Flexible Nitrogen Doped SiC Nanoarray for Ultrafast Capacitive Energy Storage

Abstract

The current trend with integrated energy-storage units in portable electronics lies in continuous advancements in nanostructured materials, thin-film manufacture technologies, and device architectures with enhanced functionality and reliability of existing components. Despite this, it is still challenging to provide cost-efficient solution to further improve the energy and power densities and cyclability of supercapacitors (SCs), especially at ultrafast rates while maintaining their environmentally friendly and even well-run at arbitrary harsh environments character. In this contribution, we report the fabrication of quasi-aligned single crystalline 3<i>C</i>-SiC nanowire (3<i>C</i>-SiCNW) array with tailored shapes and nitrogen-doping (N-doping). The resultant large-scale SiCNWs were directly grown on the surface of a flexible carbon fabric <i>via</i> a simple chemical vapor deposition method. We found that the SC performance of SiCNW arrays can be substantially enhanced by nitrogen doping, which could favor a more localized impurity state near the conduction band edge that greatly improves the quantum capacitance and hence increases the bulk capacitance and the high-power capability. The measured areal capacitances are higher with values of 4.8 and 4.7 mF cm^–2, in aqueous and gel electrolytes, respectively. The all-solid-state flexible textile-based SCs (TSCs) made with these electrodes are mechanically robust under bent and twisted states. Further, they show a power density of 72.3 mW cm^–2 that is higher than that of electrolytic capacitors, and an energy density of 1.2 × 10^–4 mW·h cm^–2, in association with superior rate ability, cyclability, and being environmentally friendly. Such SiCNW–TSC devices allow for operations at ultrahigh rate up to 30 V s^–1, 2 orders of magnitude higher than that of conventional supercapacitors. All these data are comparable to the reported results for 1D nanostructure-based carbon nanotubes (CNTs) or graphenes, thus showing the promising application as large-area flexible textile electronics