Characterization of coating on graphite anode material for lithium-ion batteries

Abstract

To improve the performance of lithium-ion batteries, the graphite anode can be treated with special coating. Thus the charge transfer resistance through the material can be lowered and thereby enable e.g. faster charging. The amount of coating is essential the improve the performance. The thesis is investigating thermogravimetric and electrochemical impedance spectroscopy as a method to identify an optimal relation between the amount of coating and the charge transfer resistance. There is found that lower material resistivity gives a higher weight loss where it is assumed that the coating is oxidising, methods for both a relative difference in the weight loss and direct measurement of the weight loss was develop. There was fund a connection between the charge transfer resistance and the resistivity as well. There were too few samples to conclude which method works best or make a firm conclusion of the methods. To further improve the developed methods, there should be more standardised tests with wider varieties of samples in each category. A more developed method should also be used to check if the result is correct.