N-doped carbon-coated TiN exhibiting excellent electrochemical performance for supercapacitors

[Display omitted] •N-doped carbon-coated TiN (TiN/C) was fabricated using pyrrole as carbon source.•The TiN/C supercapacitor retains 92% of the initial capacitance after 5000 cycles.•The carbon coating raises the anti-oxidation yet remains the activity of TiN.•Asymmetric TiN/C//MnO2 supercapacitor reveals high energy and power density. TiN used as supercapacitor (SC) electrode in aqueous electrolyte is prone to suffering from oxidation, leading to poor electrical conductivity and electrochemical activity. In this work, TiN nanoparticles were synthesized at 530°C by the reaction between Ti powder and NH4Cl in stainless steel autoclaves, which further reacted with pyrrole at 550°C to yield N-doped carbon-coated TiN (TiN/C) with mesopores. TiN/C as electrode material for SC exhibits excellent electrochemical performance in 1M KOH electrolyte, achieving a specific capacitance of 102.6Fg−1 at a current density of 1Ag−1 and retaining a specific capacitance of 94.4Fg−1 after 5000 cycles (corresponding to capacitance retention of 92%). In particular, the TiN/C with a low operation voltage window and superior long-term cycling stability is a promising negative electrode for asymmetric SCs. The SC constructed by TiN/C and MnO2 reveals a high energy density of 17.2Whkg−1 as well as excellent cycling stability in 1M KOH electrolyte. The protective amorphous carbon coated on the TiN nanoparticles significantly improves the anti-oxidizability of TiN yet preserves the electrochemical activity via the loose carbon structure. Therefore, the TiN/C nanocomposite with low cost is promising and applicable in SCs.