Facile synthesis of MOF-derived hollow NiO microspheres integrated with graphene foam for improved lithium-storage properties

Abstract

In this work, Ni-based metal-organic framework (MOF) hollow microspheres were firstly grown on the substrate of graphene foam (GF) by a facile solvothermal method, and then the NiO/GF composites were obtained after the calcination of Ni-MOF/GF precursors. The resulting NiO/GF could be employed as free-standing anode electrodes of lithium-ion batteries, showing superior specific capacities and cycling stabilities to pure NiO and GF. In detail, the optimized composite exhibited a capacity of 640 mAh g−1 after 50 cycles at 100 mA g−1. Even at a high current of 1 A g−1, the capacity still reached to ∼330 mAh g−1. The excellent electrochemical performance can be attributed to the synergistic effect between NiO and GF components. The GF matrix not only improves the conductivity of electrode, but also provides a flexible platform for the loading of active materials, preventing the escape and diffusion of NiO particles into the electrolyte during the cycling. Meanwhile, the well-defined hierarchical hollow structure of NiO in the composite effectively mitigates the volume change of metal oxides during the insertion/extraction reaction.