Ultrathin Co3O4 nanosheets anchored on multi-heteroatom doped porous carbon derived from biowaste for high performance solid-state supercapacitors

Abstract

Low-cost multi-heteroatom doped porous carbons derived from agricultural waste were prepared as the base material. Then, the cobalt oxides nanosheets were anchored to the surface of the carbon material to obtain the composites. It was found that the adoption of porous carbon is of great significance for the improvement of materials properties. The presence of porous structure derived from carbon materials not only increases the stability of the material, but also facilitates the diffusion and transfer of electrolyte ions. Meanwhile, the flaky Co3O4 endows the material with high energy density and high charge transport efficiency. The resulted composite materials exhibit high specific surface area with low electrochemical impedance. Both aqueous and solid-state SCs were assembled separately. The energy density of aqueous SC can reach up to 42.5 Wh kg−1 at a power density of 746 W kg−1 and even with power density up to 30 kW kg−1 as the energy density still maintained 25 Wh kg−1. As for solid-state SC, the energy density can reach 40.6 μWh cm−2. The retention of solid-state SC can maintain at 87.1% even after 3000 cycle numbers. The excellent performance of composites enables them to be promising electrode materials for energy storage.