Binder free mesoporous Ag-doped Co3O4 nanosheets with outstanding cyclic stability and rate capability for advanced supercapacitor applications

Well-defined mesoporous Ag-doped Co3O4 nanosheets (NSs) has been synthesized directly on Ni-foam (NF) via a facile hydrothermal and post-annealing approach. The tune bandgap and improved electrical conductivity of the Ag-doped Co3O4 sample are confirmed by UV-visible spectroscopy and two probe current-voltage (I-V) measurements. The Ag-doped Co3O4 sample exhibits a higher surface area (176 m(2)g(-1)) than that of the pristine Co3O4 sample (108 m(2)g(-1)). The Ag-doped Co3O4/NF based electrode shows superior specific capacitance of 1425 Fg(-1) at 1 Ag-1 and outstanding rate capability as it retains 92.84% of its initial specific capacitance (at 1 Ag-1) even at higher the current density of 10 Ag-1. Moreover, the specific capacitance of the material increases up to 104.7% of its initial capacitance for the first 2000 cycles, and then it gradually decreases to 96.4% after 5000 cycles. In fact, the superior electrochemical properties of the mesoporous Ag-doped Co3O4 nanosheets are attributed to its tuned bandgap, improved specific surface area, mesoporous architecture, and binder-free design. The electrochemical results revealed that the mesoporous Ag-doped Co3O4 NSs can be used as potential electrode material in the high-performance electrochemical capacitor. (C) 2020 Elsevier B.V. All rights reserved.