Conversion of Coal into Graphitized Microcrystalline Carbon with a Hierarchical Porous Structure for Electrochemical Hydrogen Storage

Electrochemical hydrogen storage, which can be performed at ambient temperatures and mild pressures, is regarded as a promising technique to store hydrogen safely and efficiently. In this study, the electrochemical hydrogen storage performance of activated carbon was improved by synthesizing a graphitized microcrystalline porous carbon material through a facile one-step catalytic carbonization activation procedure using coal as the raw material. Owing to the synthetic effect of the conductive network and the hierarchical porous structure, the carbon electrode exhibited high capacity, excellent rate performance, and substantial cycling stability for electrochemical hydrogen storage. The hydrogen storage capacity of the material was 278 mA h g(-1) at a current density of 100 mA g(-1), with considerable capacity retention of 86% after 50 cycles. The electrode exhibited superior rate capacity of 260 mA h g(-1) at 200 mA g(-1). Porous carbon with microcrystalline graphite was demonstrated to be an efficient electrode for electrochemical hydrogen storage.