A kind of composite material based on silica metal sulfide and its preparation method and application

Abstract

The invention discloses a silica-based metal sulfide composite material, which uses a two-step hydrothermal method to grow a nano-flower structure of manganese disulfide and cobalt disulfide on the outer surface of the template agent silica, and at the same time through the vulcanization reaction, Silicon dioxide is etched by hydroxide, so that part of the silicon dioxide is released from the hydrolysis of sulfide ions, and the internal silicon dioxide template is etched into certain holes to facilitate ion migration to obtain a silicon dioxide-based layered nanometal sulfide composites. The preparation method comprises the following steps: 1. preparation of composite metal oxide precursor; 2. preparation of silicon dioxide-based metal sulfide composite material. As an electrode material for supercapacitors, it is charged / discharged in the range of 0‑0.55 V, and the specific capacitance is 1150‑1160 F / g when the discharge current density is 1 A / g. It has excellent material stability and excellent ion transmission ability.

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 the growth of the economy, people's demand for energy is also increasing rapidly. Although humans can obtain demand from traditional fossil energy sources, they inevitably cause the greenhouse effect and pollution. Renewable energy sources such as wind, solar, and tidal energy have flourished in the past few decades and are considered to be an effective way to solve the energy crisis. However, these energy sources need to be stored in 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 hotspot...

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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