Preparation, structure, and electrochemical performance of anodes from artificial graphite scrap for lithium ion batteries

Abstract

Artificial graphite scrap prepared from petroleum coke with low degree of graphitization was further graphitized under various conditions. Different categories of coke were also treated with the optimum technology. The prepared samples were characterized with X-ray diffraction, ash content determination, morphology observation, and galvanostatic charge and discharge. It was shown in the experiments that the heat treatment temperature should be increased to 2800 °C to remove impurities. Slow heating rate and evacuation technology were beneficial to the growth of graphite crystallite and the improvement of discharge capacity. And the latter condition possessed the larger influences, especially on the growth of crystallite dimension in the b axis direction, degree of graphitization, and discharge capacity. The sample D-3000 prepared from pure needle coke possessed the maximum discharge capacity of 342.1 mAhg⁻¹ among all prepared samples. The linear regression equations between the volume of graphite crystallite and discharge capacity were established.