High-temperature All Solid-state Microsupercapacitors Based on SiC Nanowire Electrode and YSZ Electrolyte.

We demonstrate a symmetric supercapacitor by using yttria-stabilized zirconia as the electrolyte and silicon carbide nanowires (NWs) as the electrode. The stacked symmetric SiCNWs/YSZ/SiCNWs supercapacitors exhibit excellent thermal stability and high areal capacitance at temperatures above 300 °C. The supercapacitor functions well at a record high temperature of 450 °C, yielding an areal capacitance of 92 μF cm-2 at a voltage scan rate of 100 mV s-1. At this temperature, it is also capable of withstanding current densities up to 50 μA cm-2, yielding a maximum areal power density of 100 μW cm-2. Good cycling stability is demonstrated with a capacitance retention of over 60% after 10,000 cycles at the operation temperature of 450 °C and a scan rate of 200 mV s-1.