Nanostructured N-doped Ti3C2/TiO2 composite for high-performance supercapacitor

Herein, the N-doped Ti3C2/TiO2 nanostructure has been synthesized via hydrothermal treatment and following annealing in NH3. TiO2 nanoparticles in-situ grow on the surface of Ti3C2 spontaneously, resulting in the stable electron transport between TiO2 and Ti3C2. Besides, Ti3C2 nanosheets as conductive substrates make up for the poor conductivity of TiO2. The doping of N in Ti3C2/TiO2 composite further improves the electrical conduction. The ultimate N-doped Ti3C2/TiO2 composite achieves a higher specific capacitance of 737.4 F g- 1 than Ti3C2 (324.4 F g- 1) at 0.5 A g- 1. More importantly, the composite displays a high specific capacitance retention of 81 % over 12,000 cycles. Besides, the assembled symmetrical supercapacitor (SSC) manifests an excellent specific capacitance of 236.4 F g- 1 at 1 A g- 1 and a comparable energy density of 32.8 Wh kg- 1 at the power density of 500 W kg- 1. This work provides promising guidance for the fabrication of durable electrodes for energy storage application.