A Low-Cost and High-Purity Porous Carbon Spheres Based on Starch Gel Toward High-Performance Supercapacitors

Abstract

The development of low-cost, high-purity and high-performance porous carbon is of great significance for promoting the commercial application of supercapacitors. In this paper, porous carbon spheres (PCSs) with excellent electrochemical performance were obtained by carbonization and activation of starch gel spheres as precursor which is prepared by microemulsion process. The obtained PCSs exhibit both microporous and mesoporous structure, showing a large specific surface area of 1117.0 m2 g[Formula: see text] and exhibiting a high specific capacitance of 221.3 F g[Formula: see text]at a current density of 0.5 A g[Formula: see text] in aqueous electrolyte (and still displays capacity of 146.0 F g[Formula: see text] in ion liquid electrolyte). The PCSs//PCSs symmetric supercapacitor (SSC) based on aqueous electrolyte exhibits an energy density of 10.9 Wh kg[Formula: see text] at a power density of 300.0 W kg[Formula: see text], whereas that based on ion liquid electrolyte achieves a high energy density of 29.0 Wh kg[Formula: see text] at 650.0 W kg[Formula: see text]. The study provides a new idea to develop low-cost, high-purity and high-performance porous carbon materials for supercapacitors.