Lithium-sulfur battery electrolyte and lithium-sulfur battery

Abstract

The invention relates to a lithium-sulfur battery electrolyte. The lithium-sulfur battery electrolyte comprises lithium salt and an organic solvent, wherein the lithium salt comprises a lithium sulfate derivative shown in a general formula (1) and other lithium salt, and the general formula (1) is shown in the specification; the other lithium salts are one or more of lithium bis (trifluoromethanesulfonimide) (LiTFSI), lithium perchlorate, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perfluoroalkylsulfonate and lithium perfluoroalkylsulfonate methyl; and the molar mass ratioof the lithium sulfate derivative shown in the general formula (1) to the other lithium salt is 1: (0.3-6). According to the lithium-sulfur battery electrolyte, the initial capacity of a lithium-sulfur battery is improved and the cycle life of the lithium-sulfur battery is prolonged by improving the components of the electrolyte.

Description

technical field [0001] The invention belongs to the field of battery electrolyte materials, and in particular relates to a lithium-sulfur battery electrolyte and a lithium-sulfur battery. Background technique [0002] A lithium-sulfur battery is a type of lithium battery in which elemental sulfur or sulfur-containing materials are used as the positive electrode of the battery, and metallic lithium is used as the negative electrode. According to the amount of electricity that can be provided by the complete reduction of elemental sulfur per unit mass to lithium sulfide, the theoretical discharge capacity of lithium-sulfur batteries can be calculated to be 1675mAh / g, and the theoretical energy density is 2567Wh / Kg. Compared with traditional lithium-ion batteries, lithium Sulfur batteries have great advantages and are expected to replace conventional lithium-ion batteries as secondary batteries with high energy density and long life in the future. [0003] However, there are s...

AI Technical Summary

Problems solved by technology

However, despite accounting for 90% of the total battery mass, the organic solvent of the traditional lithium-sulfur electrolyte only maintains lithium ion transport, but does not play a substantial role in further improving the capacity of lithium-sulfur batteries.

At the same time, in the cycle process of lithium-sulfur batteries with traditional electrolytes, soluble polysulfides "shuttle" between the positive and negative electrodes, so the basic problem of poor long-term cycle of lithium-sulfur batteries cannot be well solved.

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