Binder Free Ternary Metal Sulfide CoNi2S2 with Coral-Like Morphology as High Performance Supercapacitor

Coral-like CoNi2S2 is in situ grown on nickel foam current collector using two step hydrothermal processes as binder free high performance supercapacitor. CoNi2S2 nanoparticles aggregated on the micron scale porous frame coral-like structure has both increased electroactive surface areas and utilization efficiency at high mass loading. The coral-like structure provides rough and porous texture with many nanoscale grooves and nanoparticles on the surface, which could be used as electrolyte reservoirs that will bring the internal active surface layers directly into contact with the electrolyte and result in fast redox reactions even at high current densities. The as-synthesized sample shows high specific capacitance of 2864 F/g at current density of 1 A/g and areal capacitance of 14.32 F/cm(2) at current density of 5 mA/cm(2) with good rate capability of 50% as current density increased from 5 to 100 mA/cm(2). Moreover, it shows excellent cycling stability of 117% retention after 1,000 cycles of charge-discharge and 96% retention after 4,000 cycles of charge-discharge by applying current density of 20 mA/cm(2). Such high performance electrode material may get great application in future energy storage device.