Preparation method of hollow graphene ball/sulfur composite material

Abstract

The invention discloses a preparation method of a hollow graphene ball / sulfur composite material and belongs to the technical field of chemical batteries. The preparation method comprises the following steps: an ethanol solution of tetraethyl orthosilicate is mixed with and reacts with the ethanol solution of ammonia water and the ammonia water, so as to obtain silica nanospheres; silica nanospheres and cetyltrimethylammonium bromide are dispersed in deionized water; an aqueous solution of graphene oxide is added; a mixture is centrifuged after stirring and reaction; a solid phase is taken to be washed, dried and placed in a vacuum tube furnace for reduction at a high temperature; an HF aqueous solution is added to perform corrosion reaction, so as to obtain the hollow graphene ball; finally, the hollow graphene ball and sulfur are mixed and subjected to the thermal melting and sulfur volatilization reaction so as to obtain the hollow graphene / sulfur composite material. The preparation method provided by the invention is low in production cost; the prepared product is favorable for forming a conductive network and improving the conductivity.

Description

technical field [0001] The invention belongs to the technical field of chemical batteries, and in particular relates to a method for preparing a hollow graphene sphere / sulfur composite material which can be used as a lithium-sulfur cathode material. Background technique [0002] Energy is one of the basic elements to maintain social development. Before the industrial revolution, the need for energy was not so urgent. After the industrial revolution, the demand for energy became more and more serious. Nowadays, with the development of human society and productivity, the energy problem has become a world-wide primary problem, and it has also aroused extensive attention of governments and scientific researchers in various countries. To deal with energy problems, the current solutions are roughly divided into three categories. One is to develop and utilize new available energy sources, such as solar energy, wind energy, and geothermal energy. The second is to reduce energy us...

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Problems solved by technology

However, during the discharge process of lithium-sulfur batteries, elemental sulfur is reduced to S -2 There will be multiple intermediate states generated during the process, where Li 2 Sn (4≤n≤8) is easily soluble in the organic electrolyte, diffuses from the positive electrode to the negative electrode, and eventually generates Li at the negative electrode as the discharge progresses 2 S is deposited, while Li 2 S is insoluble in organic electrolyte, which causes problems such as poor cycle performance, low Coulombic efficiency, and high self-discharge rate of lithium-sulfur batteries, which delays the pace of its practical application.

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