Porous Carbon Derived from Sweet Potato Biomass as Electrode for Zinc-ion Hybrid Supercapacitors

Zinc-ion hybrid supercapacitors (Zn-HSC) with outstanding capacity, durable longevity and low cost offer an opportunity for the development of electrochemical energy storage devices. Nevertheless, the development of Zn-HSC is still in its initial stage and there are many problems exist. In particular, the difficulty caused by restricted adsorptive capability of carbon cathode significantly limits the energy density of Zn-HSC. Herein, a novel sort of activated carbon (AC) with high surface area of 3424 m(2) g(-1) was obtained from a common biomass through economical method for pyrolysis activation. The Zn-HSC demonstrated a high discharge capacitance (336 F g(-1) at 0.5 A g(-1)), remarkable energy density (112 Wh kg(-1) at 385 W kg(-1)), and 93% capacitance retention after 10000 cycles at 5 A g(-1).