A High‐Energy Density Asymmetric Supercapacitor Based on Fe2O3 Nanoneedle Arrays and NiCo2O4/Ni(OH)2 Hybrid Nanosheet Arrays Grown on SiC Nanowire Networks as Free‐Standing Advanced Electrodes

Abstract

AbstractIn this paper, a novel freestanding core‐branch negative and positive electrode material through integrating trim aligned Fe2O3 nanoneedle arrays (Fe2O3 NNAs) is first proposed with typical mesoporous structures and NiCo2O4/Ni(OH)2 hybrid nanosheet arrays (NiCo2O4/Ni(OH)2 HNAs) on SiC nanowire (SiC NW) skeletons with outstanding resistance to oxidation and corrosion, good conductivity, and large‐specific surface area. The original built SiC NWs@Fe2O3 NNAs is validated to be a highly capacitive negative electrode (721 F g−1 at 2 A g−1, i.e., 1 F cm−2 at 2.8 mA cm−2), matching well with the similarly constructed SiC NWs@NiCo2O4/Ni(OH)2 HNAs positive electrode (2580 F g−1 at 4 A g−1, i.e., 3.12 F cm−2 at 4.8 mA cm−2). Contributed by the uniquely engineered electrodes, a high‐performance asymmetric supercapacitor (ASC) is developed, which can exhibit a maximum energy density of 103 W h kg−1 at a power density of 3.5 kW kg−1, even when charging the device within 6.5 s, the energy density can still maintain as high as 45 W h kg−1 at 26.1 kW kg−1, and the ASC manifests long cycling lifespan with 86.6% capacitance retention even after 5000 cycles. This pioneering work not only offers an attractive strategy for rational construction of high‐performance SiC NW‐based nanostructured electrodes materials, but also provides a fresh route for manufacturing next‐generation high‐energy storage and conversion systems.