Coupling of two-dimensional MXenes and graphene for boosting the hydrogen storage performance of MgH2.

MgH2 used in solid-state hydrogen storage still suffers from high thermal stability and slow hydrogen absorption-desorption kinetics. Here, we report a hybrid of MgH2-Ti3C2/graphene prepared through a facile wet chemical method followed by a ball-milling method. It was confirmed that the coupling of Ti3C2 and graphene possesses a synergistic effect on the hydrogen desorption and absorption reactions of MgH2/Mg. The initial temperature of MgH2-Ti3C2/graphene to desorb hydrogen was reduced to 169 °C significantly and it could desorb 6.8 wt% H2 within 6 min at a constant temperature of 300 °C. Moreover, the desorbed sample could start to absorb hydrogen at room temperature and achieve a capacity of 6.0 wt% when the temperature was gradually increased to 350 °C. These results are far superior to pristine MgH2, disclosing that the addition of two-dimensional Ti3C2/graphene is an efficient strategy to boost the hydrogen storage performance of MgH2.