Amorphous cobalt sulfide nanosheet arrays, their preparation and applications

Abstract

This invention belongs to the field of electrode materials, specifically disclosing a method for preparing amorphous cobalt sulfide nanosheet arrays. The method involves obtaining a precursor of amorphous cobalt sulfide loaded on a support, followed by immersion in deoxygenated water to undergo a morphology transformation, converting the irregular morphology of the loaded amorphous cobalt sulfide into a nanosheet array morphology. This invention provides a novel approach and method for water-induced morphology transformation of cobalt sulfide. It innovatively immerses amorphous cobalt sulfide in deoxygenated water, allowing for morphology transformation under the induction of water molecules. This transforms the irregular morphology of the amorphous cobalt sulfide into a regular nanosheet array morphology, exposing more reactive sites, shortening ion diffusion distance, and effectively inhibiting the aggregation of amorphous cobalt sulfide. The process described in this invention can yield materials with high specific surface area and excellent electrochemical performance.

Description

Technical Field

[0001] This invention belongs to the field of functional electrode materials for energy storage and conversion, specifically relating to the preparation, modification method and application of an amorphous cobalt sulfide material with a high specific surface area nanosheet array morphology. Background Technology

[0002] (1) Alkaline water electrolysis for hydrogen production: Alkaline water electrolysis for hydrogen production has advantages such as wide availability of raw materials, simple equipment, and high hydrogen purity. Compared with traditional hydrogen production technologies such as water-gas method and petroleum gas reforming, it is more green, environmentally friendly, and sustainable, and is considered a feasible direction for large-scale industrial hydrogen production in the future. It can play an important role in the field of new energy storage and conversion. However, in an alkaline environment, the hydrogen evolution reaction (HER) needs to overcome an additional water splitting energy barrier, resulting in a slower kinetics compared to an acidic environment. At present, alkaline water electrolysis for hydrogen production still heavily relies on Pt-based catalysts, which are costly and their stability under high current is still difficult to meet the requirements of large-scale hydrogen production. Therefore, it is not advantageous among various hydrogen production technologies and is difficult to promote and apply. Research in recent decades has found that compounds of metals such as W, Mo, Co, and Ni, such as nitrides, sulfides, phosphides, and carbides, theoretically have hydrogen evolution catalytic performance comparable to Pt-based catalysts. They are expected to replace Pt-based catalysts, greatly reduce the cost of water electrolysis for hydrogen production, and realize large-scale application.

[0003] Amorphous Co x The structure of S (cobalt sulfide) and amorphous Mo x Similar to S, which is composed of small clusters, the Co metal center is surrounded by S atoms and is not preferentially exposed to the electrolyte. This means that S atoms are preferentially exposed to the electrolyte and become catalytically active sites, increasing the size of amorphous Co. x The specific surface area of ​​S facilitates further exposure of catalytic active sites, improving material utilization. Furthermore, Co... x S has near-metallic conductivity and theoretically possesses higher hydrogen evolution catalytic activity. However, amorphous Co... x The S site of S makes it difficult to balance the three steps of HER in alkaline water electrolysis, leading to difficulties in water molecule adsorption-dissociation in an alkaline environment. * The adsorption-desorption imbalance at the active site and the irregular morphology of amorphous Co x S readily aggregates spontaneously during the reaction, and these factors combined mean that its HER catalytic activity and stability still cannot compare with Pt-based catalysts. How to effectively expose amorphous Co... x The S atom catalytic site of S, regulating the adsorption and cleavage behavior of H2O at the active site, and H * Adsorption and desorption behavior at active sites, while inhibiting amorphous Co xThe spontaneous aggregation of S is to enhance the amorphous Co x The key to the hydrogen evolution catalytic activity and stability of S materials.

[0004] Currently, amorphous Co x The preparation of S materials mainly involves low-temperature calcination of precursors or hydrothermal-solvothermal methods. These methods suffer from drawbacks such as cumbersome processes, high energy consumption, long processing times, and incomplete reactions, making rapid, large-scale production difficult. Furthermore, to further improve the catalytic performance, modification is generally required. A common approach is to uniformly introduce heterogeneous elements into the precursor, often through calcination or secondary calcination to introduce other elements. This process is difficult to control and hinders the effective exposure of active sites. Therefore, a simple method for synthesizing amorphous Co is needed. x S precursor materials are used, and then the specific surface area of ​​the material is increased through simple surface modification or surface reconstruction to fully expose active sites or regulate the electronic structure of active sites, thereby significantly improving the HER catalytic activity of the catalyst. In addition, the regular three-dimensional nanosheet array morphology can effectively suppress amorphous Co x Aggregation of S in the HER process to improve catalyst stability is currently a key focus in the development of this type of catalyst.

[0005] (2) Lithium / sodium ion battery energy storage: Co x S-materials are common metal sulfides, and their lithium / sodium storage mechanism is as follows: (M = Li, Na), with a theoretical capacity close to 600 mAh g in lithium / sodium ion battery applications. -1 Co nanosheets self-assembled into flower-like morphology x Compared with other metal sulfide morphologies, S can effectively increase the contact area with the electrolyte and increase M. + The insertion-extraction sites improve charge-discharge capacity and shorten M. + The diffusion distance, and the flower-like morphology can effectively suppress amorphous Co x The aggregation of S exhibits better and more stable electrochemical performance. Compared with traditional hydrothermal methods, chemical vapor deposition, and solid-state reaction methods, electrodeposition overcomes the disadvantages of these methods, such as high energy consumption, long time consumption, expensive equipment, and difficulty in large-scale synthesis, making it an ideal research direction for preparing more regular morphologies and better performance.

[0006] Electrodeposition can directly deposit active materials Co x S grows directly on the carrier surface without the need for binders, promoting M + (M = Li, Na) in Co x The diffusion process on the S surface enhances adhesion to the carrier, which is beneficial for improving the rate performance and utilization efficiency of the active material. How to optimize the electrodeposition process to prepare amorphous Co... xS, and through some simple methods, amorphous Co x The irregular morphology of S transforms into a relatively dense nanosheet array morphology to increase the contact area between the material and the electrolyte and shorten the M-phase flow. + The diffusion distance of (M = Li, Na) is to increase the diffusion distance of Co. x The key to the theoretical capacity and rate performance of S materials. Summary of the Invention

[0007] To address the issues of limited methods for preparing amorphous cobalt sulfide nanosheet arrays and the need to improve the specific surface area and electrochemical performance of the resulting materials, the primary objective of this invention is to provide a deoxygenated water-induced morphology transformation approach for preparing amorphous cobalt sulfide nanosheet arrays, aiming to obtain amorphous cobalt sulfide nanosheet arrays with high specific surface area, high electrochemical activity, and high stability.

[0008] The second objective of this invention is to provide an amorphous cobalt sulfide nanosheet array prepared by the aforementioned method and its application in catalytic electrodes and electrochemical devices.

[0009] A method for preparing an amorphous cobalt sulfide nanosheet array involves obtaining a precursor loaded with amorphous cobalt sulfide on a support, and then placing it in deoxygenated water to undergo morphological transformation, thereby transforming the irregular morphology of the loaded amorphous cobalt sulfide into a nanosheet array morphology.

[0010] This invention provides a novel approach and method for the spontaneous morphological transformation of cobalt sulfides. It innovatively involves immersing amorphous and irregularly shaped cobalt sulfides in deoxygenated water, whereby a morphological transformation occurs under the induction of water molecules. This transforms the irregular morphology of the amorphous cobalt sulfides into a nanosheet array morphology, exposing more active sites. The process described in this invention can yield materials with high specific surface area and excellent electrochemical performance.

[0011] In this invention, the precursor can be a conventional supported amorphous cobalt sulfide.

[0012] In the precursor described in this invention, the carrier is a three-dimensional carrier;

[0013] Preferably, the three-dimensional carrier is at least one of nickel foam, cobalt foam, and copper foam.

[0014] The research surface of this invention shows that by using a three-dimensional carrier and combining it with the deoxygenated water-induced morphology transformation process of amorphous cobalt sulfides described in this invention, synergistic effects can be achieved, which helps to further improve the electrochemical performance of the prepared materials.

[0015] In this invention, the pore density of the three-dimensional carrier is 60–120 PPI.

[0016] In this invention, the precursor can be prepared using known methods. For example, the precursor can be obtained by electrodepositing a support in a deposition solution containing a cobalt source and a sulfur source.

[0017] In this invention, the cobalt source is Co. 2+ The water-soluble salt can further be at least one of cobalt sulfate, cobalt chloride, and cobalt acetate;

[0018] In this invention, the sulfur source is a water-soluble thiosulfate, and may further be at least one of sodium thiosulfate, potassium thiosulfate, and ammonium thiosulfate.

[0019] In this invention, the molar ratio of cobalt source to sulfur source is 0.1 to 2:1, and more preferably 0.5 to 1.0:1;

[0020] In this invention, a pH adjuster may be added to the sedimentation solution, wherein the pH adjuster is at least one of dilute HCl and dilute H2SO4;

[0021] In this invention, the pH of the sedimentation solution is 3–5.5;

[0022] In this invention, the carrier is pretreated with dilute hydrochloric acid, acetone, anhydrous ethanol, and deionized water;

[0023] In this invention, the potential during the electrodeposition stage is -0.4 to -0.6 V vs. Ag / AgCl, and the solution is filled with saturated KCl solution;

[0024] In this invention, the loading of the amorphous cobalt sulfide in the precursor is 0.7–5.0 mg / cm³. -2 .

[0025] The present invention demonstrates that, under the aforementioned deoxygenated water-induced morphology transformation approach, further control of the loading amount of amorphous cobalt sulfide can further synergistically regulate the dissolution-precipitation behavior during the morphology transformation process, which helps to further improve the morphology, specific surface area, and electrochemical performance of the array.

[0026] In this invention, the precursor is pre-washed with water before the morphology transformation treatment.

[0027] In this invention, the deoxygenated water refers to water that has undergone pre-deoxygenation treatment. Research in this invention shows that using deoxygenated water causes amorphous cobalt sulfides to spontaneously dissolve and precipitate, undergoing morphological transformation under the induction of water molecules. Furthermore, it reduces the deterioration of the chemical properties of cobalt sulfides, thus improving electrochemical performance while achieving a high specific surface area.

[0028] In this invention, the deoxygenated water is ultrapure water, deionized water, tap water, drinking water, or other water with fewer impurities that has undergone deoxygenation treatment.

[0029] In this method, the dissolved oxygen content in the deoxygenated water is less than or equal to 1 ppm.

[0030] In this invention, the deoxygenated water can be obtained using known methods, for example, it can be water that has undergone boiling and / or bubbling treatment. The atmosphere bubbled in during the bubbling treatment is at least one inert gas such as nitrogen.

[0031] This invention also shows that further regulation of the amount of deoxygenated water added, temperature, and time during the deoxygenated water-induced morphology transformation process can promote the morphology transformation of the nanosheet array, which helps to further improve the specific surface area and electrochemical performance of the material.

[0032] In this invention, the liquid-to-solid ratio of the precursor and deoxygenated water is above 50 ml / g, and considering the processing cost, it can be further controlled at 50-200 ml / g.

[0033] In this invention, the temperature during the morphological transformation stage is above 0°C, preferably 20–100°C, more preferably 30–95°C, even more preferably 50–95°C, and still more preferably 60–90°C. Research in this invention shows that at the preferred morphological transformation temperature, the rate of morphological transformation is improved. Furthermore, it facilitates the subsequent Pt introduction modification process, thereby further improving the properties of the amorphous cobalt sulfide material.

[0034] In this invention, the morphological transformation time can be adjusted as needed. For example, when the morphological transformation temperature is high, the processing time can be appropriately shortened to consider processing efficiency; when the processing temperature is low, the processing time can be appropriately extended. In this invention, the morphological transformation processing time is more than 1 hour, preferably 2 to 100 hours. Preferably, when the morphological transformation temperature is between 50 and 95°C, the morphological transformation time is preferably 1.5 to 8 hours to consider processing efficiency. When the morphological transformation stage is carried out below 50°C, the morphological transformation time can be extended to more than 10 hours, and more preferably 50 to 100 hours.

[0035] As part of the same inventive concept, this invention also provides a method for introducing Pt, the implementation of which is as follows: A: The precursor is subjected to a Pt-introduction modification process in a deoxygenated aqueous solution containing a Pt source to obtain Pt-introduced amorphous cobalt sulfide; or, B: After morphology transformation treatment in deoxygenated water for more than 1 hour, a Pt source is added to the morphology transformation system for Pt-introduction modification treatment to obtain a Pt-introduced amorphous cobalt sulfide nanosheet array; or, C: After morphology transformation treatment induced by deoxygenated water, the nanosheet is then immersed in a deoxygenated aqueous solution containing a Pt source for treatment to obtain a Pt-introduced amorphous cobalt sulfide nanosheet array.

[0036] This invention demonstrates that by employing preferred methods B and C, the etching degree of the amorphous cobalt sulfide nanosheet array structure during the Pt introduction modification process can be reduced, further regulating the adsorption-dissociation behavior of H2O and H2O. * The adsorption and desorption behavior at active sites can be used to further improve material performance, such as the HER catalytic performance of alkaline water electrolysis.

[0037] In this invention, the Pt source is a water-soluble salt of Pt, and may further be at least one of PtCl4 and H2PtCl6;

[0038] Preferably, the mass ratio of Pt in the Pt source to the amorphous cobalt sulfide nanosheets in the precursor is 0.01 to 0.2:1, and more preferably 0.02 to 0.12:1.

[0039] The present invention also provides an amorphous cobalt sulfide nanosheet array prepared by the preparation method described above, which includes a carrier and an amorphous cobalt sulfide nanosheet array loaded on its surface;

[0040] Preferably, the specific surface area of ​​the amorphous cobalt sulfide nanosheet array is 67.5–104.2 m². 2 g -1 .

[0041] This invention also includes the application of the aforementioned amorphous cobalt sulfide nanosheet array as a HER catalytic material or electrode active material (negative electrode active material). In this invention, the negative electrode active material can be, for example, a negative electrode active material for an alkali metal ion battery, such as a lithium-ion battery or a sodium-ion battery.

[0042] The present invention also provides an electrode material comprising the amorphous cobalt sulfide nanosheet array described in the present invention;

[0043] Preferably, the electrode material is a HER catalytic electrode or the negative electrode of an alkali metal ion battery.

[0044] The present invention also provides an electrochemical device comprising the aforementioned array of amorphous cobalt sulfide nanosheets.

[0045] The electrode material and electrochemical device described in this invention, except for the amorphous cobalt sulfide nanosheet array described in this invention, can have other conventional components and structures.

[0046] Compared with the prior art, the advantages of the present invention are as follows:

[0047] (1) This invention provides a method for morphological transformation of amorphous cobalt sulfides induced by deoxygenated water.

[0048] The method for preparing modified Co in this invention involves a simple deoxygenated water-induced morphology transformation process, transforming amorphous Co with small specific surface area and irregular morphology into a modified Co. x S material is transformed into Co with high specific area and nanosheet array morphology. x S material, improved amorphous Co x The specific surface area of ​​the S material is large enough to fully expose the active sites and effectively inhibit the growth of amorphous Co. x The reunion of S. Compared to the irregular morphology of Co. x S material, Co nanosheet array morphology x The alkaline water electrolysis HER catalytic activity, lithium / sodium ion battery anode electrochemical performance, and stability of S material were significantly improved. This method fully utilizes the advantages of electrodeposition technology—green, environmentally friendly, efficient, and capable of large-scale preparation—and further enhances the morphology transformation of amorphous Co through a simple deoxygenated water-induced morphology transformation process. x S has a high specific surface area and stability, and the modification method is simple and easy to operate, which can meet the requirements of different process flows.

[0049] (2) Based on the innovative deoxygenated water-induced morphology transformation described in this invention, further combined control of parameters such as the loading amount of amorphous cobalt sulfide, transformation temperature, time, and molar concentration of Pt source can help to further improve the morphology transformation effect and array morphology, and help to further improve the electrochemical performance of the treated material.

[0050] (3) In the field of alkaline water electrolysis for hydrogen production, the Pt-modified Co with a high specific surface area nanosheet array morphology obtained by the preparation-modification method of this invention is used. x S-materials hold promise as a replacement for traditional commercially available precious metal Pt-based catalysts in water electrolysis cathodes, and are compatible with unmodified amorphous Co. x Compared to S materials, Co materials with high specific surface area nanosheet arrays modified by a small amount of Pt doping have different morphologies. x The S material exhibits a significant improvement in the catalytic activity of alkaline water electrolysis for hydrogen evolution, at a hydrogen evolution current density of 10 mA / cm². -2 The overpotential can be reduced to below 51mV, exhibiting catalytic performance close to that of commercial 20wt% Pt / C catalysts.

[0051] (4) In the field of lithium-ion battery energy storage, amorphous Co with irregular morphology and small specific surface area is preferred. x Co, with a high specific surface area nanosheet self-assembled into a flower-like morphology after further morphological transformation induced by deoxygenated water. x Compared with materials of other morphologies, S can effectively increase the contact area with the electrolyte, shorten the diffusion distance of lithium / sodium ions, and effectively suppress amorphous Co. x The aggregation of S exhibits better electrochemical performance and stability. This flower-like morphology of Co...x When S material is used as a negative electrode material for lithium-ion batteries, at 1.0 Ag... -1 At current density, the initial discharge specific capacity and charge specific capacity reach as high as 1910 mAh g. -1 and 1420mAh g -1 The coulombic efficiency is 74.34%, and its discharge specific capacity is still 1350 mAh g after 100 cycles. -1 The lithium storage performance mentioned above is superior to most reported carbon-free composite cobalt sulfide anode materials, and it also has good structural stability, giving it a significant competitive advantage among lithium-ion battery anode materials.

[0052] (5) In the field of sodium-ion battery energy storage, amorphous Co with irregular morphology and small specific surface area is preferred. x Co, with a high specific surface area nanosheet self-assembled into a flower-like morphology after further morphological transformation induced by deoxygenated water. x When S material is used as the anode material for sodium-ion batteries, at 0.2 A g -1 At current density, the initial discharge specific capacity and charge specific capacity are approximately 810 and 654 mAh g, respectively. -1 The corresponding initial coulombic efficiency is 80.7%. At a discharge current density of 1 A g... -1 At times, it can reach nearly 600mAh g -1 The discharge capacity is stable for 300 cycles, exhibiting good cycle stability. It also shows significantly better rate performance than materials without morphological transformation. The sodium storage performance is superior to most reported carbon-free composite cobalt sulfide anode materials, while also exhibiting good structural stability, giving it a clear competitive advantage among sodium-ion battery anode materials. Attached Figure Description

[0053] Figure 1 Example 1: Amorphous Co x XRD pattern and Raman pattern of S;

[0054] Figure 2 Example 1: Amorphous Co loaded on different carriers x SEM images of the morphological transformation induced by deoxygenated water at 30℃ before and after 48 h.

[0055] Figure 3 Example 2: Amorphous Co x SEM images of water-induced morphological transformation in water (with or without dissolved oxygen removal) at 30℃ before and after 48 hours of treatment.

[0056] Figure 4 Example 3: Amorphous Co x SEM images of S before and after morphological transformation induced by deoxygenated water at different temperatures and times;

[0057] Figure 5 Amorphous Co with different deposition charges in Example 4 x SEM images of morphological transformation induced by deoxygenated water at 30℃ before and after 48 hours;

[0058] Figure 6 Example 5: Depositing a certain amount of amorphous Co on copper foam. x SEM image of morphological transformation induced by deoxygenated water at 30℃ for 96 h;

[0059] Figure 7 Example 6: Amorphous Co x S. SEM image after Pt modification treatment for 4 h in deoxygenated aqueous solution containing 0.1 mM PtCl4 at 60℃.

[0060] Figure 8 Example 7: Amorphous Co x S was first treated with deoxygenated water to induce morphological transformation, and then modified with Pt. SEM image of the result.

[0061] Figure 9 The results of the HER catalytic performance test for alkaline water electrolysis in Example 8 (using nickel foam, i.e., NF, as a carrier);

[0062] Figure 10 The results of the HER catalytic performance test for alkaline water electrolysis in Example 8 (using nickel sheets, i.e., NP, as the support);

[0063] Figure 11 The results of the HER catalytic performance test for alkaline water electrolysis in Example 9 are as follows;

[0064] Figure 12 The results of the HER catalytic performance test for alkaline water electrolysis in Example 10 are as follows;

[0065] Figure 13 The results of the HER catalytic performance test for alkaline water electrolysis in Example 11 are as follows;

[0066] Figure 14 The results of the HER catalytic performance test for alkaline water electrolysis in Example 12 are as follows;

[0067] Figure 15 The results of the HER catalytic performance test for alkaline water electrolysis in Example 13 are as follows;

[0068] Figure 16 The results of the HER catalytic performance test for alkaline water electrolysis in Example 14 are shown.

[0069] Figure 17 Example 15a-Co x S&Wa-Co xComparison chart of long-cycle performance of S-96h used as a lithium-ion battery electrode, with a current density of 0.2Ag. -1 The cycle repeats 100 times.

[0070] Figure 18 Example 15W-a-Co x S-96h is used for long-cycle performance of lithium-ion battery electrodes, with a current density of 1Ag. -1 The cycle repeats 600 times.

[0071] Figure 19 Example 16a-Co x S&Wa-Co x Comparison chart of long-cycle performance of S-96h as an electrode for sodium-ion batteries, with a current density of 1Ag. -1 The cycle repeats 300 times.

[0072] Figure 20 Example 16a-Co x S&Wa-Co x Comparison of long-cycle performance of S-96h as a sodium-ion battery electrode, with a current density of 0.2Ag. -1 The cycle repeats 100 times.

[0073] Figure 21 Example 16a-Co x S&Wa-Co x Comparison of rate performance of S-96h as a sodium-ion battery electrode at different current densities; Detailed Implementation

[0074] The present invention will be further described in detail below with reference to specific embodiments.

[0075] This invention provides an amorphous cobalt sulfide (Co x The method for preparing S) nanosheet arrays involves obtaining a precursor loaded with amorphous cobalt sulfide on a support, and then placing it in deoxygenated water for morphology transformation treatment, so that the irregular morphology of the loaded amorphous cobalt sulfide is transformed into a regular nanosheet array morphology.

[0076] The design concept of the above technical solution lies in amorphous Co x S undergoes a morphological transformation induced by deoxygenated water, changing from a random morphology to a nanosheet array morphology to expose more active sites. After the deoxygenated water-induced morphological transformation process is completed, a certain volume of high-concentration Pt is injected into the morphological transformation system. 4+ By controlling the reaction time in a solution, Co in nanosheet array morphology can be achieved. x A small amount of Pt is introduced into the S surface to further modulate the amorphous Co. xThe electronic structure of the active sites on the S surface can be used to regulate the adsorption-dissociation behavior of H2O and H2O. * The adsorption and desorption behaviors at the active sites jointly contribute to improving the catalyst's activity in alkaline water electrolysis for hydrogen evolution. Its main working principle lies in: amorphous Co... x S will spontaneously dissolve and precipitate in deoxygenated water. Under certain conditions, amorphous Co... x The irregular morphology of S with a small specific surface area will transform into a nanosheet array morphology with a high specific surface area, thereby increasing the amorphous Co x The specific surface area of ​​S material allows for the exposure of more active sites. Amorphous Co x S atoms on the S surface can interact with Pt 4+ A reaction occurs that introduces Pt into Co. x S surface, to regulate Co x The electronic structure of the S material surface. For alkaline water electrolysis hydrogen evolution catalysts, only the active sites on the surface in contact with the electrolyte can exert catalytic activity. Therefore, this surface modification method is simpler than other techniques, and Pt 4+ It requires less solution, consumes less energy, simplifies experimental procedures, and has practicality and universality. Furthermore, for anode materials in lithium / sodium-ion batteries, amorphous Co can be transformed through a simple deoxygenated water-induced morphology transformation process. x The irregular morphology of S transforms into a flower-like morphology of self-assembled nanosheets, increasing the M + (M = Li, Na) intercalation-extraction active sites also shorten M + The diffusion distance of (M = Li, Na) was reduced, while amorphous Co was effectively suppressed. x The aggregation of S is beneficial to improving the utilization rate, theoretical capacity, rate performance, and long-cycle performance of materials.

[0077] As a further preferred embodiment of the above technical solution, during the deoxygenated water-induced morphological transformation process described in the step, dissolved oxygen in the soaking solution must be removed as much as possible through boiling, blowing in gas (nitrogen, argon, or other inert gases that do not pollute the atmosphere), etc. In this invention, there are special requirements for dissolved oxygen in the water to address the morphological transformation problem, but there are no special requirements for other electrolyte components in the water. For example, the deoxygenated water is ultrapure water, deionized water, tap water, drinking water, or other water with fewer impurities that has undergone deoxygenation treatment.

[0078] As a further preferred embodiment of the above technical solution, during the deoxygenated water-induced morphological transformation process, temperature and time have a significant impact on the amorphous Co x The final shape and thickness of the nanosheets have a great influence. Temperature and time should be controlled to match the nanosheet array morphology with appropriate density and size.

[0079] As a further preferred option of the above technical solution, when carrying out Pt-introduction modification, it is necessary to consider Pt... 4+ For amorphous Co x The etching effect of S requires separate control of the morphological transformation process induced by deoxygenated water and the modification process introduced by Pt.

[0080] In this invention, there are no special requirements for the pore density of the three-dimensional carrier; existing conventional commercial products can be used. For example, its pore density can be between 60 and 120 PPI.

[0081] During the deoxygenated water-induced morphological transformation stage, there are no special requirements for the liquid-solid ratio of the deoxygenated water and the precursor, as long as it can fully immerse the precursor. For example, the liquid-solid ratio can be above 50 ml / g, and considering efficiency and cost, it can be further set to 50–200 ml / g.

[0082] In this invention, deoxygenation treatment can be performed on water whose morphology has changed using known methods such as bubbling and boiling.

[0083] In this invention, amorphous cobalt sulfides can be deposited on a support using known methods. For example, the support can be placed in a solution containing dissolved nickel and sulfur sources for electrodeposition. The electrodeposition process and parameters are not essential factors for the successful implementation of the deoxygenated water-induced morphological transformation technique of this invention.

[0084] Specific implementation examples:

[0085] I. Morphological changes induced by deoxygenated water

[0086] The morphological transformation induced by deoxygenated water involves four important conditions: carrier, dissolved oxygen content of water, temperature-time, and Co. x The loading of the S precursor material is achieved by controlling the coulombic charge during the electrodeposition process. Furthermore, Pt can be introduced to influence the amorphous Co content. x S is modified.

[0087] Example 1:

[0088] This embodiment explores the effect of a carrier on amorphous Co. x The influence of deoxygenated water-induced morphological transformation process, i.e., using three-dimensional porous network structured nickel foam (NF) and two-dimensional smooth planar structured Ni sheet (NP) as electrodeposition carriers, to deposit Co with the same coulombic charge. x S (each named Co) x S@NF、Co x S@NP) underwent a morphological transformation process when placed in deoxygenated water, and the effect of this process on Co was compared. x S@NF、Co x The influence of S@NP morphology.

[0089] (1) Preparation of amorphous Co x S:

[0090] ①Preparation of sedimentation solution: The prepared sedimentation solution contains 5 mmol cobalt sulfate, 5 mmol sodium thiosulfate, 20 mL 1M triethanolamine, and 3 mol L... -1 The pH of the precipitate was adjusted to 5 ± 0.2 with HCl and set aside for later use.

[0091] ② Carrier pretreatment: Taking nickel foam (NF) as an example, 3 mol L... -1 The surface of the NF carrier was treated with HCl, acetone, ethanol, and water for 10 minutes by ultrasonic treatment to thoroughly remove impurities. The NP carrier was treated by direct polishing with ultrafine alumina.

[0092] ③ Electrodeposition process: A constant potential deposition method is used, with the potential set to -0.5V vs. Ag / AgCl, and saturated KCl solution filling. Amorphous Co with a charge of 1C is deposited on the surface of the pretreated NF support (or NP). x S (name: Co) x S@NF or Co x S@NP), after rinsing with water, is ready for the next step. Figure 1 From a and b, we can see that the electrodeposition yields amorphous Co. x S.

[0093] (2) Deoxygenated water-induced morphological transformation process: Step (1) finally obtained precursor (Co x S@NF or Co x S@NP) is placed in water that has been pre-treated by introducing N2, Ar or other gases or by boiling to remove dissolved oxygen (oxygen content is less than 1 ppm, and the liquid-to-solid ratio of deoxygenated water to precursor is 50-200 ml / g), and left to stand directly at room temperature (in this invention, room temperature refers to 30°C) for 48 hours.

[0094] A: Co x S@NF deoxygenated water-induced morphological transformation treatment; the transformed material is labeled W-Co. x S@NF;

[0095] B: Co x S@NP deoxygenated water-induced morphological transformation treatment; the transformed material is labeled W-Co. x S@NP;

[0096] SEM images of the obtained materials are shown below. Figure 2 It can be seen that amorphous Co is carried by NF. x S can undergo a deoxygenated water-induced morphology transformation process to obtain a regular nanosheet array morphology, while amorphous Co with NP as a support... xAfter S undergoes a morphological transformation induced by deoxygenated water, the amorphous Co on the surface... x S showed significant dissolution, failing to produce a regular nanosheet array morphology. This indicates that the three-dimensional porous network structure of NF plays a significant role in the morphology transformation induced by deoxygenated water. This also suggests that amorphous Co... x S has poor adhesion to nickel substrates, so NF is preferred as the substrate.

[0097] Example 2:

[0098] Compared with Example 1, the only difference is that in step (2)A, the water used for morphological transformation was not pre-treated for deoxygenation, and the dissolved oxygen content in the water was 7.56 ppm (30°C). Other operations and parameters were the same as in Example 1. The material after water-induced morphological transformation treatment was labeled as OD-Co. x S@NF.

[0099] SEM images of the material before and after water-induced morphological transformation treatment are shown below. Figure 3 In Figure (a), the material prepared in Group A of step 2 of Example 1 yielded the desired nanosheet array. Figure (b) shows the SEM images of the material before and after the morphology transformation treatment in this case. This phenomenon was not observed in the water treated with dissolved oxygen, indicating that dissolved oxygen in the water also has a significant impact on the morphology transformation process.

[0100] Example 3:

[0101] Compared to Example 1, using NF as the electrodeposition carrier only changed the temperature-time of the deoxygenated water-induced morphological transformation process in group (2)A, and appropriately shortened the time as the temperature increased:

[0102] A: 30℃-48h; the material after morphological transformation is W-Co. x S@NF;

[0103] B: 60℃-4h; the material after morphological transformation is labeled W-Co. x S@NF-60℃;

[0104] C: 90℃-2h; the material after morphological transformation is labeled as W-Co. x S@NF-90℃;

[0105] SEM images of the obtained materials are shown below. Figure 4 (See Group A SEM) Figure 4 (a), SEM of group B is shown in Figure 4 (b), SEM of Group C is shown in Figure 4 (c) It can be seen that under different temperature-time conditions, amorphous Co can be transformed through the morphology transformation process induced by deoxygenated water. xThe irregular morphology of S is transformed into a regular nanosheet array morphology.

[0106] Example 4:

[0107] Compared to Example 1, NF was used as the electrodeposition carrier, and only the electrodeposition of Co in step (1) was changed. x The coulomb charge of S is then used to proceed to step 2, with all other operations and parameters remaining the same as in Example 1:

[0108] A: 1C; the material after morphological transformation is W-Co. x S@NF;

[0109] B: 5C; the material before the morphological transformation was identified as Co. x S@NF-5C, the material after morphological transformation is designated as W-Co. x S@NF-5C;

[0110] SEM images of the obtained materials are shown below. Figure 5 It can be seen that changing amorphous Co x Following the deposition coulombic charge of the S precursor material, the amorphous Co with low and high deposition coulombic charges... x S can successfully undergo morphological transformation through deoxygenated water-induced transformation. However, there is a slight difference: amorphous Co with high deposition coulombic charge... x S will further transform into a flower-like morphology of self-assembled nanosheets.

[0111] Example 5:

[0112] Compared with Example 1, the difference lies in step (1): (1-1) copper foam is used to replace the NF as the electrodeposition carrier; (1-2) the pH of the electrodeposition solution is adjusted to 3, the constant deposition time is 300s, and the loading is 0.7-0.8 mg cm⁻¹. -2 The deposited material is labeled as α-Co. x S was subjected to deoxygenated water-induced morphological transformation treatment in step 2, and the morphological transformation time in step (2) was 96 hours; other operations and parameters were the same as in Example 1; the material after the final morphological transformation was labeled as Wa-Co. x S-96h;

[0113] SEM images of the obtained materials are shown below. Figure 6 It can be seen that changing amorphous Co x After electrodeposition conditions of the S precursor material—support and pH—and morphological transformation treatment induced by deoxygenated water for 96 hours, a flower-like morphology of self-assembled nanosheet arrays can still be obtained.

[0114] Example 6:

[0115] Compared with Group B of Example 3, the only difference is that in step (2), deoxygenated water was used to induce the morphological transformation, and a 0.1 mM MPtCl4 solution that had already been deoxygenated was used for the direct Pt introduction modification treatment (wherein, the mass ratio of Pt in PtCl4 to the amorphous cobalt sulfide nanosheets in the precursor was 0.117:1). All other operations and parameters were the same as those in Group B of Example 3.

[0116] A: Deoxygenated water; the material after morphological transformation is W-Co. x S@NF-60℃;

[0117] B: 0.1 mM PtCl4 solution; materials directly modified by Pt introduction are labeled Pt / Co. x S@NF-60℃;

[0118] SEM images of the materials obtained from Group A are shown below. Figure 4 (b). SEM images of the materials obtained from Group B are shown in [the image]. Figure 7 It was discovered that directly depositing amorphous Co x S@NF is placed in a 0.1 mM PtCl4 solution. Since Pt continuously reacts with Co... x S reaction, leading to Co x S was over-etched and its structure collapsed, making it impossible to obtain the morphology of the nanosheet array.

[0119] Example 7:

[0120] Compared with Group B of Example 3, the only difference is that in step (2), the amorphous Co is first... x S@NF underwent a deoxygenated water-induced morphological transformation at 60℃ (4 h treatment), followed by Pt-introduction modification treatment at 90℃ in a deoxygenated 0.1 mM PtCl4 solution for 1 h (where the mass ratio of Pt in PtCl4 to the amorphous cobalt sulfide nanosheets in the material after the deoxygenated water-induced morphological transformation was 0.117:1). The final material was labeled as Pt / W-Co. x S@NF-60℃;

[0121] The SEM images of the materials obtained in this case are shown below. Figure 8 It was discovered that the irregularly shaped amorphous Co was first... x After S@NF is transformed into a nanosheet array morphology in deoxygenated water, the reaction temperature and reaction time are then controlled. This indirect method of Pt introduction modification allows for the control of Pt. 4+ For amorphous Co x The etching degree of the S surface is such that it can retain as much of the morphology of the nanosheet array obtained by the deoxygenated water-induced morphology transformation treatment as possible, and... Figure 4 (b) and Figure 7In comparison, it retains most of the morphology of the nanosheet array.

[0122] II. Application

[0123] Example 8:

[0124] Compared with Example 1, amorphous Co deposited on different carriers was compared. x The difference in HER catalytic performance of alkaline electrolyzed water before and after deoxygenated water-induced morphological transformation treatment indicates the effect of morphological transformation on amorphous Co. x The effect of S on electrochemical performance:

[0125] A: Was it treated with deoxygenated water to induce morphological transformation (Co)? x S@NF, W-Co x HER catalytic performance of S@NF;

[0126] B: Whether it has undergone deoxygenated water-induced morphological transformation treatment (Co) x S@NP, W-Co x HER catalytic performance of S@NP);

[0127] The catalytic performance of alkaline water electrolysis for hydrogen evolution was tested, including hydrogen evolution polarization curves, electrochemical impedance, electrochemical double-layer capacitance, and electrochemical active area. The electrolyte used in the test was 1 mol L⁻¹ Ar gas-saturated solution. -1 A KOH solution, passed through a three-electrode system (with Co...) x The S material electrode was used as the working electrode, the graphite rod as the counter electrode, and the Ag / AgCl electrode (filled with saturated KCl solution) as the reference electrode. The test was conducted using a Chenhua electrochemical workstation (CHI660D), as detailed below:

[0128] (1) Hydrogen evolution polarization curve test: A linear sweep voltammetry method was used, with a potential range of -0.9 to -1.5 V vs. Ag / AgCl (filled with saturated KCl solution), and a scan rate of 5 mV / s. -1 Scan several times until the polarization curve stabilizes. Measure the HER polarization curve, perform iR compensation, and take the IMP test fitting result R0. u And take current densities of -10 and -100 mA cm -2 The hydrogen evolution overpotential corresponding to the current density (the negative sign represents the cathode current) is used to evaluate the alkaline HER catalytic activity. The smaller the value of the hydrogen evolution overpotential, the weaker the electrochemical polarization tendency of the material during the electrocatalytic HER process, that is, it has higher HER catalytic activity.

[0129] (2) Electrochemical impedance spectroscopy (IMP) test: The IMP technique was used with the following parameters: initial potential of -100mV vs. RHE, and frequency range of 0.01 to 100,000 Hz. The internal resistance R of the solution was obtained by fitting the Nyquist plot (a double Z-plot). u (Reactance of the RE to WE solution), charge transfer resistance R ct R ct The smaller the value, the faster the charge transfer during the HER catalytic reaction, the greater the rate of the electrochemical reaction, and the weaker the electrochemical polarization.

[0130] (3) Double-layer capacitance-electrochemical active area test: Generally, a potential scan range of ±20mV from the stable open-circuit potential OCP is selected, and cyclic voltammetry tests are performed by sequentially increasing or decreasing the scan rate at equal intervals, such as 20, 40, 60, 80, and 100mVs. -1 By fitting, a straight line was obtained showing the change of half of the current density difference between the positive and negative scans at OCP as a function of the scan rate. The slope of this line is related to the double-layer capacitance C. dl The value corresponds to this. Double-layer capacitance C dl The electrochemically active area (ECSA) is determined by the formula: ECSA = (C dl ×A) / Cs establishes a relationship, where C s (mF cm -2 ) is the specific capacitance of an atomically smooth plane, A(cm) 2 C represents the geometric area of ​​the electrode. s The value is typically between 20 and 60 μF cm⁻¹ in alkaline media. -2 Between these values, we chose an average value of 40 μF cm. -2 Calculations show that ECSA varies with C. dl They exhibit a linear positive correlation.

[0131] The test results of the alkaline water electrolysis hydrogen evolution catalytic performance are as follows: Figure 9 As shown in Figure a, it can be seen that W-Co with NF as the carrier x S@NF compared to Co x S@NF, at 10mA cm -2 The overpotential decreased from 199mV to 120mV. Figure 9 b and d show that W-Co x S@NF compared to Co x S@NF, charge transfer resistance R ct With a significant reduction, the Tafel slope also decreased to some extent, and these results together indicate that W-Co x S@NF compared to Co x In S@NF, the electrochemical polarization of the alkaline water electrolysis hydrogen evolution reaction is significantly weakened, i.e., Co xThe alkaline electrolysis hydrogen evolution catalytic performance of S-materials has been significantly improved. Meanwhile, W-Co with NP as the support... x S@NP compared to Co x S@NP, by Figure 10 It can be seen that the HER catalytic performance actually decreased after water-induced morphological transformation, which is consistent with the results of scanning electron microscopy. Figure 2 , Figure 9 c and Figure 10 Results of c: ① Amorphous Co deposited on a three-dimensional carrier NF x S can achieve the deoxygenated water-induced morphological transformation process, while the two-dimensional smooth carrier NP cannot complete the deoxygenated water-induced morphological transformation process; ② Amorphous Co x The improved alkaline HER catalytic performance of S is attributed to the deoxygenated water-induced morphology transformation process, which converts the irregular morphology into a regular nanosheet array morphology, increasing the potential for growth of amorphous Co. x The specific surface area of ​​S material exposes more active sites; ③ Amorphous Co x S has a larger electrochemical active area and stronger adhesion on a three-dimensional carrier.

[0132] Example 9:

[0133] Compared to Example 8, the only difference is that the amorphous Co after the water-induced morphology transformation process in Example 2 is compared. x The alkaline water electrolysis HER catalytic performance of S was tested in the following experimental groups:

[0134] A: W-Co x HER catalytic performance of S@NF

[0135] B: OD-Co x HER catalytic performance of S@NF

[0136] Depend on Figure 3 and Figure 11 It can be seen that amorphous Co x S cannot complete its morphological transformation in unoxygenated water; in fact, due to dissolution and oxidation in water, its HER catalytic performance may even be worse than that of Co. x The worse S@NF indicates that dissolved oxygen in water is a key factor in the water-induced morphological transformation process.

[0137] Example 10:

[0138] Compared with Example 8, the only difference is that the alkaline water electrolysis HER catalytic performance of the material after the morphological transformation induced by deoxygenated water in Example 3 was tested. The experimental group was:

[0139] A: 30℃-48h (W-Co) x HER catalytic performance of S@NF;

[0140] B: 60℃-4h (W-Co) x HER catalytic performance of S@NF-60℃;

[0141] C: 90℃-2h (W-Co) x HER catalytic performance of S@NF-90℃;

[0142] Depend on Figure 4 and Figure 12 It can be seen that by optimizing the time of the morphological transformation process induced by deoxygenated water at different temperatures, very similar HER catalytic performance of alkaline water electrolysis can be obtained. Among them, groups B and C have higher preparation efficiency and their performance is still improved.

[0143] Example 11:

[0144] Compared with Example 8, the only difference is that the alkaline water electrolysis HER catalytic performance of the materials before and after the morphological transformation induced by deoxygenated water in Example 4 was tested. The experimental group was:

[0145] A: Before deoxygenated water-induced morphological transformation treatment (Co) x HER catalytic performance of S@NF-5C);

[0146] B: After deoxygenated water-induced morphological transformation treatment (W-Co) x HER catalytic performance of S@NF-5C);

[0147] Depend on Figure 5 and Figure 13 It can be seen that the deposition charge of amorphous Co is 5C. x S, after undergoing a morphological transformation induced by deoxygenated water, W-Co x S@NF-5C has better HER catalytic performance than Co. x The S@NF-5C has been significantly improved, mainly due to the increase in the electrochemical active area.

[0148] Example 12:

[0149] Compared to Example 8, the only difference is that the amorphous Co with different deposition charges in groups A and B of Example 4 are compared. x The HER catalytic performance of alkaline water electrolysis after S underwent morphological transformation induced by deoxygenated water was tested in the experimental group as follows:

[0150] A: 1C(W-Co) x HER catalytic performance of S@NF;

[0151] B: 5C(W-Co) x HER catalytic performance of S@NF-5C;

[0152] Depend on Figure 5 and Figure 14 It can be seen that amorphous Co with different deposition charges x The difference in HER catalytic performance after the S@NF completes the morphological transformation process is small, but it can be seen that W-Co x S@NF-5C has a larger electrochemical active area, indicating that the deposition charge, within a certain range, affects the final morphology obtained from the deoxygenated water-induced morphological transformation process, but has a greater effect on amorphous Co. x The effect of S on the HER catalytic performance is relatively small.

[0153] Example 13:

[0154] Compared with Example 8, the only difference is that the alkaline water electrolysis HER catalytic performance of the materials obtained by treating them in deoxygenated water at 60°C and a deoxygenated 0.1mM PtCl4 solution for 4 hours was compared. The experimental group was as follows:

[0155] A: Deoxygenated water treatment (W-Co) x HER catalytic performance of S@NF-60℃;

[0156] B: Treatment in 0.1mM PtCl4 solution (Pt / Co) x HER catalytic performance of S@NF-60℃;

[0157] Depend on Figure 4 (b) 7.15 shows that the amorphous Co obtained by electrodeposition x S@NF can be directly modified by Pt introduction, which can significantly improve the amorphous Co x S@NF's HER catalytic performance, but due to Pt 4+ Direct etching of Pt / Co x The nanosheet array morphology could not be obtained at S@NF-60℃, and the electrochemical active area of ​​the material did not increase significantly, which was not conducive to shortening the diffusion distance of ions and accelerating the charge transfer process.

[0158] Example 14:

[0159] Compared with Example 8, the only difference lies in the difference in the alkaline water electrolysis HER catalytic performance of the materials in Example 7. The experimental group is as follows:

[0160] A: After deoxygenated water-induced morphological transformation treatment (W-Co) x HER catalytic performance of S@NF-60℃;

[0161] B: Deoxygenated water-induced morphological transformation + Pt-introduced modification process (Pt / W-Co) x HER catalytic performance of S@NF-60℃;

[0162] Depend on Figure 4 (b) 8.16 shows that Pt can still be introduced after the deoxygenated water-induced morphology transformation process. Furthermore, by controlling the time and temperature of this process, the nanosheet array morphology can be preserved as much as possible while achieving better HER catalytic performance. Compared to Example 13, the Pt / W-Co... x S@NF-60℃ exhibits better HER activity, a larger electrochemical active area, and a smaller R... u The Tafel slope indicates a faster hydrogen evolution reaction kinetics.

[0163] Example 15:

[0164] Compared to Example 5, only the materials before and after the deoxygenated water-induced morphological transformation process were treated, i.e., a-Co x S&Wa-Co x S-96h is used as an electrode material for lithium-ion batteries, and the differences in the electrochemical lithium storage performance of the materials are compared:

[0165] A: a-Co x S's lithium storage performance;

[0166] B: Wa-Co x Lithium storage performance of S-96h;

[0167] Half-cell assembly and testing: CR2032 coin cells were used for encapsulation. First, the dried electrodes were placed in a glove box (water and oxygen content both below 1 ppm). The electrodeposited a-Co... x S, Wa-Co x The S-96h can be directly used as the working electrode, with lithium foil as the counter and reference electrodes, and Celgard 2400 microporous polypropylene membrane as the separator material for the half-cell. 1M LiPF6 is dissolved in a 1:1 mass ratio mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) as the electrolyte. The electrolyte is present at 0.01–3.0 V vs. Li + / Li was tested at room temperature under different current densities using a programmable battery testing system (CT2001A, Landian Electronics Co., Ltd.).

[0168] The obtained Wa-Co x S-96h, a-Co x Electrochemical performance tests, including constant current charge-discharge cycling, were performed on S. The results are as follows. Figure 17 As shown, at 0.2Ag -1 At current density, Wa-Co x The charge / discharge capacity of S-96h is significantly higher than that of a-Co. xS, and after 100 cycles, it still maintains a high charge / discharge capacity. Furthermore, it enables Wa-Co... x The S-96h undergoes longer long-cycle charge-discharge testing at higher current densities, such as... Figure 18 As shown, at 1.0A g -1 At current density, the initial discharge specific capacity and charge specific capacity reach as high as 1910 mAh g. -1 and 1420mAh g -1 The coulombic efficiency is 74.34%, and its discharge specific capacity is still nearly 600 mAh g after 600 cycles. -1 It is significantly better than a-Co x The long cycling performance of S, and all of these, demonstrate the significance of Wa-Co nanosheets self-assembling to form a flower-like morphology. x S-96h has great application potential in the field of lithium-ion battery anode materials.

[0169] Example 16:

[0170] Compared to Example 5, only the materials before and after the deoxygenated water-induced morphological transformation process were treated, i.e., a-Co x S&Wa-Co x S-96h was used as an electrode material for sodium-ion batteries, and the differences in the electrochemical sodium storage performance of the materials were compared:

[0171] A: a-Co x Sodium storage capacity of S;

[0172] B: Wa-Co x Sodium storage performance of S-96h;

[0173] Half-cell assembly and testing: Electrochemical performance was tested using CR2032 coin cells assembled at room temperature in an Ar-filled glove box (UNIlab, Braun; H2O < 1 ppm, O2 < 1 ppm). The prepared electrode is a-Co. x S, Wa-Co x The S-96h was used directly as the working electrode. A Na foil was used as both the counter and reference electrode, and a glass microfiber membrane (Whatman GF / F) was used as the diaphragm. 1M NaClO4 was dissolved in a mixture of ethylene carbonate (EC) / dimethyl carbonate (DMC) / ethyl methyl carbonate (EMC) (v / v / v = 1:1:1), and 5% fluoroethylene carbonate (FEC) was added as the electrolyte. The electrolyte was prepared at 0.01–3.0 V vs. Na. + / Na was tested at room temperature under different current densities using a programmable battery testing system (CT2001A, Landian Electronics Co., Ltd.).

[0174] For the obtained a-Co x S, Wa-Co x The S-96h underwent electrochemical performance tests, including constant current charge-discharge cycles and rate capability assessments. The results are as follows: Figure 19 , Figure 20 , Figure 21 As shown, at 0.2Ag -1 At current density, Wa-Co x The initial discharge specific capacity and charge specific capacity of the S-96h are approximately 810 and 654 mAh g, respectively. -1 The corresponding initial coulombic efficiency is 80.7%. At a discharge current density of 1 A g... -1 At times, it can reach nearly 600mAh g -1 The discharge capacity is stable for 300 cycles, exhibiting good cycle stability, and also showing significantly better performance than a-Co. x The rate performance of S also demonstrates the flower-like morphology of Wa-Co nanosheets formed by self-assembly. x S-96h also has great application potential in the field of sodium-ion battery anode materials.

[0175] As can be seen from the above examples, the Co-modified high specific surface area nanosheet array morphology prepared by this invention... x The S material exhibits high alkaline water electrolysis HER catalytic activity and lithium / sodium storage performance, fully exposing active sites and improving material utilization. This patent proposes a unique deoxygenated water-induced morphology transformation, specifically, the transformation of amorphous Co through the inductive effect of water molecules. x The irregular morphology of S is transformed into a regular nanosheet array morphology, and Co is used to transform it into a regular nanosheet array morphology. x The unique chemical reducing properties of the S-sites on the S-surface allow for the introduction of a small amount of Pt after the deoxygenated water-induced morphological transformation process, further enhancing the material's alkaline water electrolysis HER catalytic performance. However, when used as a negative electrode material for lithium / sodium-ion batteries, amorphous Co... x The irregular morphology of S further transforms into a flower-like morphology of self-assembled nanosheets. Compared with other morphologies of cobalt sulfide materials, the flower-like morphology of self-assembled nanosheets can effectively increase the contact area with the electrolyte, shorten the diffusion distance of lithium / sodium ions, and effectively inhibit Co. x The aggregation of sulfur (S) exhibits better and more stable electrochemical performance. Compared with other morphology transformation and surface modification methods, deoxygenated water-induced morphology transformation is simpler, lower in energy consumption, and lower in cost, possessing universality, practicality, and economy. The control of the deoxygenated water-induced morphology transformation process conditions allows for the selection of appropriate strategies based on specific needs and process flows, simplifying the process and further reducing the cost of hydrogen evolution catalysts and the manufacturing cost of lithium / sodium-ion battery anode materials, thus demonstrating broad market prospects.

[0176] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and modifications obtained without departing from the inventive concept should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an amorphous cobalt sulfide nanosheet array, characterized in that, A precursor loaded with amorphous cobalt sulfide was obtained, and then placed in deoxygenated water to undergo morphological transformation, so that the irregular morphology of the loaded amorphous cobalt sulfide was transformed into a nanosheet array morphology. The precursor was obtained by electrodepositing the carrier in a deposition solution containing a cobalt source and a sulfur source. The cobalt source is a water-soluble salt of Co 2+ The sulfur source is a water-soluble thiosulfate salt; the molar ratio of cobalt source to sulfur source is 0.1-2:

1. The electrodeposition potential is 0.4~0.6 V vs. Ag / AgCl; The treatment time for morphological transformation induced by deoxygenated water is more than 1 hour.

2. The method for preparing amorphous cobalt sulfide nanosheet arrays as described in claim 1, characterized in that, The carrier is a three-dimensional carrier.

3. The method for preparing amorphous cobalt sulfide nanosheet arrays as described in claim 2, characterized in that, The three-dimensional carrier is at least one of nickel foam, cobalt foam, and copper foam.

4. The method for preparing the amorphous cobalt sulfide nanosheet array as described in claim 3, characterized in that, The porosity of the three-dimensional carrier is 60~120 PPI.

5. The method for preparing amorphous cobalt sulfide nanosheet arrays as described in claim 1, characterized in that, The cobalt source is at least one of cobalt sulfate, cobalt chloride, and cobalt acetate; The sulfur source is at least one of sodium thiosulfate, potassium thiosulfate, and ammonium thiosulfate; The molar ratio of cobalt source to sulfur source is 0.5~1.0:

1.

6. The method for preparing an amorphous cobalt sulfide nanosheet array as described in claim 1, characterized in that, The sediment also contains a pH adjuster, which is at least one of dilute hydrochloric acid and dilute sulfuric acid. The pH of the sediment solution is 3 to 5.

5.

7. The method for preparing amorphous cobalt sulfide nanosheet arrays as described in claim 1, characterized in that, The carrier is pretreated with dilute hydrochloric acid, acetone, anhydrous ethanol and deionized water.

8. The method for preparing the amorphous cobalt sulfide nanosheet array as described in claim 1, characterized in that, During the electrodeposition stage, the Ag / AgCl electrode is filled with a saturated KCl solution.

9. The method for preparing the amorphous cobalt sulfide nanosheet array according to any one of claims 1 to 8, characterized in that, The loading amount of the amorphous cobalt sulfide in the precursor is 0.7-5.0 mg cm −2 .

10. The method for preparing the amorphous cobalt sulfide nanosheet array as described in claim 1, characterized in that, The dissolved oxygen content in the deoxygenated water is less than or equal to 1 ppm.

11. The method for preparing an amorphous cobalt sulfide nanosheet array as described in claim 10, characterized in that, The deoxygenated water is water that has been treated by boiling and / or bubbling.

12. The method for preparing an amorphous cobalt sulfide nanosheet array as described in claim 1, characterized in that, The atmosphere introduced during the bubbling process is an inert gas.

13. The method for preparing an amorphous cobalt sulfide nanosheet array as described in claim 1, characterized in that, The atmosphere bubbled in during the bubbling process is nitrogen.

14. The method for preparing the amorphous cobalt sulfide nanosheet array as described in claim 1, characterized in that, The liquid-to-solid ratio of the deoxygenated water and the precursor is above 50 ml / g.

15. The method for preparing the amorphous cobalt sulfide nanosheet array as described in claim 1, characterized in that, The temperature during the deoxygenated water-induced morphological transformation treatment stage is above 0 ℃.

16. The method for preparing the amorphous cobalt sulfide nanosheet array as described in claim 15, characterized in that, The temperature for the deoxygenated water-induced morphological transformation treatment stage is 20~100 ℃.

17. The method for preparing the amorphous cobalt sulfide nanosheet array as described in claim 16, characterized in that, The temperature for the deoxygenated water-induced morphological transformation treatment stage is 30~95 ℃.

18. The method for preparing the amorphous cobalt sulfide nanosheet array as described in claim 17, characterized in that, The temperature for the deoxygenated water-induced morphological transformation treatment stage is 50~95 ℃.

19. The method for preparing the amorphous cobalt sulfide nanosheet array as described in claim 18, characterized in that, The temperature for the deoxygenated water-induced morphological transformation treatment stage is 60~90 ℃.

20. The method for preparing the amorphous cobalt sulfide nanosheet array as described in claim 1, characterized in that, The treatment time for morphological transformation induced by deoxygenated water was 2 to 100 h.

21. The method for preparing an amorphous cobalt sulfide nanosheet array as described in claim 1, characterized in that, The precursor was subjected to Pt-introduction modification in a deoxygenated aqueous solution containing a Pt source to directly obtain Pt-introduced modified amorphous cobalt sulfide. Alternatively, after the morphology transformation treatment in deoxygenated water for more than 1 hour, Pt source can be added to the morphology transformation system for Pt introduction modification treatment. Alternatively, after undergoing morphological transformation treatment induced by deoxygenated water, the nanosheets are then immersed in a Pt source solution to obtain a Pt-modified amorphous cobalt sulfide nanosheet arrays.

22. The method for preparing an amorphous cobalt sulfide nanosheet array as described in claim 21, characterized in that, The Pt source is a water-soluble salt of Pt.

23. The method for preparing an amorphous cobalt sulfide nanosheet array as described in claim 21, characterized in that, The mass ratio of Pt in the Pt source to amorphous cobalt sulfide nanosheets in the precursor is 0.01~0.15:

1.

24. The method for preparing an amorphous cobalt sulfide nanosheet array as described in claim 23, characterized in that, The mass ratio of Pt in the Pt source to the amorphous cobalt sulfide nanosheets in the precursor is 0.02~0.12:

1.

25. An amorphous cobalt sulfide nanosheet array prepared by the method according to any one of claims 1 to 24, characterized in that, It includes a carrier and an array of amorphous cobalt sulfide nanosheets loaded on its surface.

26. The amorphous cobalt sulfide nanosheet array prepared by the method according to claim 25, characterized in that, The specific surface area of the amorphous cobalt sulfide nanosheet array is 67.5-104.2 m 2 g −1 .

27. The application of an amorphous cobalt sulfide nanosheet array prepared by the method according to any one of claims 1 to 24, characterized in that, It can be used as a catalyst for hydrogen evolution reaction and / or an active material for the negative electrode of lithium / sodium ion batteries.

28. An electrochemical device, characterized in that, The array comprises an amorphous cobalt sulfide nanosheet obtained by the preparation method according to any one of claims 1 to 24.

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