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

Abstract

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 m² g⁻¹), hierarchical porosity with high microporosity of ∼45.5%, and high content of heteroatom functionalities (∼4 at% N and ∼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 (∼17.9 Wh kg⁻¹) of the CDMMC-based symmetric device was obtained with organic electrolytes, compared to those with aqueous electrolytes.