Ag and Cr oxide nanodots sputter decorated over Mn-Co-Cu ternary metal oxide nanostructures for high-performance supercapacitor

Abstract

Hybrid nanostructures of quaternary composite of transition metal oxides (QCTMO) are fabricated by sputter depositing nano-dots of silver oxide or chromium oxide over flower-like nanostructures of manganese-cobalt-copper (MCC) ternary metal oxide. QCTMO electrodes are fabricated by magnetron assisted DC sputtering using different plasma powers. The presence of four different multivalent metal ions increases the redox sites, while the hybrid nature of the nanostructures increases the electrochemically active surface area. The synergistic effects result in enhancing the performance of the electrode. We showed that plasma power can be used to control the morphology and electrochemical properties of QCTMO electrodes. Chromium oxide nano-dots sputter deposited over MCC at 65 W showed the best performance with specific capacitance of 2261 F g−1 at a scan rate of 1 mV s−1 and specific capacity of 603 C g−1 at 5 mA cm−2. Solid-state symmetric supercapacitor fabricated with this electrode shows a retention in capacitance of 93 % after 4000 charge-discharge cycles and high energy density of 106 W h kg−1 at 3236.3 W kg−1 of power density.