Microporous carbons derived from nitrogen-rich triazatruxene-based porous organic polymers for efficient cathodic supercapacitors

Abstract

Lately, there has been growing interest in utilizing conjugated microporous polymers (CMPs) as favorable electrodes for storing energy. However, certain synthesized CMPs have exhibited limitations such as depressed conductivity as well as inefficient electrochemical properties, which have hindered their feasible use. In this regard, we effectively synthesized microporous carbonaceous materials via calcination followed by KOH activation processes for both TAT-Cz and TAT-BCz CMPs. The resulting microporous carbons showed noteworthy characteristics, including a significantly large surface area (up to 600 m² g⁻¹), notable pore volume (reaching 0.75 cm³ g⁻¹), superb thermal stabilization and char yield (up to 791 °C and 90%), and amorphous nature. In particular, the thermal treatment of TAT-Cz CMP at 800 °C produced the TAT-Cz-800, which displayed a remarkable electrochemical capacitance of 1005 F g⁻¹ at 1.0 A g⁻¹ current density. This outstanding capacitance value is comparable to those of other porous carbon materials. Additionally, TAT-Cz-800 demonstrated the best coulombic efficiencies over a span of 5000 cycles at 10 A g⁻¹ reaching 98.59%. Moreover, the excellent energy density for TAT-Cz-800 carbons was determined to be 139.58 W h kg⁻¹ at a power density of 500 W kg⁻¹. Interestingly, a two-electrode symmetric SC holding TAT-Cz-800 displayed a superb electrochemical capacitance of 458 F g⁻¹ at 1.0 A g⁻¹, and a higher energy density up to 63.61 W h kg⁻¹. The exceptional electrochemical efficacy of TAT-Cz-800 as an electrode for energy storage is likely due to its large surface area, highly porous carbon structure, and high degree of nitrogen and oxygen contents.