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

In 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.