Study on capacitance properties of the sputtered carbon doped titanium nitride electrode material for supercapacitor

Titanium nitride doped with carbon film (TiN/C) is designed as the electrode for supercapacitor since the titanium nitride has the pseudocapacitive nature. In this paper, the TiN/C films without any binder are prepared by using magnetron co-sputtering method. The surface of C doped TiN film changes into pyramid shape, which increases the porosity and surface roughness of the film, and enhances the formation of surface pseudocapacitive material TiOxNy, which promotes the super capacitive properties of TiN/C electrode. The TiN film electrode with ∼5.33 at.% doped C displays an outstanding capacitance performance with the maximum areal capacitance of 45.81 mF cm−2. It is 3 times that of the un-doped TiN (16.25 mF cm−2) at a scan rate of 10 mV s−1 in 0.5 M H2SO4 solution. It exhibits excellent electrochemical cycling stability and excellent reversibility with a decay rate of 3.72% after 5000 cycles. In addition, the TiN/C-2 electrode has the great capacitance performance and the large capacitance contribution with the value of 85%. The incorporation of C element to the transition metal nitride could be a feasible method to improve the capacitance performance of transition metal nitride electrode.