Process for determining hydrogen fluoride in lithium ion cell electrolyte

A technology of lithium-ion battery and measurement method, which is applied in the field of determination of hydrogen fluoride concentration, can solve the problems of high price of titrant tetrabutylammonium hydroxide, high cost of test method, high measurement result, etc., so as to achieve less consumption of samples and reagents , accuracy guarantee, and the effect of easy method

Inactive Publication Date: 2005-06-29
OCEAN UNIV OF CHINA +2
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Problems solved by technology

In the currently disclosed hydrogen fluoride determination technology, Merck uses tetrabutylammonium hydroxide as titrant and bromothymol blue as indicator, and performs titration analysis in anhydrous methanol. This method is due to the titrant tetrabutylammonium hydroxide There is a systematic error due to the side reaction between butylammonium and methanol solvent, which makes the measurement result higher; in addition, the titrant tetrabutylammonium hydroxide is expensive, which leads to the high cost of the test method
On this basis, Shenzhen BYD Company has published a non-aqueous titration method for hydrogen fluoride in the electrolyte of lithium-ion batteries. This method uses bromothymol blue as an indicator, dilutes the electrolyte in an anhydrous organic solvent, and dilutes the electrolyte with sodium methoxide. As a titrant, use the naked eye to titrate until the solution turns from yellow to blue. This method is complicated to operate and needs to be operated in a glove box. It is mainly suitable for lithium-ion battery electrolytes with medium and high HF concentrations. It is suitable for testing HF content below 20ppm Lithium-ion battery electrolyte has certain defects

Method used

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Embodiment Construction

[0022] The specific instructions of this Act are as follows:

[0023] 1. Principle

[0024] Add a standard solution of a certain mass and concentration to a sample of known volume, and calculate the concentration of the ion to be measured in the test solution according to the change in potential before and after the addition. Let the mass of the test solution be m x , with a concentration of C x (for mass molar concentration), then its potential is:

[0025] E. x =φ′+S*lg C x (1)

[0026] Where S is the efficiency of the corresponding curve. Add m to the test solution s g concentration is C s The standard solution, because the acidity will decrease after the standard sample is added, the potential is:

[0027] E. sx =φ′+S*lg[(C x *m x -C s *m s ) / (m x +m s )] (2)

[0028] So: ΔE=E x -E sx =S*lg[(m x +m s )C x / (C x *m x -C s *m s )] (3)

[0029] Solved: C x =...

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Abstract

This invention discloses a lithium ion battery hydrofluoric content test method in the electrolyte, which uses alcoholate and alkali metals as standard solution and is characterized by the following: to choose certain electrolyte with HF to be measured to test its electrolyte potential; to join the above quantity of the known concentration to the electrolyte to be measured to test the electrolyte potential after the joining; to compute the density of the HF in the electrolyte according to the relative data.

Description

technical field [0001] The invention relates to a method for measuring the concentration of hydrogen fluoride in an electrolyte solution of a lithium ion battery. Background technique [0002] Lithium-ion battery electrolyte is an electrolyte lithium salt such as: LiPF 6 , LiClO 4 , LiAsF 6 , LiBF 4 , LiCF 3 SO 3 , LiN(SO 2 CF 3 ) 2 , LiPF 4 (CF 3 ) 2 Soluble in aprotic solvents, such as propylene carbonate (PC), ethylene carbonate (EC), ethylene glycol dimethyl ether (DME), dimethyl carbonate (DMC), tetrahydrofuran (THF), etc. In practical applications, people usually choose LiPF for the consideration of comprehensive factors such as the safe use of electrolyte, environmental protection and battery performance. 6 As a lithium salt, ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and the like are used as solvents to form a multiple electrolyte system. Due to LiPF 6 The nature of LiPF is unstable and easy to hydrolyze. If there ar...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N27/413G01N31/16
Inventor 曹晓燕薛泰安熊俊威冯超
Owner OCEAN UNIV OF CHINA
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