In situ synthesis of mesoporous NiMoO₄ on ball milled graphene for high performance supercapacitors

Hydrothermal method is used to in situ synthesize mesoporous graphene@NiMoO₄ nanocomposites as supercapacitor electrodes. NiMoO₄ nanorods are formed on fresh graphene surface, while scattered NiMoO₄ nanoparticles are obtained on the surface of ball milled graphene. graphene@NiMoO₄ nanocomposites electrodes exhibit a higher electrochemical performance compared with a pure NiMoO₄ electrode, and the ball milled graphene@NiMoO₄ electrodes have the maximum specific capacitance of 2100 F g^-1 at 1 A g^-1 discharge current and maintains at least 92% of its initial capacitance after 5000 operational cycles. Such an enhanced supercapacitive performance originates from the mesoporous structure, more electroactive sites, large specific surface area, high electrical conductivity and synergistic effect between NiMoO₄ and the graphene.