Methanesulfonic acid-assisted synthesis of N/S co-doped hierarchically porous carbon for high performance supercapacitors

Abstract

Nitrogen and sulfur co-doped carbons are considered as electrode materials for high performance supercapacitors, while their further development is still limited by complicated synthesis procedure, unsatisfied structure and low energy density. Developing a simple synthetic strategy to obtain rationally structured carbon materials and high supercapacitor performance is remaining a grand challenge. Herein, we describe the synthesis of nitrogen and sulfur co-doped hierarchical porous carbons as high performance supercapacitors electrode by a methanesulfonic acid-assisted one-step carbonization and activation of the freeze-dried precursors mixture. The as-prepared carbon material not only exhibits ideally hierarchical pores, but also realizes uniform nitrogen and sulfur co-doping. In 6.0 M KOH electrolyte, the material can achieve a high specific capacitance of 272 F g−1 at 1.0 A g−1 and a promising rate performance retaining 172 F g−1 even at 100 A g−1. Moreover, a fabricated symmetric supercapacitor based on as-prepared nitrogen and sulfur co-doped hierarchical porous carbon delivers high energy densities of 12.4 W h kg−1 and 8.0 W h kg−1 in 6.0 M KOH liquid and KOH/PVA solid-state electrolytes, respectively. This work presents a simple and effective methanesulfonic acid-assisted approach for mass production of heteroatomic doping hierarchical porous carbons for future energy storage applications.