Scalable synthesis of N,S co-doped honeycomb-like porous carbon with micropore-dominance for ultrahigh volumetric-performance supercapacitors

Abstract

The conversion of low-cost, sustainable biomass into high-value porous carbon as an electrode material for supercapacitors has attracted considerable recent attention. Almost all efforts are focused on developing advanced carbon electrode materials without conducting large-scale experiments. Utilizing cotton pulp board as the prototype, we demonstrate that honeycomb-like porous carbon could be completely and repeatedly obtained by a one-step activation method. The preparation method is facile and industrially feasible, and could be used for the scalable production of multiple heteroatom-doped honeycomb-like porous carbon (MHDHPC) with excellent reproducibility and high yield. MHDHPC exhibits ultrahigh gravimetric capacitance and volumetric capacitance due to its high surface area, ultrahigh microporosity, relatively high density and surface heteroatom-rich nature. A MHDHPC//MHDHPC based symmetric supercapacitor can deliver a superior volumetric energy density of 13.1 Wh L⁻¹ in 6 M KOH. These exciting results provide a sustainable, scalable and low-cost method to prepare MHDHPC for high volumetric-performance supercapacitors.