Preparation method and application of hierarchical structure CuS electrode material interpenetrated with conductive network structure

Abstract

This invention discloses a method for preparing a hierarchical CuS electrode material with an interpenetrating conductive network structure and its application. Copper chloride dihydrate and thioacetamide are dissolved in a mixed solvent of ethanol and water under ultrasonic conditions. The thioacetamide solution is then added dropwise to the copper chloride solution under ultrasonic conditions and reacted in a 60°C water bath. Hydrochloric acid, aniline, and ammonium persulfate are added to the resulting mixture, and the reaction continues in a 50-70°C water bath to form a polyaniline coating layer. After the reaction, the mixture is centrifuged, washed three times with deionized water and ethanol respectively, and then dried overnight in a 60°C oven to obtain a hierarchical CuS electrode material with an interpenetrating conductive network structure exhibiting excellent conductivity. When used as an AZIBs anode material, the hierarchical CuS electrode material prepared by this invention exhibits a faster electron transfer rate and Zn... 2+ The diffusion kinetics exhibit excellent rate performance and cycling stability.

Description

Technical Field

[0002] This invention belongs to the field of zinc-ion battery anode material preparation technology, specifically relating to a method for preparing a hierarchical CuS electrode material with an interpenetrating conductive network structure and its application. Background Technology

[0004] With the advancement of the "dual carbon" goal, the importance of clean energy sources, represented by wind and solar power, has become increasingly prominent. However, due to time and space constraints, direct grid connection is difficult, making the development of large-scale energy storage technologies strategically significant. Among various energy storage technologies, lithium-ion batteries are widely used due to their high energy density, but the scarcity of lithium resources, rising costs, and the flammability and toxicity of organic electrolytes limit their application in large-scale energy storage. In recent years, multivalent metal-ion batteries, represented by aqueous electrolytes, have made significant progress. Among them, aqueous zinc-ion batteries (AZIBs) have stood out due to their advantages such as low cost, high safety, and widespread zinc resource distribution. They use a neutral saline solution as the electrolyte, manganese / vanadium-based materials as the positive electrode, and zinc metal as the negative electrode. This avoids the flammability problem of organic batteries and overcomes the disadvantages of traditional energy storage batteries, such as high pollution, heavy weight, and high price, making them one of the key technologies for achieving energy transition and environmental sustainability. However, zinc metal negative electrodes suffer from adverse effects during battery cycling, such as zinc dendrite formation, corrosion, passivation, and hydrogen evolution reactions. These problems with zinc negative electrodes seriously hinder the practical application of aqueous zinc-ion batteries. Therefore, designing and exploring novel negative electrodes and improving the overall performance of aqueous zinc-ion batteries are key to realizing the practical application of aqueous zinc-ion batteries.

[0005] In the prior art, patent document CN201910056270.7 discloses a negative electrode material for rechargeable aqueous zinc-ion batteries, its preparation and application, wherein the chemical formula of the negative electrode material is M. xTiS2, where M is at least one of hydrogen, copper, alkali metals, and alkaline earth metals, is a modified titanium disulfide material obtained by modifying titanium disulfide with alkali metal or alkaline earth metal ions. This modified titanium disulfide material can be used as a negative electrode material in aqueous zinc-based batteries, exhibiting high capacity and long cycle life. Patent document CN202210453402.1 discloses a method for preparing a zinc-ion battery negative electrode and its active material, as well as a zinc-ion battery. The nano-vanadium tetrasulfide negative electrode active material provides a large number of active sites for zinc ion insertion and extraction, improving zinc ion migration kinetics and reducing zinc dendrite growth, thereby improving the cycle stability of the negative electrode material. Simultaneously, the nano-vanadium tetrasulfide negative electrode active material has a relatively low potential, resulting in a high degree of compatibility with the zinc ion positive electrode. The lower potential better maintains the structural stability of the material, further improving its cycle performance. Patent document CN202210904104.X discloses a molybdenum disulfide hierarchical double-layer hollow nanotube anode material for zinc-ion batteries. When the molybdenum disulfide hierarchical double-layer hollow nanotubes are combined with self-made ZnMn2O4 to assemble a "rocking chair" aqueous zinc-ion battery, they exhibit excellent electrochemical performance at 1Ag. -1 After 10,000 cycles, it exhibits a high capacity retention rate of 86.6%, effectively solving the battery quality problem caused by zinc dendrite formation. Patent document CN202311188241.9 discloses a carbon fiber-supported copper sulfide / copper telluride nanocomposite material, its preparation method, and its application in zinc-ion batteries. This carbon fiber-supported copper sulfide / copper telluride nanocomposite material comprises a flexible carbon fiber substrate with a copper sulfide / copper telluride heterojunction material loaded on the carbon fiber surface. As a negative electrode in zinc-ion batteries, the copper sulfide / copper telluride heterojunction can effectively buffer the volume change of the active material, synergistically enhancing the material's capacity performance, thereby improving zinc-ion storage performance and showing certain advantages in zinc-ion battery negative electrode material applications. Patent document CN202511741641.7 discloses a tellurium-doped copper sulfide-based nanocomposite material with a core-shell structure, its preparation method, and its applications. The inner layer of this nanocomposite material consists of microspheres formed by stacking tellurium-doped copper sulfide flower-like nanosheets; the outer coating layer is a carbon layer. The synergistic effect of tellurium doping and carbon coating effectively enhances the material's electronic conductivity and structural stability, significantly improving the cycle performance and rate performance of aqueous zinc-ion batteries. As a negative electrode for zinc-ion batteries, it effectively improves cycle reversibility, exhibits significant reversible capacity, and enhances zinc-ion battery performance, making it suitable for industrial production and large-scale energy storage. However, the technical solution in the aforementioned patent document does not involve any description of polyaniline-modified copper sulfide, nor does it provide any technical inspiration for establishing a continuous interfacial conductive network between the polyaniline and copper sulfide matrix through the construction of a conductive network to improve the overall electronic conductivity of the zinc-ion battery electrode and buffer volume changes during charge-discharge cycles.

[0006] Transition metal sulfides (ZnIs) have attracted widespread attention in the field of zinc-ion battery anode materials due to their high theoretical specific capacity, abundant redox active sites, and excellent ion transport properties. Among them, copper sulfide, with its abundant resources, environmental friendliness, mild preparation process, suitable redox potential, and excellent structural stability, is a highly promising anode material for zinc-ion batteries. However, copper sulfide materials have several shortcomings that urgently need to be addressed: First, its intrinsic semiconductor properties result in low conductivity, limiting charge transfer kinetics during charging and discharging, especially at high current densities where severe polarization makes rate performance difficult to guarantee; second, Zn... 2+ The insertion / extraction processes are accompanied by significant volume expansion and contraction, which can easily lead to particle pulverization and structural collapse, resulting in the loss of active materials. Thirdly, the polysulfides generated during the reaction are easily soluble in aqueous electrolytes, triggering a shuttle effect and causing continuous capacity decay during cycling. Therefore, it is urgent to find suitable and effective strategies to regulate copper sulfide to solve these problems.

[0007] Existing technology, patent document CN202111016179.6 discloses a polymer-modified anode material, its preparation method, and its application. The anode material includes titanium disulfide and a polymer embedded between the titanium disulfide layers. The polymer is polypyrrole, polyaniline, or polythiophene. The anode material is obtained by modifying the titanium disulfide layers using polymer embedding. When used in aqueous zinc-ion batteries, it not only avoids the zinc dendrite problem caused by using metallic zinc as the anode material, but also effectively improves the battery's specific capacity, cycle stability, and rate performance, thereby extending the battery's lifespan and expanding its applicability. The technical solution in this patent document modifies titanium disulfide with a layered structure. The purpose of this modification is to utilize an in-situ polymer embedding strategy to promote the growth of Zn in the TiS2 anode material. 2+ The embedding dynamics, and can store Zn for a long time. 2+ Therefore, using it as the negative electrode material for aqueous zinc-ion batteries can effectively improve the cycle stability and rate performance of aqueous zinc-ion batteries. The technical solution in this patent document does not involve any record of polyaniline-modified copper sulfide, nor does it involve any technical inspiration related to establishing a continuous interfacial conductive network between polyaniline and copper sulfide matrix by constructing a conductive network to improve the overall electronic conductivity of the electrode and buffer volume changes during charge-discharge cycles. Summary of the Invention

[0009] The technical problem solved by this invention is to provide a method for preparing a hierarchical CuS electrode material with interpenetrating conductive network structures. When used as an AZIBs anode material, the hierarchical CuS material prepared by this method can provide Zn...+ Storage provides a good conductive network structure and abundant active sites, thereby achieving high capacity and stability. The synthesis strategy established in this invention can provide guidance for the development of novel AZIBs anode materials with high performance, low cost, and high cycle stability.

[0010] This invention addresses the problems existing in current sulfide AZIBs anode materials by constructing a continuous interfacial conductive network between polyaniline and the copper sulfide matrix. This interfacial conductive network can improve the overall electronic conductivity of the electrode and buffer the volume changes of the electrode during charge-discharge cycles. The copper sulfide has a nanosheet self-assembled microflower structure with abundant porosity, which is conducive to buffering volume changes during cycling and rapid transport of zinc ions. This unique structural effect can ensure the structural stability and high specific capacity of the electrode during long-term cycling.

[0011] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a method for preparing a hierarchical CuS electrode material with an interpenetrating conductive network structure, the specific preparation steps of which are as follows:

[0012] Step S1: Copper chloride dihydrate and thioacetamide are dissolved in a mixed solvent of ethanol and water under ultrasonic conditions to prepare copper chloride solution and thioacetamide solution, respectively.

[0013] Step S2: Thioacetamide solution is added dropwise to copper chloride solution under ultrasonic conditions, and then reacted in a water bath at 60°C;

[0014] Step S3: Add hydrochloric acid, aniline, and ammonium persulfate to the mixed solution after the reaction in step S2, and continue the reaction under a water bath at 50~70℃ to form a polyaniline coating layer. After the reaction is completed, centrifuge, wash several times with deionized water and ethanol respectively, and then dry in an oven at 60℃ to obtain a hierarchical CuS electrode material with an interpenetrating conductive network structure that has excellent conductivity.

[0015] Furthermore, in step S1, the volume ratio of ethanol to water in the mixed solvent of ethanol and water is 1:3.

[0016] Furthermore, the reaction time in step S2 is 24~48h.

[0017] Furthermore, in step S3, hydrochloric acid, aniline, and ammonium persulfate are added, and the reaction continues for 12-24 hours.

[0018] Furthermore, in step S3, the thickness of the polyaniline coating layer is 2~20 nm.

[0019] The application of the hierarchical CuS electrode material with interpenetrating conductive network structure described in this invention in the preparation of zinc-ion battery anode materials.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects: the preparation process of the present invention is simple and the reaction conditions are mild. The in-situ polymerization of CuS core and polyaniline shell is achieved by a two-step method using a low temperature water bath. No high temperature and high pressure equipment is required. The reaction process is easy to control and has good repeatability, making it suitable for large-scale production.

[0021] The polyaniline / CuS prepared in this invention exhibits superior electrochemical performance in aqueous zinc-ion battery anode systems compared to pure CuS materials. Its core advantage stems from the systematic reinforcement of the intrinsic shortcomings of the material by the polyaniline coating layer: pure CuS, as a semiconductor material, has low intrinsic conductivity and high charge transfer impedance during charging and discharging, and its properties are significantly improved by the presence of Zn... 2+ The significant volume changes during insertion / extraction can easily lead to particle pulverization, structural collapse, and polysulfide dissolution and loss. Polyaniline, as a highly conductive polymer, can not only construct a continuous electron transport network between the CuS surface and the framework, significantly reducing the overall electrode impedance and optimizing charge transfer kinetics, but its flexible shell can also effectively buffer volume expansion, suppress the dissolution and shuttle effect of active materials, and maintain the integrity of the electrode structure. Simultaneously, the hydrophilicity of polyaniline can improve electrolyte wettability and reduce Zn content. 2+ The diffusion resistance is reduced and interfacial side reactions are minimized. Furthermore, additional zinc-storing active sites are provided, creating a synergistic effect with CuS. Ultimately, this results in the polyaniline / CuS composite electrode material exhibiting superior overall performance in terms of specific capacity, rate capability, and long-cycle stability. The prepared hierarchical CuS electrode material with interpenetrating conductive network structure exhibits an initial discharge capacity of approximately 573.5 mA hg at a current density of 0.2 A / g. -1 After 110 cycles, the specific capacity can still be maintained at 305.7 mA hg. -1 Compared with existing sulfide materials, its performance is superior (see Table 1). Attached Figure Description

[0023] Figure 1 This is a field emission scanning electron microscope image of the polyaniline / CuS composite material from Example 1.

[0024] Figure 2 This is a graph showing the cycling performance of the polyaniline / CuS composite material prepared in Example 1 at a current density of 0.2 A / g.

[0025] Figure 3 This is a field emission scanning electron microscope image of the CuS material prepared in Comparative Example 1.

[0026] Figure 4 This is a graph showing the cycling performance of the CuS material prepared in Comparative Example 1 at a current density of 0.2 A / g.

[0027] Figure 5The X-ray diffraction patterns are those of the polyaniline / CuS composite material and CuS material prepared in Example 1 and Comparative Example 1. Detailed Implementation

[0029] The following examples further illustrate the above-described content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention.

[0030] Example 1

[0031] Step S1: Dissolve 0.5400g of copper chloride dihydrate and 0.2700g of thioacetamide in a mixed solvent of ethanol and water (volume ratio of 1:3) under ultrasonic conditions to obtain copper chloride solution and thioacetamide solution, respectively.

[0032] Step S2: Thioacetamide solution is added dropwise to copper chloride solution under ultrasonic conditions, and then reacted in a water bath at 60°C for 24 hours;

[0033] Step S3: Add 40 mL of 1 M hydrochloric acid solution, 520 μL of aniline, and 0.4800 g of ammonium persulfate to the mixed solution after the reaction in step S2, and continue the reaction under water bath conditions of 50~70℃ to form a polyaniline coating layer. After the reaction is completed, centrifuge, wash three times with deionized water and ethanol respectively, and then dry in an oven at 60℃ overnight to obtain a hierarchical CuS electrode material with an interpenetrating conductive network structure (CuS@PANI) with excellent conductivity.

[0034] The electrochemical testing method for the hierarchical CuS electrode material with interpenetrating conductive network structure is as follows:

[0035] The electrochemical performance of the negative electrode material was studied using coin cells. DMF was used as the solvent for the negative electrode. The negative electrode was formulated into a slurry with a mass ratio of CuS@PANI:Supper P:PVDF = 7:2:1. The slurry was then uniformly coated onto copper foil and dried in a vacuum drying oven at 110℃ for 12 hours. After die-cutting, the negative electrode for the experimental battery was obtained. Zinc foil was used as the counter electrode, a 2.0M ZnSO4 aqueous solution was used as the electrolyte, and a Watman GF / A glass fiber separator was used. Coin cells were assembled in air. Charge-discharge cycle tests were performed on the coin cells. The charge-discharge cutoff voltage was 0.2~1V, and the charge-discharge current was 0.2A / g.

[0036] Figure 1 Field emission scanning electron microscope (FESEM) image of polyaniline / CuS composite material, from Figure 1It can be seen that the polyaniline / CuS composite electrode material exhibits an overall aggregated blocky / granular morphology, microscopically composed of stacked nanoscale particles. The flower-like structure of the original CuS is no longer obvious, which is the result of the polyaniline coating layer modifying the precursor morphology. The material particles are relatively uniformly distributed, with no obvious large-size agglomerates; the particle size is approximately several hundred nanometers to 1 μm. The rough coating layer on the surface confirms the successful coating of polyaniline on the CuS surface. Figure 2 The cycling performance graph shows that the specific capacity is approximately 573.5 mAh g at a current density of 0.2 A / g. -1 When the prepared CuS electrode material with an interpenetrating conductive network structure is used as an AZIBs anode material, its specific capacity can still be maintained at 305.7 mA hg after 110 cycles at a current density of 0.2 A / g. -1 .

[0037] Comparative Example 1

[0038] Step S1: Dissolve 0.5400g of copper chloride dihydrate and 0.2700g of thioacetamide in a mixed solvent of ethanol and water (volume ratio of 1:3) under ultrasonic conditions to obtain copper chloride solution and thioacetamide solution, respectively.

[0039] Step S2: Thioacetamide solution was added dropwise to copper chloride solution under ultrasonic conditions, and then reacted in a 60°C water bath for 24 hours. After centrifugation at 8000 rpm, the mixture was washed three times with deionized water and ethanol, and then dried overnight in a 60°C oven to obtain pure CuS electrode material.

[0040] The electrochemical testing methods for the obtained CuS electrode material are as follows:

[0041] The electrochemical performance of the negative electrode material was studied using coin cells. DMF was used as the solvent for the negative electrode. The negative electrode was formulated into a slurry with a mass ratio of CuS:Supply P:PVDF = 7:2:1. The slurry was then uniformly coated onto copper foil and dried in a vacuum drying oven at 110℃ for 12 hours. After die-cutting, the negative electrode for the experimental battery was obtained. Zinc foil was used as the counter electrode, a 2.0M ZnSO4 aqueous solution was used as the electrolyte, and a Watman GF / A glass fiber separator was used. Coin cells were assembled in air. Charge-discharge cycle tests were performed on the coin cells. The charge-discharge cutoff voltage was 0.2~1V, and the charge-discharge current was 200mA / g.

[0042] from Figure 3 As can be seen from a and b, CuS consists of a micro-flower-like structure composed of nanosheets, with an average particle size of approximately 500 nm. From the perspective of cycle performance... Figure 4 It can be seen that when the current density is 0.2 A / g, the specific capacity is approximately 373.5 mA hg. -1When the prepared micro-flower-like CuS material is used as an anode material for AZIBs, its specific capacity can still be maintained at 209.59 mA hg after 110 cycles at a current density of 0.2 A / g. -1 .

[0043] Table 1. Comparison of electrochemical performance of zinc-ion batteries prepared with negative electrode materials of this patent and those reported in other literature.

[0044] <![CDATA[Mo6S8]]> Nanocubes <![CDATA[0.6A g -1 After 350 cycles, the specific capacity is 60.0 mA hg. -1 Capacity retention rate: 85.0% [1] <![CDATA[TiSe2]]> Nanosheets <![CDATA[0.8A g -1 After 300 cycles, the specific capacity is 50.0 mA hg. -1 Capacity retention rate: 70.0% [2] PTCDI Nanosheets <![CDATA[3A g -1 After 1500 cycles, the specific capacity is 130.0 mA hg. -1 Capacity retention rate: 96.0% [3] CuS@PANI Nanocrystalline assemblies <![CDATA[0.2A g -1 After 150 cycles, the specific capacity is 290.5 mA hg. -1 Capacity retention rate: 98.0% This job

[0045] [1]Yingwen C , Langli L , Li Z , et al.Highly Reversible Zinc-IonIntercalation into Chevrel Phase Mo6S8 Nanocubes and Applications for Advanced Zinc-Ion Batteries.[J].ACS applied materials & interfaces, 2016,8(22):13673-7.

[0046] [2]Li W, Yanan W, Siliang W, et al. A novel TiSe2 (de)intercalationtype anode for aqueous zinc-based energy storage[J]. Nano Energy, 2022,93:106896.

[0047] [3] Nannan L ,

[0048] The above embodiments describe the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the scope of the principles of the present invention, and all such changes and modifications fall within the protection scope of the present invention.

Claims

1. A method for preparing a hierarchical CuS electrode material with interpenetrating conductive network structure, characterized in that The specific preparation steps are as follows: Step S1: Copper chloride dihydrate and thioacetamide are dissolved in a mixed solvent of ethanol and water under ultrasonic conditions to prepare copper chloride solution and thioacetamide solution, respectively. Step S2: Thioacetamide solution is added dropwise to copper chloride solution under ultrasonic conditions, and then reacted in a water bath at 60°C; Step S3: Add hydrochloric acid, aniline and ammonium persulfate to the mixed solution after the reaction in step S2 and continue the reaction under a water bath at 50~70℃ to form a polyaniline coating layer. After the reaction is completed, centrifuge, wash with deionized water and ethanol several times, and then dry in an oven at 60℃ to obtain a hierarchical CuS electrode material with an interpenetrating conductive network structure that has excellent conductivity. In the CuS electrode material, a continuous interfacial conductive network is established between polyaniline and the copper sulfide matrix by constructing a conductive network. This interfacial conductive network can improve the overall electronic conductivity of the electrode and buffer the volume change of the electrode during charge-discharge cycles. The copper sulfide has a nanosheet self-assembled microflower structure with abundant pores, which is conducive to buffering the volume change during cycling and the rapid transport of zinc ions. This unique structural effect can ensure the structural stability and high specific capacity of the electrode during long-term cycling.

2. The method of claim 1, wherein the method further comprises: In step S1, the volume ratio of ethanol to water in the mixed solvent of ethanol and water is 1:

3.

3. The method of claim 1, wherein the method further comprises: The reaction time in step S2 is 24~48h.

4. The method of claim 1, wherein the method further comprises: In step S3, hydrochloric acid, aniline, and ammonium persulfate are added, and the reaction continues for 12-24 hours.

5. The method of claim 1, wherein the method further comprises: In step S3, the thickness of the polyaniline coating layer is 2-20 nm. As a highly conductive polymer, polyaniline not only constructs a continuous electron transport network between the CuS surface and the framework, significantly reducing the overall electrode impedance and optimizing charge transfer kinetics, but its flexible shell also effectively buffers volume expansion, suppresses the dissolution and shuttle effect of active materials, and maintains the integrity of the electrode structure. Simultaneously, the hydrophilicity of polyaniline improves electrolyte wettability and reduces Zn content. 2+ It reduces diffusion resistance and interfacial side reactions, and also provides additional zinc storage active sites, forming a synergistic effect with CuS. Ultimately, the polyaniline / CuS composite electrode material exhibits superior overall performance in terms of specific capacity, rate performance, and long-cycle stability.

6. The application of the hierarchical CuS electrode material with interpenetrating conductive network structure prepared by the method according to any one of claims 1 to 5 in the preparation of zinc-ion battery anode materials.

7. Use according to claim 6, characterized in that The specific process is as follows: DMF is used as the solvent for the negative electrode. The negative electrode sheet is formulated into a slurry according to the mass ratio of CuS@PANI:Supper P:PVDF=7:2:

1. The slurry is then uniformly coated onto copper foil and dried in a vacuum drying oven at 110℃ for 12 hours. After stamping, the negative electrode sheet is obtained. Zinc foil is used as the counter electrode. The electrolyte is a 2.0M ZnSO4 aqueous solution, and the separator is a Watman GF / A glass fiber separator. The coin cell is assembled in an air atmosphere. The initial discharge capacity of the coin cell is 573.5 mA hg at a current density of 0.2 A / g. -1 After 110 cycles, the specific capacity can still be maintained at 305.7 mA hg. -1 .

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