Supercapacitor and production method thereof

Abstract

A supercapacitor and a production method thereof are provided. Positive active material of the supercapacitor is of copper sulfide-manganese sulfide composite structure that is composed of a copper sulfide nanosheet layer and manganese sulfide nanoparticles. The production method hereof comprises: (1) subjecting foam nickel to surface treatment to obtain a base; (2) placing the base in a hydrothermal reactor, adding a mixed solution of CO(NH2)2, CuCl2 6H2O and MnCl2 6H2O, carrying out first hydrothermal reaction, and washing to obtain a nickel-supported base; (3) subjecting the nickel-supported base and Na2S solution to second hydrothermal reaction, washing, and drying to obtain a positive electrode; (4) manufacturing a negative electrode; (5) assembling to obtain the supercapacitor. The supercapacitor and the production method thereof have the advantages that electrochemical properties of the supercapacitor are improved so that specific capacitance of the supercapacitor is greatly improved; window voltage is effectively increased, energy density of a device can be increased, and the primary assembled device is capable of turning on an LED light.

Description

technical field [0001] The invention belongs to the technical field of capacitors, in particular to a super capacitor and a preparation method thereof. Background technique [0002] Supercapacitors, also known as electrochemical capacitors, are a new type of energy storage element; in 1957, General Electric Company proposed the idea of ​​supercapacitors for practical applications. It was not until 1969 that SOHIO tried to bring capacitors to the market for the first time. However, its application in the field of hybrid electric vehicles did not really attract people's attention until the 1990s; supercapacitors can provide battery-based hybrid electric vehicles with the necessary power for acceleration and emergency braking. Communications, national defense and other fields have broad application prospects. [0003] Supercapacitors are generally assembled from electrode materials, current collectors, separators and electrolytes; compared with other energy storage devices, th...

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Problems solved by technology

At present, the main researched conductive polymers are: polythiophene, polyaniline, polypyrrole; Shi et al. prepared hierarchical nanoscale PANI conductive polymers by polymerization method, and showed a higher specific capacitance of 480F / g (0.2A / g) and cycle stability; Zhao et al prepared a biomass-based porous conductive polymer with a specific surface area of ​​207-331m 2 / g, has a specific capacitance of 184F / g at a current density of 0.5A / g, and maintains the original specific capacitance of 74% after 1000 cycles; compared with carbon materials, conductive polymers also have the characteristics of low cost, And can produce a larger specific capacitance; however, compared with carbon materials, conductive polymers as electrode materials face problems such as poor cycle life, which seriously limits their practical applications; at present, the research direction of researchers continues Synthesize new conductive polymers or combine conductive polymers with carbon materials to try to further improve the specific capacitance and cycle stability of the material

[0008] 3. Metal oxides store electrical energy through the pseudocapacitive reaction between the surface of the material and the electrolyte, which is much greater than the electric double layer capacitance of carbon materials, thus becoming a hot spot in capacitor research; the most commonly used capacitor materials for metal oxides are RuO 2 and IrO 2 and other noble metal oxides, which have high specific capacitance, good conductivity and stability; however, the limited resources of noble metals and high preparation costs limit their practical applications; therefore, transition metal oxides with high cost performance have caused have attracted widespread attention, such as tin oxide, iron oxide, manganese dioxide, nickel oxide, cobalt oxide, etc.; they are low in material cost, environmentally friendly, and can produce high specific capacitance in both alkaline and neutral electrolytes, but Compared with carbon materials and noble metal oxides, their cycle stability needs to be improved; at present, how to improve its conductivity, cycle stability, and further improve its specific capacitance is the main focus of researchers; Combining with other transition metal oxides or carbon materials has been proved to be an effective way to improve the comprehensive electrochemical performance of metal oxides, and has caused extensive research;

[0009] 4. As an emerging electrode material, transition metal sulfide has attracted extensive attention from relevant researchers due to its special physical and chemical properties; metal sulfide can not only provide relatively higher conductivity than metal oxides, but also its Abundant redox reactions also contribute to the acquisition of high specific capacitance. In addition, they have higher thermal stability compared to conductive polymers. The combination of the above factors makes transition metal sulfides have great potential to become more practical Electrode materials; at present, such as: nickel sulfide, cobalt sulfide, zinc sulfide, copper sulfide, molybdenum sulfide and other nanostructured transition metal sulfides have been successfully synthesized and widely used in supercapacitors and related electrochemical research; although metal Sulfide has a series of advantages, but compared with the good conductivity of carbon materials, it still has relatively poor conductivity, low ionic conductivity, and it is prone to agglomeration during the preparation process, resulting in reduced utilization , so that the specific capacitance cannot reach the theoretical value; at the same time, since sulfide is used as an electrode material in the process of charging and discharging, redox reactions will inevitably occur, and irreversible reactions will inevitably occur in this process, which will lead to structural changes. As a result, the capacitive properties of the material are difficult to maintain a stable state, greatly reducing the service life of the material; due to the above shortcomings, the wide application of pseudocapacitive materials in practice has been affected, so how to further improve the performance of pseudocapacitive materials such as sulfides The conductivity and cycle stability have become the focus of research; transition metal sulfides occupy an important position in active materials because of their good charge storage capacity, and have broad applications in energy storage and conversion, catalysis, and electronic devices. Application prospects; In 2004, graphene was discovered by Novoselov and Geim of the University of Manchester, and thus won the Nobel Prize in Physics in 2010; at the same time, graphene-like two-dimensional transition metal sulfides have aroused people's attention again and obtained A certain development; transition metal sulfides have many unique physical and chemical properties, and relatively better conductivity and stability than their corresponding metal oxides

Due to the lower electronegativity of sulfur relative to oxygen, the structure of sulfide is more flexible than that of oxides, the structure is less likely to be destroyed, and it is more conducive to the transport of electrons in materials; therefore, it is used in solar energy, optics, The fields of catalysis and batteries have great application potential and have attracted extensive attention; however, the research on the reaction mechanism of transition metal sulfide nanomaterials in the application process is not deep enough and systematic enough, how to successfully realize the controllable synthesis of them, and Applied in catalysis, electrochemical energy storage, and how to improve its application value remains to be studied

[0010] Lei et al. studied the formation of a composite structure by coating polypyrrole between the sheets of copper sulfide microspheres and its surface to improve the specific capacitance and stability of the material, and finally obtained the highest specific capacitance of 427F / g (1A / g), and After 1000 cycles, the capacitance retention rate was 88%; Cheng et al. improved its specific capacitance and stability by loading nano-sized manganese sulfide nanoparticles on nitrogen-doped graphene nanosheets, and finally obtained the highest specific capacitance of 933.6F / g (1A / g), and after 2000 cycles, the capacitance retention rate is 95%, and the specific capacitance and stability have been greatly improved, but when the power density is 800W / kg, the energy density is 27.7 Wh / kg, relative to the energy density required for practical applications, it still needs to be improved; at present, copper and manganese sulfide are still facing some problems, such as the improvement of stability, the increase of specific capacitance, and the improvement of energy density.

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