Improved supercapacitor performance of α-starch-derived porous carbon through gelatinization

Electric double layer capacitors (EDLC), as the energy storage devices, are generally based on those electrode materials of activated carbon, and biomass are becoming the main source of activated carbon in large scale. However, biomass-derived activated carbon has the disadvantage of low specific surface area (SBET) due to its big constructing blocks. Herein, gelatinized starch (α-starch) instead of untreated starch is chosen as carbon source, and interconnected porous activated carbon is obtained by tuning the EtOH/H2O content of gelatinization solution. Due to its high specific surface area up to 1863 m2 g−1, the gelatinized starch-derived activated carbon(SAC) exhibits an improved specific capacitance 335.6 F g−1 at 0.5 A g−1 (305.33 F g−1 at 1A g−1 vs. 103 F g−1 for untreated starch), which also delivers and 245.85 F g−1 at 10 A g−1 and keeps 96% retention of its initial capacitance even after 20, 000 cycles.