Biomass-derived carbon materials for high-performance supercapacitor electrodes

A low-cost and high-performance carbon material for supercapacitors is fabricated via a simple yet versatile strategy using a renewable natural resource: bean dregs. Owing to the natural properties of the heteroatom-enriched resource and the uniqueness of the fabrication approach, an optimized sample with plentiful heteroatoms (mainly O and N), well developed hierarchical porosity and highly ion-accessible surface area is obtained. The synergetic function of the heteroatom doping and the unique structural characteristics endows the as-prepared sample with an excellent combination of electric double layer capacitance and pseudo-capacitance, thus remarkably improving its electrochemical performance. As expected, it exhibits superior capacitive performance, including high specific capacitance, impressive rate performance, and excellent cycle stability. Considering the facile procedure and the easy-availability of raw material, this environmental-friendly and cost-effective method can be expected to perform extraordinarily in the widespread application of supercapacitors.