Self-assembly-template engineering nitrogen-doped carbon aerogels for high-rate supercapacitors

Abstract

Three-dimensional (3D) interconnected porous nitrogen-doped carbon aerogels (CAs) have been successfully prepared with polyvinyl alcohol and nitrogen-containing N-phenylethanolamine as carbon and in-situ nitrogen sources, and boric acid as both crosslinking agent and 3D self-template. After drying, carbonization and KOH-activation treatment, the as-obtained CAs exhibit large specific surface area, hierarchically porous structure, heteroatom doping and superhydrophilicity. The optimal sample shows a high surface area up to 2016m2g−1 with a total pore volume of 1.179cm3g−1. The synergistic effect of the reasonably hierarchical porosity, high effective surface area utilization, superhydrophilicity, and heteroatom pseudocapacitance are in favor of high specific capacitance of 467Fg−1 in three-electrode system and considerable cycle performance of 85.7%, 90.9% retention over 10,000 cycles at 20Ag−1 and 30Ag−1. Moreover, the symmetric supercapacitor configuration delivers an energy density of 22.75Whkg−1 at power density of 262.5Wkg−1 and 7.6Whkg−1 at power density of 9572Wkg−1. Here, we pioneer an in-situ self-template approach for fabricating hierarchically porous aerogels with a potential application in supplying a peak power for hybrid electric vehicles, memory backup systems, cold-starting assistants and especially electrochromic devices as demonstrated in our case.