General self-template synthesis of transition-metal oxide microspheres and their excellent charge storage properties

Abstract

Transition metal oxides are promising electrode materials for electrochemical energy storage and conversion to replace the precious metal-based electrode materials. Herein, we demonstrate a universal method for making flower-like transition metal oxides (NiO, Co3O4, NiCo2O4) microspheres as excellent electrode materials for electrochemical capacitors. These as-obtained flower-like microspheres organized from a large number of ultrathin nanosheets, which can provide high surface area and abundant mesoporous structures. Furthermore, the as-fabricated NiO, Co3O4 and NiCo2O4 microspheres exhibit high specific capacities of 1210.6, 802.5 and 842.5 F g−1 at a current density of 0.5 A g−1. Those microspheres also show good cyclability with capacities retention of 94.7%, 87% and 88.6% after 3000 cycles. The general self-template method holds great potential for the fabrication of high-performance charge storage devices.