Improvement of the electrochemical performance of spent graphite by asphalt coating

Abstract

Abstract Recycling spent anode graphite from scrapped lithium-ion batteries plays a significant role in utilization of graphite resources and environmental protection. However, regenerated graphite basically shows low coulomb efficiency and poor rate capability, which cannot meet the requirements of being reused as an electrode material. Herein, we put forward an asphalt coating method to improve the electrochemical performance of the spent graphite after impurities removal. The structure and morphology of asphalt-coated purified graphite (AC@PG) are characterized by using XRD, TEM and SEM analysis, the results show that the pyrolysis carbon has successfully coated on the purified graphite. Asphalt coating is demonstrated to improve its surface morphology, which is beneficial to the infiltration of the electrolyte. The electrochemical performance of AC@PG with various asphalt coating amounts is systematically investigated, and the results show that when the asphalt coating amount is 10%, the electrochemical performance of AC@PG can reach the optimal value with an initial capacity of 335.4 mAh/g at a rate of 0.1 C, which are better than that of PG (313.8 mAh/g). Furthermore, rate capability is significantly improved after asphalt coating. This proposed asphalt coating method for spent graphite is facile, effective and economical, which has prospects for the industrial processing of graphite.