Porous carbon materials with dual N, S-doping and uniform ultra-microporosity for high performance supercapacitors

Abstract

Ultra-microporosity and heteroatom-doping have been proved to be desired for carbon electrode materials of advanced supercapacitors. In this paper, dual N, S-doped carbon materials with high-developed ultra-micopores (∼0.70nm) are prepared by direct carbonization of potassium salts of m-amionphenol-m-mecaptophenol co-resin. The morphology, structure and surface properties of the carbon materials are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption, X-ray photoelectron spectroscopy (XPS), and Energy dispersive spectroscopy (EDS). It was found that the reactant ratio of phenols play an important role on the microscopy morphology, pore texture and heteroatom-doping of carbon materials. The potassium ions mono-dispersed in phenolic resins as a form of O−K+ deliver a homogenous “in-situ self-activation”, thus created developed ultra-microporosity with high uniformity, connectivity and short pore length. Due to the synergy effect of tailored ultra-microporosity and N, S, O-doping, the SNC-3:1-600 carbon shows a high specific capacitance of 250Fg−1, good capacitance retention of 61% in the range of 0.2–20Ag−1, low relaxation time constant of 0.71s in KOH electrolyte. The present preparation strategy is attractive and inspiring for preparation of tunable N, S-doped carbon materials for advanced supercapacitors.