Multidimensional carbon template preparation of 3D multilayered TiC nanoflakes for high performance symmetric supercapacitor

Titanium carbide (TiC)-based electrodes are attractive in supercapacitor due to their ultra-high density and pseudocapacitive charge storage mechanism. However, TiC films with horizontal alignment of flakes or random nanostructures limit the high rate of charge transfer and hinder the migration of ions to redox active sites. In this work, the TiC nanotubes and three-dimensional interconnected nanoflakes are synthesized by electrodeposition and carbothermal treatment of carbon nanotube (CNT) film and graphite, respectively. To study the capacitance mechanism of TiC nanotube-interconnected branch (NTIB) films, the in-situ Raman spectrums of the TiC-NTIB negative electrode during the charge/discharge processes in H₂SO₄ show that hydronium is bonded to the terminal O during discharge, and debonding occurs during charging. The integrated TiC NTIB electrode is capable of operating at rates faster than that of carbon, conductive polymers or transition metal oxides, but still delivers a specific capacitance of 273 F g⁻¹ at 10 A g⁻¹ after repeating 2000 cycles at current densities of 1, 3, 5 and 10 A g⁻¹. The symmetric supercapacitor composed of the TiC NTIB electrodes delivers an energy density of 64.4 Wh kg⁻¹ (at 892.3 W kg⁻¹) and a power density of 9.5 kW kg⁻¹ (at 55.6 Wh kg⁻¹), and a good cycle stability (≈86.7% retention after 15,000 cycles).