Yeungnam University, Korea,
Keywords: P-type SrCu2O2, Ca-doping, electrical conductivity, supercapacitors, specific capacitance
Summary:Development of binary metal-oxides with multiple oxidation states and high electrical conductivity is of high interest for the application in supercapacitors. Herein, we prepared binary Sr-Cu metal oxides with and without Ca-doping by a solid-state chemical reaction. The binary metal-oxides exhibited good crystallinity and aggregated nanoparticles morphologies with the Ca-doping of about 10%. These Sr-Cu oxides-modified carbon cloth electrodes displayed a wide electrochemical potential window and the specific capacitance for the doped binary oxide was ca. 308.0 F.g-1 at a current and mass loading of 4 mA and 0.85 mg, respectively. While it was 33.49 F.g-1 for the undoped binary oxide at a current and mass loading of 4 mA and 0.88 mg, respectively. This significantly higher specific capacitance for the doped binary oxide compared to the undoped binary oxide can be attributed to the enhancement of the conductivity induced by Ca-doping. The specific capacitance of this doped binary oxide is higher or comparable with the reported other binary metal-oxides based supercapacitors, which can be ascribed to the improved rate of ions intercalation and deintercalation into the tunnels of doped Sr-Cu oxide in addition to its enhanced conductivity. The electrode exhibited good electrochemical stability with the capacity retention of 89.6% after 2000 charge-discharge cycles.