Single-Crystalline, Metallic TiC Nanowires for Highly Robust and Wide-Temperature Electrochemical Energy Storage

Customized electrode materials with good temperature adaptability and high-rate capability are critical to the development of wide-temperature power sources. Herein, high-quality TiC nanowires are uniformly grown on flexible carbon cloth as free-standing electric-double-layer supercapacitor electrode. The TiC nanowires, 20-40 nm wide and 3-6 µm long, are single-crystalline and highly conductive that is close to typical metal. Symmetric supercapacitors are constructed with ionic liquid electrolyte and TiC nanowires electrodes as wide-temperature and long-cycle stable power source. Ultrastable high-rate cycling life of TiC nanowire arrays electrodes is demonstrated with capacitance retention of 96.8% at 60 °C (≈440 F g^-1 ), 99% at 25 °C (≈400 F g^-1 ), and 98% at -25 °C (≈240 F g^-1 ) after 50 000 cycles at 10 A g^-1 . Moreover, due to high electrical conductivity, the TiC nanowire arrays show ultrafast energy release with a fast response time constant of ≈0.7 ms. The results demonstrate the viability of metal carbide nanostructures as wide-temperature, robust electrode materials for high-rate and ultrastable supercapacitors.