Cactus-like NiCo2O4@Nickel-plated fabric nano-flowers as flexible free-standing supercapacitor electrode

Abstract

Binary transition-metal oxides have caused wide public concern for energy storage as a result of its higher electrical conduction and electrochemical activity compared to single metal oxides in the past few years. However, its practical applications are severely limited by poor specific capacitance and cycling stability. Recently, an effective strategy for enhancing the electrochemical performance of supercapacitors has been demonstrated by proper structural design and optimization of material. Herein, cactus-like NiCo2O4@NPF nano-flower flexible supercapacitor electrodes assembled from 1D NiCo2O4 nanoneedles on 2D hollow metal networks by simple hydrothermal and calcination treatment. The unique nano-flower structure can construct multi-dimensional channels, which facilitate the transport of electrons and ions and significantly enhances the reaction kinetics at the interface between the electrolyte and the active materials. The NiCo2O4@NPF-1 electrode displays an outstanding electrochemical energy storage performance and the specific capacitance is 1106 F g−1 at 1 A g−1. Besides, the composite electrode exhibits a distinguished rate capability (633 F g−1 at 50 A g−1) and favorable cyclability (capacity retention of 92.2% after 2000 cycles). These exceptional results recommend that as-assembled NiCo2O4@NPF nano-flower hybrid material could be a hopeful contender for multifunctional flexible supercapacitor electrodes.