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

Abstract

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.