Hierarchical micro-/mesoporous N- and O-enriched carbon derived from disposable cashmere: a competitive cost-effective material for high-performance electrochemical capacitors

To obtain advanced carbon materials for next-generation electrochemical capacitors (ECs), it is critical to understand the synergetic effect of versatile carbon surface functionalities and the specific pore structure on their electrochemical performance. Herein, we developed a facile yet scalable fabrication of N- and O-enriched carbon with nanoscale to mesoscale porous structures from the disposable cashmere. The hierarchical cashmere-derived micro-/mesoporous carbon (CDMMC) was endowed with a desirable specific surface area (SSA, 1358 m(2) g(-1)), hierarchical porosity with high microporosity of similar to 45.5%, and high content of heteroatom functionalities (similar to 4 at% N and similar to 15.5 at% O). Even better electrochemical capacitance of the resulting CDMMC was obtained in 1 M H2SO4, benefiting from the hierarchical micro-/mesoporosity, large effective SSA and remarkable heteroatom (N, O) doping effects, that is, the smart combination of double layer and Faradaic contributions, compared to that in KOH. Furthermore, larger energy density (similar to 17.9 Wh kg(-1)) of the CDMMC-based symmetric device was obtained with organic electrolytes, compared to those with aqueous electrolytes.