Hybrid energy storage device from binder-free zinc-cobalt sulfide decorated biomass-derived carbon microspheres and pyrolyzed polyaniline nanotube-iron oxide

Abstract High-performance supercapacitors that merit superior power and energy densities, as well as long-term cycle durability are always of great significance as a building block of energy storage devices. Herein, an innovative strategy is developed to design hierarchical and unique porous structures of ternary metal sulfide nano-flake decorated porous hydrothermal carbon microspheres. Hierarchical microspheres of ternary zinc-cobalt sulfide nanosheet (NS) decorated biomass derived hydrothermal carbon spheres (HTCSs) are directly employed as the positive supercapacitor electrodes. In addition, composites of pyrolyzed polyaniline nanotubes (PPNTs) and iron oxide, receiving advantages from highly porous structure and modification of nitrogen as a heteroatom are used as the negative electrodes in the fabricated asymmetric supercapacitors (ASC). The assembled Zn-Co-S@HTCSs//Fe2O3@PPNTs asymmetric supercapacitor with a broad potential window not only delivered superior energy density (85.12 Wh.kg−1) at a reasonable power density of 460 W kg−1 but also rendered reasonable cycle durability. The advanced asymmetric design together with encouraging results presented herein makes these supercapacitors immensely promising for high-performance electronics.