Silicon carbide nanowires as cathode materials for aqueous asymmetric supercapacitors

We report a high–performance asymmetric supercapacitors (ASCs) by assembling a silicon carbide nanowires cathode with a nitrogenous porous carbon anode. Utilizing a thermal evaporation technique, silicon carbide nanowires featuring a blend of 3C–, 2H–, and 6H–silicon carbide phases are synthesized on carbon fabric. The resulting binder–free cathode achieves a notable reversible capacitance of 27.33 mF cm⁻² at a current density of 0.2 mA cm⁻², outperforming numerous recently engineered electrodes made of single–crystal phases, including 4H–silicon carbide (12.8 mF cm⁻²) and 3C–silicon carbide (ranging from 9.56 to 16.7 mF cm⁻²). Furthermore, the aqueous asymmetric supercapacitors demonstrate rapid charge–discharge rates, exceptional rate performance, and impressive long–term cycling stability, with 91.68 % of capacity retained after 20,000 cycles of charging and discharging within a voltage range of 0–1.8 V. Additionally, a high energy density of 6.48 μWh cm⁻² is obtained at a power density of 900 μW cm⁻². Its performance is either superior to or comparable with previously reported supercapacitors devices, demonstrating significant energy storage capability.