Preparation of MOFs derived nitrogen self-doped porous carbon and its electrochemical performance in mixed electrolytes

Abstract

Owing to the versatile chemical compositions and structures of metal-organic frameworks (MOFs), design and synthesis of MOFs derived complicated nano-structures has been a key topic in chemistry and materials science. Aimed at key issues such as low energy density of supercapacitors, {[Ag3(BTC)(IM)]·H2O}n (ABI) was synthesized using the hydrothermal method and nitrogen self-doped porous carbon ABIC-T was prepared using the one-step carbonization method. The electrochemical performances of ABIC-T in KOH and ASS-4.0 mixed electrolyte were investigated and the mechanism of mixed electrolyte reaction was clarified. The results indicated that the synthesized nitrogen self-doped porous carbon ABIC-750 has a spongy porous structure with specific surface area of 602 m2/g. At current density of 1.0 A/g, the specific capacitance of ABIC-750 in KOH (6 M) was 142.2 F/g and its capacitance retention after 5000 cycles was 91.05%. At current density of 1.0 A/g, the specific capacitance of ABIC-750 was 817.1 F/g in the ASS-4.0 mixed electrolyte. In other words, the energy density of ABIC-750 in the ASS-4.0 mixed electrolyte was 5.75 times of that in KOH (6 M). This can be attributed to the Faradaic pseudocapacitance developed by redox reactions of sodium alizarinsulfonate in the mixed electrolyte.