Silicon dioxide-based metal sulfide composite material as well as preparation method and application thereof

Abstract

The invention discloses a silicon dioxide-based metal sulfide composite material prepared by a two-step hydrothermal method, concretely, growing a nano flower-like structure of manganese disulfide andcobalt disulfide on the outer surface of template agent silicon dioxide by adopting a two-step hydrothermal method, and etching the silicon dioxide by hydroxyl through vulcanization reaction. Thus, part of silicon dioxide is released from hydrolysis of sulfide ions, a certain hole is etched in an internal silicon dioxide template, ion migration is facilitated, and the layered nano metal sulfide composite material based on silicon dioxide can be prepared. The preparation method comprises the following steps: 1, preparing a composite metal oxide precursor; and 2, preparing the silicon dioxide-based metal sulfide composite material. When the material is used as a supercapacitor electrode material, the material is charged / discharged within the range of 0-0.55 V, and when the discharge currentdensity is 1 A / g, the specific capacitance is 1150-1160 F / g. The material has excellent material stability and excellent ion transmission capability.

Description

technical field [0001] The invention relates to the technical field of supercapacitors, in particular to the preparation of a silicon dioxide-based metal sulfide composite material and its application in the field of supercapacitors. Background technique [0002] With economic growth, people's demand for energy is also increasing rapidly. Although human beings can obtain their needs from traditional fossil energy sources, they inevitably cause greenhouse effect and pollution. In the past few decades, renewable energy such as wind energy, solar energy, and tidal energy have flourished and are considered to be an effective way to solve the energy crisis. However, these energies need to be stored in highly efficient devices such as lithium-ion batteries or supercapacitors. Currently, among various energy storage devices, supercapacitors are at the forefront of this research. As one of the representative modern energy storage devices, supercapacitors have become a research ho...

AI Technical Summary

Problems solved by technology

Manganese silicate showed a capacitance of 517 F / g at a current density of 0.5 A / g, but after 3600 electrochemical cycles, only 34% of the initial capacitance could be retained, the decrease in specific capacitance may be attributed to the crystal structure Expansion and contraction, which lead to the destruction of the hollow spherical structure and the tiny lamellar / bubble-like structure, resulting in a reduction in the charge storage capacity of the manganese silicate during charging

Therefore, the literature hoped that by using manganese silicate as the positive electrode in polyvinyl alcohol-potassium hydroxide gel electrolyte, and using activated carbon as the negative electrode material, a high-capacity performance, flexible asymmetric solid-state supercapacitor was assembled to improve the material stability, however, it was obtained that the combined device exhibited a capacitance retention of 32% after 900 electrochemical cycles

This unsatisfactory cycle stability is due to the decrease in conductivity of manganese silicate during prolonged charge / discharge, leading to the decomposition of manganese silicate

[0007] This technology still has the following two problems: after introducing the silica template, the porous hollow sphere structure is easily broken; in trying to solve the problem of electrode material cycle stability, it still fails to take into account the specific capacitance performance and electrical conductivity. Chemical stability seriously affects its application value as an electrode material

After analysis by the inventors, it was found that from the microscopic appearance in this document, the agglomeration phenomenon of metal sulfides is serious, which seriously affects the transmission of electrons and limits the improvement of electrochemical performance.

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