Effect of co-doping graphene and anthracite on hydrogen storage of Mg/MgH2

Abstract

Carbon materials have been proven to have a favorable impact on the amelioration of the comprehensive characteristics of MgH2 hydrogen storage. Herein, A graphene and anthracite co-doping magnesium (hereafter referred to as Mg–C–G) composite was produced using mechanical ball milling to evaluate the influence of co-doping various types of carbon on the hydrogen storage of Mg/MgH2. It is demonstrated that the co-doping of graphene and anthracite markedly lowered the dehydrogenation peak temperature of MgH2 and optimized its desorption kinetics. The apparent activation energy of the Mg–C–G composite for hydrogen desorption is 94.2 kJ/mol, less than that of pure magnesium by 18.3 kJ/mol. Furthermore, the Mg–C–G composite still maintained 3.72 wt% of hydrogen storage ability after 20 hydrogen uptake and release cycles, achieving a 90.5 % retention rate of hydrogen capacity. This study reveals the impact of carbon species on Mg/MgH2 hydrogen storage, which is a guideline for the design of novel Mg-carbon hydrogen storage systems.