Hierarchical NiO–In2O3microflower (3D)/ nanorod (1D) hetero-architecture as a supercapattery electrode with excellent cyclic stability
Three-dimensional (3D) hybrid nanostructured electrodes based on one-dimensional (1D) nanorod arrays have recently attracted great attention owing to their synergistic effect of three-dimensional nanostructures and application in energy storage and conversion devices. Here, we designed a heterostructured supercapacitor electrode from a combination of NiO and In2O3 with a hierarchical hybrid microstructure on nickel foam (NF). Simultaneous heterogeneous growth of 1D nanorod-supported 3D microflower structures on nickel foam enhanced the non-capacitive faradaic energy storage performance due to the synergistic contribution from hierarchical hybrid nanostructure. The heterostructured electrode exhibits a high specific capacitance of 766.65 C g-1 at 5 A g-1 and remains as high as 285.12 C g-1 at 30 A g-1, which are significant than their individual oxides. The composite electrode shows an excellent rate performance as a sandwich type symmetric device, offering a high specific energy of 26.24 Wh kg-1 at a high power of 1752.8 W kg-1. The device shows a long term cyclic stability with 79% retention after 50,000 cycles, which is remarkable for an oxide based pseudocapacitor. These results suggest that NiO-In2O3 with hybrid micro/nano architecture could be a promising electrode for next generation supercapatteries.