Pseudo high-concentration ester lithium-sulfur battery electrolyte and lithium-sulfur battery

Abstract

The invention discloses a pseudo high-concentration ester lithium-sulfur battery electrolyte and a lithium-sulfur battery. The electrolyte contains lithium salt, an ester solvent and a non-solvent solution, the concentration of the lithium salt in the ester solvent is higher than 3.0 mol / L, and the overall concentration of the lithium salt in the pseudo high-concentration electrolyte is not lower than 0.5 mol / L. According to the battery electrode provided by the invention, the problems such as high viscosity and low conductivity of the lithium-sulfur battery electrolyte containing the high-concentration lithium salt can be improved, the electrolyte has incombustibility, and the electrochemical performance and safety of the lithium-sulfur battery can be obviously improved.

Description

technical field [0001] The invention relates to a pseudo-high-concentration lithium-sulfur battery electrolyte and a corresponding lithium-sulfur battery, in particular to a lithium-sulfur battery electrolyte containing a high-concentration lithium salt of a fluoroether. Background technique [0002] The theoretical specific capacity of the lithium-sulfur battery is 1675mAh / g, and the theoretical specific energy is 2600Wh / Kg, much higher than the existing lithium-ion batteries. Moreover, sulfur reserves are abundant, the price is low, low toxicity and no pollution. Therefore, lithium-sulfur batteries have become candidates for next-generation high-energy lithium batteries and have attracted worldwide attention. Lithium polysulfide, an intermediate product of lithium-sulfur batteries, will directly react with esters. Lithium-sulfur batteries generally use ethers as electrolyte solvents, rather than carbonates and carboxylates used in lithium-ion battery electrolytes. The so...

AI Technical Summary

Problems solved by technology

However, most of the solvent molecules in high-concentration lithium-salt electrolytes participate in the solvation of lithium ions and there are few free solvent molecules. The main problems of high-concentration lithium-sulfur battery electrolytes are high viscosity and low conductivity.

High viscosity is not conducive to the migration of lithium ions and the full contact between the electrolyte and the electrode, and the corresponding lithium-sulfur battery has a high impedance value

Low conductivity indicates that the migration rate of lithium ions in the electrolyte is slow, which is not conducive to the rate performance and low temperature performance of the battery

Therefore, finding new ways to solve the problems of high viscosity and low conductivity of high-concentration lithium-sulfur battery electrolytes is an important way to promote the practical application of high-concentration lithium-sulfur battery electrolytes and accelerate the commercialization of lithium-sulfur batteries.

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