Sulfuryl electrolyte for high-energy-density and high-safety lithium ion battery and preparation method of Sulfuryl electrolyte

Abstract

The invention discloses a sulfuryl electrolyte for a high-energy-density and high-safety lithium ion battery and a preparation method of the sulfuryl electrolyte, and belongs to the technical field oflithium ion batteries. Conductive lithium salt is added into common electrolyte to prepare the sulfuryl electrolyte, the concentration of the conductive lithium salt is 1.5-2.5 times that of the common electrolyte, the common electrolyte comprises sulfone solvents, linear carbonic ester solvents and the conductive lithium salt, and the conductive lithium salt is fluorine-containing lithium salt.According to the sulfuryl electrolyte, the circulation performance of the sulfuryl electrolyte is improved by the aid of high-concentration lithium salt, a graphite negative electrode surface film isoptimized in the discharging process under the condition of the high-concentration lithium salt, surface activity of an electrode is restrained, so that further contact between the electrolyte and anactive substance of the electrode is restrained, reductive decomposition of sulfone solvents of the electrolyte on the surface of the electrode is decreased, circulation stability of the lithium ion batteries under the sulfuryl electrolyte is improved, and safety, service life, energy density and specific discharge capacity are improved.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, and in particular relates to a sulfone-based electrolyte for high-energy-density and high-safety lithium-ion batteries and a preparation method thereof. Background technique [0002] Among commercial secondary batteries, lithium-ion batteries have the highest specific energy and the best cycle performance, and because of the diversity of electrode materials, they have broad development prospects as energy storage batteries. However, with the advancement of technology and the continuous development of the market, the demand for battery energy density is becoming increasingly urgent. Therefore, improving the energy density of lithium batteries has become another new topic that plagues scientific researchers. [0003] At present, the positive electrode materials of commercial lithium-ion batteries mainly include lithium manganese oxide, lithium cobalt oxide, lithium iron phosphate, etc. These ba...

AI Technical Summary

Problems solved by technology

Therefore, another way to increase the energy density of the battery is to find an electrolyte that can match the high-voltage operation. You can add high-voltage resistant additives to the carbonate electrolyte to achieve the goal, but this method treats the symptoms but not the root cause, and the sulfone-based electrolyte First reported in 1985, sulfones have a high oxidation potential due to their strong electron-withdrawing groups [more than 5.0V (vs. Li / Li + )], its wide electrochemical window becomes wider as the oligomer chain shortens, it is an ideal high-pressure solvent, and the use of sulfone-based electrolytes can fundamentally solve the problem of high-voltage instability

Unfortunately, the most common disadvantage of sulfones is their incompatibility with graphite electrodes, resulting in a large amount of irreversible capacity

Sulfolane-based electrolytes cannot effectively passivate graphite electrodes despite using EMC as a co-solvent

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