Method for preparing nickel-cobalt sulfide nano-particles serving as positive electrode material of super capacitor

Abstract

The invention discloses a preparation method of nickel-cobalt sulfide nanoparticles of a supercapacitor positive electrode material, and relates to a preparation method of a supercapacitor positive electrode material. The method solves the problems of loss of a large amount of raw materials, environmental pollution and agglomeration of the synthesized nickel-cobalt sulfide in the existing nickel-cobalt sulfide synthesis process. The method comprises the following steps: selecting cobalt nitrate, nickel nitrate and thioacetamide as a cobalt source, a nickel source and a sulfur source respectively, taking ammonium fluoride as a structure regulating agent, taking ultrapure water as a reaction medium, and synthesizing the nickel-cobalt sulfide through a simple one-step hydrothermal method. The positive electrode material prepared by the method disclosed by the invention is beneficial to reducing the cost in the synthesis process and the agglomeration of the material, and has the advantages of low cost, high specific capacity and high stability. The product is mainly used for the positive electrode material of the supercapacitor.

Description

Technical Field

[0001] This invention relates to a method for preparing positive electrode materials for supercapacitors. Background Technology

[0002] In recent years, with the rapid development of society, energy and environmental issues have become increasingly prominent, attracting widespread attention. Fossil fuels (oil, coal, and natural gas, etc.) are gradually being depleted through years of human exploitation, and the environmental pollution caused by the massive consumption of energy—such as acid rain caused by nitrogen oxides or sulfides produced during combustion, and global warming due to emitted greenhouse gases (CO2)—has plunged the world into a dual crisis of fossil fuel scarcity and environmental pollution. Therefore, the desire for clean energy and efficient energy storage devices is growing rapidly. Meanwhile, my country has proposed the two major goals of "carbon peaking" and "carbon neutrality," further promoting the development of clean energy and energy storage devices.

[0003] Currently, there are many types of renewable energy that humans can develop and use on a large scale, but solar, wind, geothermal, and tidal energy are the most widely used. However, these energy sources are easily affected by uncontrollable environmental factors such as location, season, and climate, resulting in discontinuous and intermittent energy production. This leads to extremely unstable power output from the power grid, which is detrimental to energy storage and the safety of energy storage devices. Therefore, special devices are needed to store and convert energy to further stabilize the output voltage. Electrochemical energy storage, mechanical energy storage, and electromagnetic energy storage are the three main types of energy storage technologies today. Electrochemical energy storage has gained favor among researchers due to its higher energy density, longer cycle life, and faster response speed. Among electrochemical energy storage technologies, batteries and supercapacitors are the most widely studied.

[0004] Supercapacitors have increasingly attracted the interest of scientists worldwide due to their advantages such as high power density, good cycle stability, high coulombic efficiency, and short charge-discharge cycles. Electrode materials are a crucial component of supercapacitors and one of the main factors affecting their electrochemical performance. Obtaining electrode materials with high electrochemical performance is currently a hot research topic in supercapacitors. Polymetallic sulfides exhibit better electrochemical performance compared to monometallic sulfides and polymetallic oxides. Among them, Ni and Co have become popular transition metal elements in current polymetallic sulfide research due to their high theoretical specific capacity, low toxicity, and low cost. Currently, nickel-cobalt metal sulfides are mainly synthesized using a two-step method, with the precursor synthesized via a solvothermal method. Without appropriate solvent recovery equipment, this results in significant raw material loss and environmental pollution; furthermore, the synthesized sulfides generally exhibit agglomeration, severely affecting their electrochemical performance. Summary of the Invention

[0005] The purpose of this invention is to solve the problems of large raw material losses, environmental pollution, and agglomeration of synthesized nickel-cobalt sulfides caused by existing nickel-cobalt sulfide synthesis processes, and to provide a method for preparing nickel-cobalt sulfide nanoparticles.

[0006] The preparation method of nickel-cobalt sulfide nanoparticles, the positive electrode material of supercapacitors in this invention, is carried out according to the following steps: 1. Nickel salt and cobalt salt are dissolved sequentially in ultrapure water, and stirred with a magnetic stirrer until the solution is completely mixed and clear. 2. Ammonium fluoride and thioacetyl are dissolved sequentially in ultrapure water, and stirred with a magnetic stirrer until the solution is completely mixed and clear. 3. The solution obtained in step 1 is added to the solution obtained in step 2, and stirred again with a magnetic stirrer until the solution is completely mixed and clear. Then, the mixed solution is transferred to a high-pressure reactor and subjected to hydrothermal reaction using a forced-air drying oven. The resulting nickel-cobalt sulfide nanoparticle material is a structure in which large particles with densely packed nanoparticles grow on their surface, exhibiting high aggregation resistance, high specific surface area, and numerous active sites. Attached Figure Description

[0007] Figure 1 These are XRD patterns of nickel-cobalt sulfides synthesized under different conditions.

[0008] Figure 2 It's Ni 1.5 Co 1.5 S4 XPS graph

[0009] Figure 3 It's Ni 1.5 Co 1.5 SEM image of S4

[0010] Figure 4 It's Ni 1.5 Co 1.5 S4 EDS plot Detailed Implementation

[0011] To better understand the present invention, the following detailed description is provided in conjunction with embodiments. However, the scope of protection of the present invention is not limited to the scope shown in the embodiments.

[0012] Example 1:

[0013] To better understand the present invention, the present invention will be further described in detail below with reference to the embodiments. However, the scope of protection of the present invention is not limited to the scope represented by the embodiments.

[0014] The specific implementation method is as follows: The preparation method of nickel-cobalt sulfide nanoparticles in this embodiment is carried out according to the following steps:

[0015] (1) Dissolve the nickel salt and cobalt salt in ultrapure water in sequence, and stir with a magnetic stirrer for 15 minutes to make the solution completely mixed and clear.

[0016] (2) Dissolve ammonium fluoride and thioacetyl in ultrapure water in sequence, and stir with a magnetic stirrer for 15 minutes to make the solution completely mixed and clear.

[0017] (3) Add the solution obtained in step one to the solution obtained in (2), and stir with a magnetic stirrer for 30 minutes to ensure the solution is completely mixed and clear. Then transfer the mixed solution to a high-pressure reactor and perform a hydrothermal reaction in a forced-air drying oven for 4 hours. This yields nickel-cobalt sulfide nanoparticle materials. The nickel-cobalt sulfide prepared by this method has a structure of densely packed nanoparticles growing on a large particle surface, exhibiting high aggregation resistance, high specific surface area, and numerous active sites.

[0018] Example 2: Unlike Example 1, the ratio of nickel salt to cobalt salt in step (1) was adjusted in order to prepare nickel-cobalt sulfides with different nickel-cobalt ratios.

[0019] Example 3: Unlike Example 1, the amount of NH4F added in step (2) was adjusted in order to prepare nickel cobalt sulfides with different amounts of NH4F.

Claims

1. Process for the production of nickel cobalt sulfides, characterized in that The preparation method of the nickel cobalt sulfide is realized according to the following steps: I. nickel salt and cobalt salt are dissolved in ultrapure water in sequence, and a magnetic stirrer is used for stirring for 15 min, so that the solution is completely mixed uniformly and clarified; II. ammonium fluoride and thioacetamide are dissolved in ultrapure water in sequence, and a magnetic stirrer is used for stirring for 15 min, so that the solution is completely mixed uniformly and clarified; III. the solution obtained in step I is added to the solution obtained in step II, and a magnetic stirrer is used for stirring for 30 min, so that the solution is completely mixed uniformly and clarified, and then the mixed solution is transferred to a high-pressure reaction kettle, and a forced air drying oven is used for hydrothermal reaction. Namely, the nickel cobalt sulfide nanoparticle material is obtained. The nickel cobalt sulfide prepared by the method is a structure in which a large number of nanoparticles grow densely on the surface of a large particle, the agglomeration resistance is relatively large, the specific surface area is relatively high, and the active sites are more.

2. The method of producing a nickel cobalt sulfide according to claim 1, characterized by The noble metal salt in step I is Ni(NO3)2, Co(NO3)2.

3. The method of producing a nickel cobalt sulfide according to claim 1 or 2, characterized by The ammonium fluoride and thioacetamide are added in step II.

4. The method of producing a nickel cobalt sulfide according to claim 1, 2 or 3, characterized by The reaction temperature in step III is 80-140 DEG C, and the reaction time is 2-4 h.

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