Mesoporous NiCo2O4 nanoneedles grown on three dimensional graphene networks as binder-free electrode for high-performance lithium-ion batteries and supercapacitors

Mesoporous nickel cobaltite (NiCo2O4) nanoneedles grown on three dimensional graphene networks have been successfully prepared by a facile solvothermal reaction with subsequent annealing treatment. The NiCo2O4/3DGN hybrid is then used as binder-free electrode for high-performance lithium-ion batteries and supercapacitors. The three dimensional graphene based binder-free electrode is considered more desirable than powder nanostructures in terms of shorter Li+ ion diffusion and electron transportation paths, good strain accommodation, better interfacial/chemical distributions and high electrical conductivity. As a result, when used as an anode material for lithium-ion batteries (LIBs), it exhibits high specific discharge capacity as well as superior cycling stability up to 2000 cycles. When it is used for supercapacitor application, this hybrid delivers a high specific capacitance of 970 F g(-1) at a high current density of 20 A g(-1) with excellent capacitance retention of similar to 96.5% after 3000 cycles. Moreover, this synthesis strategy is simple and effective, which could be extended to the construction of other three dimensional graphene based metal oxides hybrid for energy applications. (C) 2015 Elsevier Ltd. All rights reserved.