Nitrogen Doped Intercalation TiO/TiN/TiCT Nanocomposite Electrodes with Enhanced Pseudocapacitance.

Layered two-dimensional titanium carbide (TiCT), as an outstanding MXene member, has captured increasing attention in supercapacitor applications due to its excellent chemical and physical properties. However, the low gravimetric capacitance of TiCT restricts its rapid development in such applications. Herein, this work demonstrates an effective and facile hydrothermal approach to synthesize nitrogen doped intercalation TiO/TiN/TiCT with greatly improved gravimetric capacitance and excellent cycling stability. The hexamethylenetetramine (CHN) in hydrothermal environment acted as the nitrogen source and intercalants, while the TiCT itself was the titanium source of TiO and TiN. We tested the optimized nitrogen doped intercalation TiO/TiN/TiCT electrodes in HSO, LiSO, NaSO, LiOH and KOH electrolytes, respectively. The electrode in HSO electrolyte delivered the best electrochemical performance with high gravimetric capacitance of 361 F g at 1 A g and excellent cycling stability of 85.8% after 10,000 charge/discharge cycles. A systematic study of material characterization combined with the electrochemical performances disclosed that TiO/TiN nanoparticles, the introduction of nitrogen and the NH intercalation efficaciously increased the specific surface areas, which is beneficial for facilitating electrolyte ions transportation. Given the excellent performance, nitrogen doped intercalation TiO/TiN/TiCT bodes well as a promising pseudocapacitor electrode for energy storage applications.