Construction of CoMo₂ S₄ Nanorods/Nanosheets Electrodes with Enhanced Electrochemical Properties for Asymmetric...

The construction of hierarchical nanostructures and the synergistic effect of bimetal compounds provide effective strategies to address the low energy density of supercapacitors. Herein, CoMo₂ S₄ (CMS) nanosheets anchored on homogeneous nanorods vertically distributed on nickel foam (NF) were fabricated using a two-step hydrothermal method. The hierarchical homostructure CMS materials heavily depend on the vulcanization parameter of the second step synthesis. As an electrode of supercapacitors, CoMo₂ S₄ exhibits a large specific capacity of 1992.85 F g^-1 at 2 mA cm^-2 , and specific capacity retention of 106 % through 8000 cycles when sulfurization condition was at 120 °C for 6 h (CMS/NF-120). Such excellent performances benefit from hierarchical homostructure, which can provide a large reaction surface area, fast ion/electron diffusion channels and rich active sites. Furthermore, the asymmetric pseudocapacitors device constructed with CMS/NF-120 and active carbon exhibits a maximum energy density of 39.8 Wh kg^-1 , and good long-term stability (80.1 % capacitance retention after 10,000 cycles).