Selectively designed hierarchical copper-cobalt oxysulfide nanoarchitectures for high-rate hybrid supercapacitors

Rational design of metal oxide-sulfide-based composite electrode materials with multi-functional nanoarchitectures, high electrochemical conductivity, and superior redox activity have attracted extensive attention in high-rate hybrid supercapacitors. Herein, the hierarchical binder-free copper-cobalt oxysulfide (Cu0.33Co0.67OxSy) nanoarchitectures with flower-like nanosheets and nanoplates are facilely synthesized on Ni-foam for hybrid supercapacitors using a simple and low-cost wet chemical method. The Cu0.33Co0.67OxSy-NFs demonstrated a high specific capacity of 193 mAh/cm2 (443.9 μAh/cm2) at current density of 3 mA cm− 2, with excellent cycling performance of 95 % even after 3000 charge-discharge cycles. In addition, an aqueous hybrid device was assembled using prepared Cu0.33Co0.67OxSy-NFs as positive and porous carbon as negative electrode, which demonstrated benchmark for energy storage properties. Specifically, the assembled device exhibited a high energy density of 0.33 mWh/cm2 and a power density of 2.1 mW/cm2 with high capacity retention (91 % after 5000 cycles at 20 mA cm−2). In view of practical applicability, the assembled hybrid devices can be able to power up a small wind fan for a long duration. The cost-effective single-step approach in designing high-performance cathode materials in this study provide a strategy for the design and manufacture of other ternary metal oxysulfides for high-performance energy storage devices.