The production of hydrochar-based hierarchical porous carbons for use as electrochemical supercapacitor electrode materials

A comparative study of various hydrochar-based porous carbons was carried out. These porous carbons, synthesized from biomass by H3PO4, NaOH and KOH activation, were examined for use in supercapacitors. The micropores and mesopores had been introduced into the hydrochar simultaneously. Porous carbons exhibited different electrochemical performance due to the difference of their porosity. The prepared carbons showed a hierarchical porous structure, the corresponding BET surface areas and pore volumes were 1355–3322 m2/g and 1.45–2.53 cm3/g. The highest specific capacitance was 179.4 F/g at a current density of 6.25 A/g, and appeared to be a promising electrode material for supercapacitors.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Porous carbons were produced from biomass-based hydrochar by three activators activation. ► A comparative study of porous carbons was carried out. ► Porous carbons were examined for use in supercapacitors. ► The preparation method can be extended to other biomass-based hydrochar.