Additive-free sulfonated graphene/sulfur electrode slice and preparation method and application thereof

Abstract

The invention belongs to the technical field of lithium sulfur batteries and particularly relates to an additive-free sulfonated graphene / sulfur electrode slice and a preparation method and application thereof. The preparation method comprises the following steps: firstly, modifying graphene oxide to obtain sulfonated graphene with good water solubility and electrical conductivity; dispersing the sulfonated graphene in a sodium thiosulfate solution, adding a sulfuric acid solution and forming a sulfonated graphene / sulfur compound through a disproportionation reaction; carrying out size mixing on the compound through taking absolute ethyl alcohol as a solvent and coating a carbon-coated aluminum foil with the size to obtain the electrode slice which is applied to positive electrodes of the lithium sulfur batteries. The preparation method disclosed by the invention is simple in process and good in reproducibility; the raw material has excellent electrical conductivity and a certain viscosity, so that conductive carbon black and binder are not needed in the manufacturing of the electrode slice and the volume energy density of the positive electrode materials of the lithium sulfur batteries can be greatly increased; in addition, generated intermediate products can be prevented from being diffused into electrolyte, so that the shuttle effect is reduced, and the cycle performance and the rate performance of the lithium sulfur batteries are increased.

Description

technical field [0001] The invention belongs to the technical field of lithium-sulfur batteries, and in particular relates to a sulfonated graphene / sulfur electrode sheet and a preparation method and application thereof. Background technique [0002] Lithium-sulfur battery, using elemental sulfur (or sulfur-containing compound) as the positive electrode, metal lithium as the negative electrode, a type of metal lithium secondary battery that realizes the mutual conversion between chemical energy and electrical energy through the chemical reaction between sulfur and lithium, its theoretical ratio Capacity is 1675 mAh g -1 , the theoretical energy density is 2600 Wh kg -1 , the actual energy density can reach 300 Wh kg -1 , it is very likely to increase to 600 Wh kg in the next few years -1 About, compared with traditional lithium ion battery oxide electrode materials, such as lithium cobalt oxide, lithium manganese oxide, and lithium iron phosphate, sulfur-based cathode mat...

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Problems solved by technology

Zhang et al. used the chemisorption of a large number of oxygen-containing groups on the surface of graphene oxide (GO) to the intermediate product to achieve the immobilization of sulfur, but the large number of oxygen-containing groups on the surface of GO destroyed the conjugated structure of graphene itself, reducing Electronic conductivity [L.W. Ji, M.M. Rao, H.M. Zheng, L. Zhang, Y.G. Zhang, J. Am. Chem. Soc. 2011, 133 (46), 18522]

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