A comparison of the electrochemical performance of graphitized coal prepared by high-temperature heating and flash Joule heating as an anode material for lithium and potassium ion batteries

Abstract

Natural graphite, commonly used in energy storage applications such as the battery industry, is marked as a supply-risk material due to the elevated demand and limited resources. The synthetic graphite process is inefficient, so there is a highly required for alternative methods of making graphite as anode material. In this study, we report two efficient methods for catalytic graphitization of coal using high-temperature heating and flash Joule heating (FJH). Using both methods, the structure and morphology characterizations have demonstrated the successful structural conversion of coal from an amorphous structure into a crystalline structure. When the obtained graphitized coal samples via the high-temperature heating method (HTC) and via the FJH method (FHC) were used as anodes for lithium-ion batteries (LIBs) and potassium-ion batteries (PIBs), the HTC and FHC presented outstanding rate capability and remarkable stable cycling performance. The HTC and FHC anodes delivered initial charge capacities of 322.5 and 321.3 mAh·g−1, respectively, at a current density of 0.1C. for LIBs. When used as anodes in PIBs, the HTC and FHC delivered initial charge capacities of 265.4 and 262.2 mAh·g−1 at 0.1C current density. These results make the HTC and FHC promising materials for developing energy storage applications. Therefore, this work exploited the low price of coal and its abundant reserves, combined with the FJH technique, which is an effective method for saving energy and time, to produce high-quality graphitized coal materials, which can make this process green and economically attractive.