Layered Silicon-Based Nanosheets as Electrode for 4 V High-Performance Supercapacitor

Silicon-based materials have shown great potential and been widely studied in various fields. Unlike its unparalleled theoretical capacity as anodes for batteries, few investigations have been reported on silicon-based materials for applications in supercapacitors. Here, an electrode composed of layered silicon-based nanosheets, obtained through oxidation and exfoliation, for a supercapacitor operated up to 4 V is reported. These silicon-based nanosheets show an areal specific capacitance of 4.43 mF cm⁻² at 10 mV s⁻¹ while still retaining a specific capacitance of 834 µF cm⁻² even at an ultrahigh scan rate of 50 000 mV s⁻¹. The volumetric energy and power density of the supercapacitor are 7.65 mWh cm⁻³ and 9312 mW cm⁻³, respectively, and the electrode can operate for 12000 cycles in a potential window of 4 V at 2 A g⁻¹, while retaining 90.6% capacitance. These results indicate that the silicon-based nanosheets can be a competitive candidate as the supercapacitor electrode material.