Reduced graphene oxide networks as an effective buffer matrix to improve the electrode performance of porous NiCo2O4 nanoplates for lithium-ion batteries

Abstract

Transition metal oxides are promising high-capacity anode materials for next-generation lithium-ion batteries. However, their cycle life remains a limiting factor with respect to their commercial applications. The development of transition-metal oxide anode materials with long lifespans through a facile route has become an important issue. A straightforward strategy is designed for the fabrication of a NiCo₂O₄ nanoplates–reduced graphene oxide sheets (NiCo₂O₄–RGO) composite. It displays a high reversible capacity of 816 mA h g⁻¹ over 70 cycles with 80.1% capacity retention of the 2nd cycle and excellent rate capability. Its rate capability and cycling stability are enhanced in comparison with those of pure NiCo₂O₄ nanoplates. The as-obtained nanocomposite avoids the problems of dispersion and aggregation induced by cracking or pulverization of the transition-metal oxide upon cycling. The graphene or reduced graphene oxide not only works as a substrate to provide room for loading scattered grains, but also serves as a conductive network to facilitate the collection and transportation of electrons during the cycling, indirectly increasing the conductivity of NiCo₂O₄.