Comprehensive test method of content of impurities in lithium ion battery nano conductive agent

Abstract

The invention belongs to the field of test of lithium battery electrode impurities and particularly relates to a comprehensive test method of content of impurities in a lithium ion battery nano conductive agent. The method comprises the following steps: (1) burning at high temperature to remove graphite; (2) testing and analyzing elements components of impurities in residue via an SEM-EDS energy spectrum; (3) carrying out specific acid digestion treatment by using different type of acid solutions according to the elements components of the impurities tested by the SEM-EDS energy spectrum; (4) filtering a digestion solution after carrying out acid digestion in the step (3) and titrating constant by using ultrapure water to carry out ICP test; (5) carrying out the steps (1)-(2) repeatedly if residue still exists after carrying out acid digestion in the step (4) so as to carry out semi-quantitative SEM-EDS energy spectrum analysis test on the residue subjected to acid digestion; (6) calculating the total content of the impurities, namely determining the total content of the impurities as the content of ICP if no residue exists in the step (4), and determining the total content of the impurities as the sum of the content of ICP and the content tested by the SEM-EDS if the residue exists in the step (4).

Description

technical field [0001] The invention belongs to the field of lithium battery electrode impurity testing, and in particular relates to a comprehensive testing method for the impurity content of a lithium-ion battery nano-conductive agent. Background technique [0002] Most of the positive electrode materials of lithium-ion batteries are semiconductors or even insulators, which have poor conductivity. Conductive agents must be added to improve their conductivity. Although the negative electrode materials have slightly better conductivity, conductive agents also need to be added to maintain their structural stability during cycling. . The widespread use of conductive agents has also become one of the sources of impurities in lithium-ion batteries. Therefore, it is especially important to accurately test the impurity content in the conductive agent for lithium-ion batteries. [0003] The impurities in the conductive agent are different because of the different preparation proc...

AI Technical Summary

Problems solved by technology

This method is suitable for granular conductive agents. Due to the special multi-dimensional channel shapes and different preparation processes of tubular and fibrous conductive agents, especially the conductive agent slurry is hard and blocky after drying, and it is difficult to be crushed into powder. It is difficult to dissolve the impurities, which leads to small test results, and it is difficult to accurately test the impurity content, which in turn increases the high-impurity conductive agent into the finished battery, increasing battery self-discharge and safety risks. From an economic point of view, the impurity caused by unqualified Bad batteries cause waste of raw materials and costs

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