Nitrogen-enriched nanoporous polytriazine as efficient electrode material for high-performance supercapacitor application in non-aqueous medium with high cyclic stability

Abstract

Nitrogen-enriched nanoporous polytriazine (NENP) synthesized by conventional heating method possesses a high specific surface area (SABET) of 966 m2 g−1, controlled pore size distribution (1.6, 5, and 8.3 nm) and total pore volume of 2.73 cm3 g−1. The synthesized specimen was utilized as an electrode material for supercapacitor (SC) application in non-aqueous media. The electrodes of NENP were fabricated by two approaches viz., conventional binder-based method and a binder-free electrophoretic deposition (EPD) approach. In case of electrode fabrication by controlled EPD process, the mass of 0.58 mg was obtained as the optimized mass achieved at pH = 2, deposition voltage = 20 V and deposition time = 6 min. The optimized electrodes and tetraethylammonium tetrafluoroborate in adiponitrile (TEA-BF4/ADP) non-aqueous electrolyte were used to fabricate symmetric supercapacitor devices (SC). The SC device, with EPD- based binder-free electrodes, exhibited higher specific capacitance (Csp = 84 F g−1), energy density (Esp = 118.8 Wh kg−1) and power density (Psp = 17 kW kg−1) compared to SC device (49 F g−1, 68.8 Wh kg−1, and 11 kW kg−1 at 0.8 A g−1) fabricated using electrode made from the binder based method. To enhance the SC performance, KI was added as a redox additive to the non-aqueous electrolyte (TEA-BF4/ADP). The SC device, with NENP binder-free electrodes and redox-active nonaqueous electrolyte (TEA-BF4/ADP/KI), achieved the highest Csp, Esp, and Psp (112 F g−1, 150.5 Wh kg−1, and 27 kW kg−1) and demonstrated high cyclic stability (~80.2 % initial capacitance retention after 30,000 cycles, at 5 A g−1).