Template-assisted synthesis of porous carbon derived from biomass for enhanced supercapacitor performance

Carbon-based electrode materials have received widespread interest in supercapacitors because of their tunable structure, high chemical and physical stability, and low cost. The hard template method is considered as a potential strategy for fabricating porous carbons with controllable structures. However, porous carbons with satisfactory capacitance are always fabricated using an expensive template. Therefore, a simple and low-cost template strategy is necessary to construct high specific capacity porous carbon for supercapacitors. Herein, we proposed a facile and cost-effective method to fabricate biomass-derived porous carbon with a controllable structure using alginate as precursor. The in-situ formation of Fe(OH) 3 nanoparticles was employed as a hard template to construct interconnect microchannels, which could effectively increase capacitive active sites and promote electrolyte diffusion during the electrochemical process. The optimized sample displayed a high specific capacitance of 302 F g −1 at a current density of 0.5 A g −1 in 6 M KOH electrolyte and outstanding cycling stability with the capacitance retention of 88.39 % after 10,000 cycles at 5 A g −1 . In addition, a symmetric supercapacitor assembled by Fe-SA-C-1.5 electrodes showed an energy density of 11.32 W h kg −1 at a power density of 250 W kg −1 . This work offers a promising approach to construct high-performance electrodes for supercapacitors. • A simple and low-cost template strategy to construct porous carbons is developed. • Biomass as a source of carbon is low cost and widely available. • Assembled supercapacitors can maintain high energy density even at high power densities.