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

A lithium-ion battery and refining method technology, which is applied in the field of additive refining for non-aqueous electrolytes, can solve the problems of decreased electrical conductivity, reddening of electrolytes, affecting battery performance, etc., and achieves the effect of prolonging tolerance time

Inactive Publication Date: 2002-04-10
TIANJIN CHEM RES & DESIGN INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] In a stoppered glass bottle, add 400g of benzene, then add 350g of industrial biphenyl to dissolve, add 100ml of 98% sulfuric acid, shake fully on the shaker for 30min, let stand, the solution is layered, and separate the organic liquid layer with a separatory funnel , then add 100ml of 98% sulfuric acid to the organic liquid, repeat the above operation 5 times, the organic liquid layer becomes colorless. separation, with 1% Li 2 CO 3 Wash the organic liquid with 1000ml of aqueous solution, and then wash the organic liquid with 500ml of distilled water. After 6 times, the washing water is neutral. The organic liquid layer was separated, removed by evaporation at 80°C and the solvent benzene was recovered. 340 g of crystals were obtained. Rectify in vacuum rectification tower, tower top temperature 160 ℃, vacuum tightness 680mmHg, reflux ratio 3: 1, after distilling 40g product, add metal lithium sheet 5g to tower still, adjust reflux ratio 4: 1, continue refining Di...

Embodiment 2

[0024] In embodiment 1, the concentration of sulfuric acid is changed into 80%, and the number of times of pickling is increased to 8 times, and other is the same as embodiment 1. The obtained product has a main content of 99.65% and a water content of 89ppm. After being added to the non-aqueous electrolyte of lithium hexafluorophosphate, the electrolyte does not change color and the conductivity does not change significantly.

Embodiment 3

[0026] In embodiment 1, the concentration of sulfuric acid is changed to 60%, and the number of times of pickling is increased to 15 times, and other is the same as embodiment 1. The obtained product has a main content of 99.53% and a water content of 86ppm. After being added to the non-aqueous electrolyte of lithium hexafluorophosphate, the electrolyte does not change color and the electrical conductivity does not change significantly.

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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...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C7/04C07C15/14
CPCY02E60/122
Inventor 欧秀芹冯锐程耀丽张宝朋
Owner TIANJIN CHEM RES & DESIGN INST
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