Process for refining biphenol used for electrolyte of Lithium-ion battery

Abstract

A process for refining the biphenol used for electrolyte of Li-ion battery includes dissolving the industrial biphenol in organic inertial solvent, adding sulfuric acid, reaction on impurities, separation, deacidifying, evaporating for crystallizing, vacuum rectifying, adding Li flakes and vacuum rectifying. Its advantages include high purity (more than 99.5%), low harmful impurities content (less than 100 ppm), and high over-charge resistance of Li-ion battery.

Description

technical field [0001] The invention relates to the technical field of manufacturing lithium ion batteries, in particular to a method for refining additives for non-aqueous electrolytes. Background technique [0002] In the manufacturing process of lithium-ion batteries, adding an appropriate amount of biphenyl to the non-aqueous organic solvent electrolyte can improve the safety of the battery during use. However, ordinary industrial products or chemical reagents, such as cascade biphenyl, contain more impurities harmful to batteries such as thiophene, phenylthiophene, and mercaptobiphenyl, etc., when added to the non-aqueous electrolyte composed of lithium hexafluorophosphate and organic carbonate Finally, the impurities in the biphenyl polymerize under the trigger of a small amount of fluoride ions in the electrolyte, the electrolyte turns red, and the conductivity drops sharply, thus affecting the performance of the battery. Contents of th...

AI Technical Summary

Problems solved by technology

However, ordinary industrial products or chemical reagents, such as cascade biphenyl, contain more impurities harmful to batteries such as thiophene, phenylthiophene, and mercaptobiphenyl, etc., when added to the non-aqueous electrolyte composed of lithium hexafluorophosphate and organic carbonate Finally, the impurities in the biphenyl polymerize under the trigger of a small amount of fluoride ions in the electrolyte, the electrolyte turns red, and the conductivity drops sharply, thus affecting the performance of the battery.