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

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 degrees C by the reaction between Ti powder and NH4Cl in stainless steel autoclaves, which further reacted with pyrrole at 550 degrees C to yield N-doped carbon-coated TiN (TiN/C) with mesopores. TiN/C as electrode material for SC exhibits excellent electrochemical performance in 1 M KOH electrolyte, achieving a specific capacitance of 102.6 F g(-1) at a current density of 1 A g(-1) and retaining a specific capacitance of 94.4 F g(-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 17.2 Wh kg(-1) as well as excellent cycling stability in 1 M 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. (C) 2017 Elsevier Ltd. All rights reserved.