Robust High‐Temperature Supercapacitors Based on SiC Nanowires

Abstract Currently, the exploration of energy conversion/storage devices for high‐temperature operation with desired stability is still a grand challenge. In the present work, the high‐temperature supercapacitors (SCs) based on SiC nanowires as the electrode materials are reported, which are synthesized via pyrolysis of polymeric precursors followed by etching for creating more active sites with enhanced surface area. In 2.0 m KCl aqueous electrolyte, the as‐fabricated electrode based on etched SiC nanowires delivers a specific capacitance of 23.6 mF cm –2 (29.5 F g –1 ) at a current density of 0.2 mA cm –2 (0.25 A g –1 ), which is ≈3.3 times to that of the counterpart without etching (7.19 mF cm –2 ). The as‐constructed ionic‐liquid‐based SCs can endure the operation temperatures up to 150 °C with a capacitance retention of 80% for 10 000 cycles, which drops only ≈6% in comparison to that at 0 °C. Even under progressive variation in temperatures ranged between 0 and 150 °C, the capacitance retentions keep higher than 76% for 12 000 cycles, representing their promising to be serviced as robust SCs against high‐temperature harsh conditions for energy storage.