Flexible Asymmetric Supercapacitors Based upon Co9S8 Nanorod//Co3O4@RuO2 Nanosheet Arrays on Carbon Cloth

TLDR: Flexible asymmetric supercapacitors based on acicular Co9S8 nanorod arrays as positive materials and Co3O4@RuO2 nanosheet arrays as negative materials on woven carbon fabrics are fabricated and present excellent cycling performance at multirate currents and large currents after thousands of cycles.

Abstract: We have successfully fabricated flexible asymmetric supercapacitors (ASCs) based on acicular Co9S8 nanorod arrays as positive materials and Co3O4@RuO2 nanosheet arrays as negative materials on woven carbon fabrics. Co9S8 nanorod arrays were synthesized by a hydrothermal sulfuration treatment of acicular Co3O4 nanorod arrays, while the RuO2 was directly deposited on the Co3O4 nanorod arrays. Carbon cloth was selected as both the substrate and the current collector for its good conductivity, high flexibility, good physical strength, and lightweight architecture. Both aqueous KOH solutions and polyvinyl alcohol (PVA)/KOH were employed as electrolyte for electrochemical measurements. The as-fabricated ASCs can be cycled reversibly in the range of 0–1.6 V and exhibit superior electrochemical performance with an energy density of 1.21 mWh/cm3 at a power density of 13.29 W/cm3 in aqueous electrolyte and an energy density of 1.44 mWh/cm3 at the power density of 0.89 W/cm3 in solid-state electrolyte, which are alm...