Electrodeposition preparation of NiCo2S4 nanoparticles on a N-doped activated carbon modified graphene film for asymmetric all-solid-state supercapacitors

Abstract

In this work, NiCo₂S₄ nanoparticles were anchored on the surface of nitrogen doped activated carbon modified graphene (GNAC) by simple electrodeposition to prepare GNAC/NiCo₂S₄-15 composite electrode materials for high-performance supercapacitors. The insertion of nitrogen-doped activated carbon between graphene sheets effectively prevented the self-accumulation of graphene layers and provided a large number of active sites for a uniform growth of NiCo₂S₄ nanoparticles. Due to the synergistic effect between NiCo₂S₄ and graphene nanosheets, the GNAC/NiCo₂S₄-15 electrode showed a high specific capacitance (1495 mF cm⁻² at a current density of 1 mA cm⁻²) and excellent cycling performance (the area ratio capacitance retained 88% after 3000 cycles). In addition, an asymmetric supercapacitor (ASC) was assembled with GNAC/NiCo₂S₄-15 and GNAC as positive and negative electrodes, respectively. At a power density of 3.834 mW cm⁻³, the prepared ASC provides a significant energy density of 0.613 mW h cm⁻³, which offers great prospects for the application of supercapacitors.