A novel NiCo2O4@GO hybrid composite with core-shell structure as high-performance anodes for lithium-ion batteries

Abstract

In this study, a unique core-shell structural composite with graphene oxide nanosheets wrapping the hierarchical porous NiCo2O4 microspheres (NiCo2O4@GO) has been successfully prepared by a facile electrostatic assembly process between positively charged hierarchical porous NiCo2O4 microspheres and negatively charged graphene oxide (GO). When used as an anode for lithium-ion batteries (LIBs), the core-shell structured NiCo2O4@GO can not only suppress the aggregation and large volume change of NiCo2O4 microspheres, but also provide faster kinetics for both electrons and lithium ions during charge-discharge process. Moreover, NiCo2O4 microspheres wrapped with GO can restrict the decomposition of the electrolyte and yielding a stable solid electrolyte interphase (SEI) layer during cycling. Due to these merits, the core shell structured NiCo2O4@GO hybrid composite demonstrated a high initial reversible capacity of 1046.6 mAh g−1 at a current density of 50 mA g−1 with capacity retention of 77.6% after 100 cycles, the hybrid composite material can still deliver 387.4 mAh g−1 even at a high current density of 4 A g−1, significantly higher than 187.6 mAh g−1 for the pure NiCo2O4 microspheres. The outstanding electrochemical performance of the core-shell NiCo2O4@GO hybrid composite demonstrated that it has great potential as high-performance anode material for lithium-ion batteries.