Abstract
We demonstrate a symmetric supercapacitor by using yttria-stabilized zirconia (YSZ) as the electrolyte and silicon carbide nanowires (SiC NWs) as the electrode. The stacked symmetric SiC NWs/YSZ/SiC NWs 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 .