Titanium dioxide-coated lithium-sulfur battery positive electrode material and preparation method thereof

Abstract

The invention discloses a titanium dioxide-coated lithium sulphur battery anode material and a preparation method thereof, used for solving the technical problem that an existing lithium sulphur battery anode material is low in specific discharge capacity. The technical scheme is that the anode material is prepared from sulphur, a carbon fiber sheet and a titanium dioxide casing. The preparation method comprises the steps of adsorbing a gas sulfur elementary substance by adopting the carbon fiber sheet, then using titanium dioxide to coat a mixture of the carbon fiber sheet and the sulfur elementary substance by adopting a titanium tetrachloride hydrolysis method, drying, cleaning, and drying again to obtain the titanium dioxide-coated lithium sulphur battery anode material. As elementary substance sulfur particles evenly cover the surface of the carbon fiber sheet and are externally coated by TiO2 evenly, the strong adsorption fixing capacity of the microcosmic structure of the carbon fiber sheet and the TiO2 to a polysulfide buffers volume change before and after sulfur lithiation and can limit the polysulfide generated in the charging and discharging processes of a lithium sulphur battery in a TiO2 nanotube, so that the specific discharge capacity and the cycling stability of the lithium sulphur battery are remarkably improved.

Description

technical field [0001] The invention relates to a lithium-sulfur battery cathode material, in particular to a titanium dioxide-coated lithium-sulfur battery cathode material. It also relates to a preparation method of the titanium dioxide-coated lithium-sulfur battery cathode material. Background technique [0002] Among many secondary batteries, traditional lithium-sulfur secondary batteries use metal lithium (theoretical specific capacity 3861mAh g -1 ) as the negative electrode, elemental sulfur (theoretical specific capacity 1675mAh g -1 ) as the positive electrode, the theoretical energy density is as high as 2600Wh·kg -1 , is currently known as the lithium secondary battery system with the highest energy density except for lithium-air batteries; at the same time, lithium-sulfur batteries also have the advantages of abundant sulfur cathode materials, low cost and environmental friendliness, and are considered to be the most developed at present. One of the secondary ...

AI Technical Summary

Problems solved by technology

Although the above method is simple, there are mainly the following problems: elemental sulfur is an electronic and ion insulator at room temperature, has extremely low electronic conductivity, and the polysulfides produced during the charging and discharging process of the battery are easily soluble in the electrolyte, resulting in " Shuttle effect”, resulting in a large amount of irreversible loss of positive active material, reducing the capacity of the battery

However, TiO 2 There are some problems in the conductivity, resulting in a certain bottleneck in the improvement of battery performance

In summary, although the above methods can improve the electrochemical performance of lithium-sulfur batteries to a certain extent, their electrochemical performance such as specific discharge capacity and cycle stability is still far from commercialization and needs to be improved.

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