steps: washing the carbon cloth-supported heterostructure material with a mixture of ethanol and water for 50-70 minutes, and then drying it to dryness at 70-90°C. Within the above material ratio range, the complete conversion of the bimetallic sulfide in the sulfidation reaction can be further promoted, forming a highly crystalline, structurally stable heterostructure nanostructure to increase lithium-ion storage sites and significantly improve specific capacity. The above sulfidation reaction parameters can further improve the depth and uniformity of the sulfidation process, optimize the morphology and size of the nanostructure, construct fast ion transport channels, and enhance rate performance. In addition, cleaning and drying with ethanol and water can effectively remove residual reaction byproducts, improve the surface cleanliness and reactivity of the material, reduce the polarization of the electrochemical reaction, and thus further improve cycle performance.

[0042] In another typical embodiment of this application, a lithium-ion battery anode is also provided, comprising the carbon cloth-supported heterostructure material described above. In this anode, the three-dimensional stable structure of the carbon cloth conductive network provides an efficient electron conduction path, significantly enhancing electrode conductivity, increasing the rate of electrochemical reactions, and improving the battery's rate performance. Secondly, the supported bimetallic sulfide nanosheets increase electrochemical active sites, significantly improving lithium-ion storage capacity, thereby increasing the battery's specific capacity. Furthermore, the intersecting three-dimensional network structure of the nanosheets promotes electrolyte penetration and uniform lithium-ion diffusion, reducing structural stress during cycling and greatly enhancing the material's cycle stability. Combining these advantages, the anode of this application achieves a comprehensive performance improvement, possessing high energy density, excellent cycle life, and fast charge / discharge capability.

[0043] In another typical embodiment of this application, a lithium-ion battery is also provided, including the lithium-ion battery negative electrode described above, which has significantly improved rate performance, specific capacity and cycle performance.

[0044] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0045] Example 1

[0046] A carbon cloth-supported ZnNi2S4 material (CFC@ZnNi2S4) comprises, by weight percentage, 87% carbon cloth and 13% bimetallic sulfide salt. The preparation method includes the following steps:

[0047] Step S1: First, ultrasonically clean the carbon cloth with the organic solvent acetone for 60 minutes, then ultrasonically clean it with ethanol and deionized water for 60 minutes. Place the carbon cloth in an 80℃ drying oven for drying. Finally, remove the dried carbon cloth and place it in a muffle furnace for annealing at 400℃ for 2 hours to obtain pretreated carbon cloth.

[0048] Step S2: 0.297g Zn(NO3)2·6H2O, 0.713g NiCl2·6H2O, 2g urea, and 0.75g hexamethylenetetramine were dissolved in a reactor containing 75ml of deionized water. The pretreated carbon cloth was immersed in the reactor, and the reactor was heated to 120℃ and maintained at this temperature for 6 hours. After cooling, the carbon cloth was removed from the reactor and washed with ethanol and deionized water to remove residual chemical reagents from its surface. Finally, it was placed in a vacuum drying oven at 80℃ until completely dried to obtain the precursor.

[0049] Step S3: Dissolve 0.72g of sodium sulfide in a reactor containing 75mL of deionized water, and then add the precursor back in. Start the reactor and heat it to 160℃, maintaining this temperature for 6 hours. After cooling, remove the carbon cloth sample that has undergone hydrothermal treatment and wash it with ethanol and deionized water to remove residual chemical reagents from the surface of the carbon cloth. Finally, place it in a vacuum drying oven at 80℃ until completely dry to obtain the carbon cloth-supported heterostructure material.

[0050] Example 2

[0051] The difference from Example 1 is that a carbon cloth-supported ZnFe2S4 material (CFC@ZnFe2S4) is used; Step S2: 0.297g Zn(NO3)2·6H2O, 0.784g FeCl2·6H2O, 2g urea, and 0.75g hexamethylenetetramine are dissolved in a reactor containing 75ml of deionized water. The pretreated carbon cloth is immersed in the reactor, and the reactor is heated to 120°C and maintained at this temperature for 6 hours. After cooling, the carbon cloth is removed from the reactor and washed with ethanol and deionized water to remove residual chemical reagents from the surface of the carbon cloth. Finally, it is placed in a vacuum drying oven at 80°C until completely dried to obtain the precursor.

[0052] Example 3

[0053] The difference from Example 1 is that a carbon cloth-supported ZnCo2S4 material (CFC@ZnCo2S4) is used; Step S2: 0.297g Zn(NO3)2·6H2O, 0.689g CoCl2·6H2O, 2g urea, and 0.75g hexamethylenetetramine are dissolved in a reactor containing 75ml of deionized water. The pretreated carbon cloth is immersed in the reactor, and the reactor is heated to 120°C and maintained at this temperature for 6 hours. After cooling, the carbon cloth is removed from the reactor and washed with ethanol and deionized water to remove residual chemical reagents from the surface of the carbon cloth. Finally, it is placed in a vacuum drying oven at 80°C until completely dried to obtain the precursor.

[0054] Example 4

[0055] The difference from Example 1 is that a carbon cloth-supported ZnAl2S4 material (CFC@ZnAl2S4) is used; Step S2: 0.297g Zn(NO3)2·6H2O, 0.438g AlCl3·6H2O, 2g urea, and 0.75g hexamethylenetetramine are dissolved in a reactor containing 75ml of deionized water. The pretreated carbon cloth is immersed in the reactor, and the reactor is heated to 120°C and maintained at this temperature for 6 hours. After cooling, the carbon cloth is removed from the reactor and washed with ethanol and deionized water to remove residual chemical reagents from the surface of the carbon cloth. Finally, it is placed in a vacuum drying oven at 80°C until completely dried to obtain the precursor.

[0056] Example 5

[0057] The difference from Example 1 is that in step S1: the carbon cloth is first ultrasonically cleaned with the organic solvent acetone for 50 minutes, and then ultrasonically cleaned with ethanol and deionized water for 50 minutes. The carbon cloth is then placed in a drying oven at 70°C for drying. Finally, the dried carbon cloth is taken out and placed in a muffle furnace for annealing at 350°C for 2.5 hours to obtain pretreated carbon cloth.

[0058] Example 6

[0059] The difference from Example 1 is that in step S1: the carbon cloth is first ultrasonically cleaned with the organic solvent acetone for 70 minutes, and then ultrasonically cleaned with ethanol and deionized water for 70 minutes. The carbon cloth is then placed in a drying oven at 90°C for drying. Finally, the dried carbon cloth is taken out and placed in a muffle furnace for annealing at 450°C for 1.5 hours to obtain pretreated carbon cloth.

[0060] Example 7

[0061] The difference from Example 1 lies in step S2: 0.297g Zn(NO3)2·6H2O, 0.594g NiCl2·6H2O, 1.78g urea, and 0.89g hexamethylenetetramine were dissolved in a reactor containing 75ml of deionized water. The pretreated carbon cloth was immersed in the reactor, and the reactor was heated to 110°C and maintained at this temperature for 7 hours. After cooling, the carbon cloth was removed from the reactor and washed with ethanol and deionized water to remove residual chemical reagents from its surface. Finally, it was placed in a vacuum drying oven at 70°C until completely dried to obtain the precursor.

[0062] Example 8

[0063] The difference from Example 1 lies in step S2: 0.297g Zn(NO3)2·6H2O, 0.861g NiCl2·6H2O, 2.08g urea, and 0.52g hexamethylenetetramine were dissolved in a reactor containing 75ml of deionized water. The pretreated carbon cloth was immersed in the reactor, and the reactor was heated to 130°C and maintained at this temperature for 5 hours. After cooling, the carbon cloth was removed from the reactor and washed with ethanol and deionized water to remove residual chemical reagents from its surface. Finally, it was placed in a vacuum drying oven at 90°C until completely dried to obtain the precursor.

[0064] Example 9

[0065] The difference from Example 1 lies in step S3: 0.66g of sodium sulfide is dissolved in a reactor containing 75mL of deionized water, and the precursor is added again. The reactor is started and heated to 150°C, maintained at this temperature for 7 hours. After cooling, the carbon cloth sample treated with hydrothermal reaction is removed and washed with ethanol and deionized water to remove residual chemical reagents from the surface of the carbon cloth. Finally, it is placed in a vacuum drying oven at 70°C until completely dried to obtain a carbon cloth-supported heterostructure material.

[0066] Example 10

[0067] The difference from Example 1 lies in step S3: 0.76g of sodium sulfide is dissolved in a reactor containing 75mL of deionized water, and the precursor is added again. The reactor is started and heated to 170°C, maintained at this temperature for 5 hours. After cooling, the carbon cloth sample treated with hydrothermal reaction is removed and washed with ethanol and deionized water to remove residual chemical reagents from the surface of the carbon cloth. Finally, it is placed in a vacuum drying oven at 90°C until completely dried to obtain a carbon cloth-supported heterostructure material.

[0068] Example 11

[0069] The difference from Example 1 is that, by weight percentage, carbon cloth accounts for 85% of the carbon cloth-supported heterostructure material, and bimetallic sulfide salt accounts for 15%.

[0070] Example 12

[0071] The difference from Example 1 is that, by weight percentage, carbon cloth accounts for 88% of the carbon cloth-supported heterostructure material, and bimetallic sulfide salt accounts for 12%.

[0072] Comparative Example 1

[0073] The difference from Example 1 is that NiS is loaded on the surface of the carbon cloth.

[0074] Comparative Example 2

[0075] The difference from Example 1 is that ZnS is loaded on the surface of the carbon cloth.

[0076] Comparative Example 3

[0077] The difference from Example 1 is that step S2 uses a one-step hydrothermal method: 0.297g Zn(NO3)2·6H2O, 0.713g NiCl2·6H2O, 0.72g sodium sulfide, 2g urea, and 0.75g hexamethylenetetramine are dissolved in a reactor containing 150ml of deionized water. The pretreated carbon cloth is immersed in the reactor, and the reactor is heated to 160℃ and maintained at this temperature for 6 hours. After cooling, the carbon cloth sample treated by the hydrothermal reaction is taken out and washed with ethanol and deionized water to remove residual chemical reagents from the surface of the carbon cloth. Finally, it is placed in a vacuum drying oven at 80℃ until completely dried to obtain a carbon cloth-supported heterostructure material.

[0078] Performance testing:

[0079] The materials prepared in the above embodiments and comparative examples were applied to the anode of flexible lithium-ion batteries, and performance tests were conducted. The results are shown in Table 1.

[0080] [Carbon cloth supported heterostructure materials]

[0081] Maximum length of a single tile-like nanosheet, diameter of carbon fibers in a carbon fiber conductive network: electron microscopy.

[0082] Carbon cloth percentage and metal sulfide salt percentage: Weigh the pretreated carbon cloth and the carbon cloth-loaded heterostructure material respectively. Carbon cloth percentage = weight of pretreated carbon cloth ÷ weight of carbon cloth-loaded heterostructure material × 100%. Metal sulfide salt percentage = (weight of carbon cloth-loaded heterostructure material - weight of pretreated carbon cloth) ÷ weight of carbon cloth-loaded heterostructure material × 100%.

[0083] Coin-shaped battery

[0084] Lithium-ion battery assembly: Electrochemical testing of carbon cloth-loaded heterostructure materials was conducted using CR2032 coin-shaped batteries. The prepared material was directly used as the working electrode, and lithium foil (lithium sheet) was used as the counter electrode. Both electrodes were cut into 1.2 cm diameter discs, with 0.1 g of ZnNi2S4 loaded on the carbon cloth conductive network. Celgard 2400 was used as the separator, and 1 M LiPF6 was added to ethylene carbonate (EC) / diethyl carbonate (DEC) / dimethyl carbonate (DMC) (volume ratio 1:1:1) as the electrolyte. The battery was assembled in an argon-filled glove box, with H2O and O2 contents maintained below 0.1 ppm.

[0085] The SEM images (5 μm) of the carbon cloth-supported heterostructure material in Example 1 are shown in Figure 1, the SEM image (20 μm) is shown in Figure 6, and the XRD diffraction pattern is shown in Figure 2. Figure 1 shows that the carbon fiber rod is covered with tile-like ZnNi2S4 nanosheets. The nanosheets are interconnected and intersecting, forming a three-dimensional network structure. Figure 2 shows that the diffraction peaks of the sample are consistent with the corresponding JCPDS card, with ZnNi2S4 at 36-0788. The ZnNi2S4 sample has five distinct diffraction peaks at 27.3°, 35.7°, 54°, 56.4°, and 63.8°, corresponding to five crystal planes (110), (101), (211), (220), and (310), respectively. The diffraction peaks of ZnNi2S4 exhibit dwarfing and broadening characteristics, indicating that the synthesized ZnNi2S4 has poor crystallinity and nanoscale size. The CFC@ZnNi2S4 sample exhibits two broad peaks at 25.4° and 43.2°, which is due to the presence of carbon cloth (CFC) in the sample, consistent with the XRD pattern of pure CFC. No diffraction peaks were detected in the XRD pattern for materials other than the carbon cloth substrate, indicating that the synthesized ZnNi2S4 has high purity.

[0086] The materials prepared by comparative examples 1 to 3 are relatively loose, irregular in shape, and unevenly distributed. They are easy to fall off during the cycle and have poor cycle performance.

[0087] The specific capacity test results of the carbon cloth-supported heterostructure material in Example 1 are shown in Table 1, and the cycling performance curve is shown in Figure 3. It can be found that the electrode CFC@ZnNi2S4 at 0.1 A·g -1 After 100 cycles at a current density, it still retains 2026.2 mAh·g. -1 It exhibits high discharge specific capacity and a capacity retention rate of 98.24%, demonstrating good specific capacity and capacity retention. Compared to single-metal sulfide salts NiS and ZnS, the bimetallic sulfide salt supported in this application is more conducive to improving cycle performance.

[0088] [Pouch Battery]

[0089] Assemble a pouch cell according to the materials and procedures of the CR2032 coin-shaped battery, and conduct overall electrochemical testing of the battery.

[0090] Figure 4 shows the structure of the CFC@ZnNi2S4‖Li foil soft-pack battery in Example 1, where CFC@ZnNi2S4 is used as the negative electrode and lithium foil / lithium sheet (Li foil) is used as the positive electrode.

[0091] The pouch cell in Example 1 operates at a current density of 0.5 A·g -1 The capacity retention rate after 100 cycles is shown in Table 1, and the cycle performance curve is shown in Figure 5. The cycle data shows that after 100 cycles, the pouch battery still retains 322.60 mAh / g. -1 The discharge specific capacity and capacity retention rate are 94.13%, indicating excellent cycle life and capacity retention, which can meet the needs of long-term use. Furthermore, the coulombic efficiency of the pouch cell is close to 100%, demonstrating its good reversibility.

[0092] Table 1

[0093] As can be seen from the above, compared with the comparative examples, in the embodiments of this application, the bimetallic sulfide salt is uniformly grown as tile-like nanosheets on the carbon fiber conductive network in carbon cloth. The nanosheets are interconnected and intersecting to form a three-dimensional network structure. The abundant empty spaces between the nanosheets can promote electrolyte penetration and lithiation of the electrode. The tile-like nanosheets also introduce more active sites, and the significant gaps between the nanosheets greatly increase the contact area between the material and the electrolyte, improving conductivity and providing more active sites for electrochemical reactions. The bimetallic sulfide salt can also combine the advantages of multi-component and multi-phase structures, generating sufficient boundaries and small crystal domains, which helps to achieve rapid kinetics that avoid solid-state diffusion and promote ion diffusion. The carbon cloth-supported heterostructure material of this application can significantly improve the rate performance, specific capacity, and cycle performance of the composite anode.

[0094] Furthermore, it can be seen that the overall effect is better when all process parameters are within the preferred range of this application.

[0095] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A carbon cloth-supported heterostructure material, characterized in that, Includes carbon cloth and a bimetallic sulfide salt supported on the surface of the carbon cloth, wherein, The carbon cloth has a carbon fiber conductive network, and the bimetallic sulfide salt is grown on the surface of the carbon fiber conductive network in the form of tiled nanosheets to form a three-dimensional network structure. The metal in the bimetallic sulfide salt includes zinc.

2. The carbon cloth-supported heterostructure material according to claim 1, characterized in that, The bimetallic sulfide salts include one or more of nickel zinc sulfide, iron zinc sulfide, cobalt zinc sulfide, and aluminum zinc sulfide.

3. The carbon cloth-supported heterostructure material according to claim 1 or 2, characterized in that, By weight percentage, the carbon cloth accounts for 85-88% of the carbon cloth-supported heterostructure material, and the bimetallic sulfide salt accounts for 12-15% of the carbon cloth-supported heterostructure material.

4. The carbon cloth-supported heterostructure material according to any one of claims 1 to 3, characterized in that, The maximum length of a single tile-like nanosheet is 2–6 μm; and / or In the carbon fiber conductive network, the diameter of the carbon fibers is 5 to 7 μm.

5. The method for preparing the carbon cloth-supported heterostructure material according to any one of claims 1 to 4, characterized in that, Includes the following steps: Step S1: Anneal the carbon cloth to obtain pretreated carbon cloth; Step S2: Mix zinc salt, second metal salt, urea, hexamethylenetetramine and water to obtain a metal solution; The pretreated carbon cloth is immersed in the metal solution to carry out a hydrothermal reaction to obtain the precursor; Step S3: Immerse the precursor in an aqueous solution of sulfide to carry out a sulfidation reaction to obtain the carbon cloth-supported heterostructure material.

6. The preparation method according to claim 5, characterized in that, In step S1 The annealing temperature is 350–450°C, and the time is 1.5–2.5 hours. Preferably, before the annealing, step S1 further includes the steps of cleaning and drying the carbon cloth in sequence: ultrasonically cleaning the carbon cloth with acetone for 50-70 minutes, then ultrasonically cleaning it with a mixture of ethanol and water for 50-70 minutes, and then drying it at 70-90°C until dry.

7. The preparation method according to claim 5 or 6, characterized in that, In step S2 The zinc salt comprises zinc nitrate hexahydrate, and the second metal salt comprises nickel chloride hexahydrate, iron chloride, cobalt chloride, or aluminum chloride; preferably, the weight ratio of the zinc salt to the second metal salt is 1:(2-3); and / or The weight ratio of urea to hexamethylenetetramine is 1:(0.25-0.5); preferably, the weight ratio of the zinc salt to urea is 1:(6-7); and / or The hydrothermal reaction is carried out at a temperature of 110–130°C for 5–7 hours. Preferably, step S2 further includes the following steps: washing the precursor with a mixture of ethanol and water for 50-70 minutes, and then drying it at 70-90°C until dry.

8. The preparation method according to any one of claims 5 to 7, characterized in that, In step S3 The sulfide includes one or more of sodium sulfide, sodium sulfide nonahydrate, and thiourea; preferably, the weight ratio of the sum of the zinc salt and the second metal salt to the weight of the sulfide is 1:(0.65-0.75); and / or The vulcanization reaction is carried out at a temperature of 150–170°C for 5–7 hours. Preferably, step S3 further includes the following steps: washing the carbon cloth-supported heterostructure material with a mixture of ethanol and water for 50-70 minutes, and then drying it at 70-90°C until dry.

9. A lithium-ion battery negative electrode, characterized in that, Includes the carbon cloth-supported heterostructure material according to any one of claims 1 to 4.

10. A lithium-ion battery, characterized in that, Includes the lithium-ion battery negative electrode as described in claim 9.

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