High Capacitive Performance of N,O-Codoped Carbon Aerogels Synthesized via a One-Step Chemical Blowing and In Situ Activation Process

Biomass and its derivatives, with their renewable characteristics, cost-effectiveness, and controllable structural and compositional properties, are promising precursors for carbon materials. Herein, N,O-codoped carbon aerogels were synthesized by carbonization and zinc nitrate activation of histidine. The specific surface area (SSA) was markedly increased with the addition of zinc nitrate, and the maximum value achieved 853 m² g^-1 for ZHC-11 obtained with the molar ratio of 1:1 between histidine and zinc nitrate. The D/G-band intensity ratio increased from 1.55 for the histidine-derived control sample HC to 1.65 for ZHC-11, indicating the enhancement of amorphous feature. The nitrogen content increased from 6.5% for HC to 1.60 for ZHC-11. The optimized microstructure and enriched heteroatom doping are beneficial to the capacitance performance. The optimum electrode exhibited 234.1 F g^-1 at 0.1 A g^-1 and maintained 116.5 F g^-1 at 60 A g^-1 in a three-electrode system. In particular, the symmetric supercapacitor showed 121.9 F g^-1 and 19.5 Wh kg^-1 at 0.2 A g^-1. This research offers guidance on the cost-effective synthesis of carbon materials for supercapacitors, while also providing novel insights to realize the complete utilization of biomass derivatives.