Binder-less fabrication, some surface studies, and enhanced electrochemical performance of Co, Cu-embedded MnO2 thin film electrodes for supercapacitor application.

We report the fabrication of nanocystalline MnO 2 thin film-based electrode on a predeposited indium tin oxide (ITO) film on the glass substrate, using a binderless and simple two-electrode electrofabrication approach. Effects of Co and Cu incorporation on microstructural and electrochemical performance of the electrode were optimally and extensively investigated. The experimental results for the optimum fabrication conditions for Co@MnO 2 and Cu@MnO 2 and pure MnO 2 thin film-based electrode samples showed uniqueness in microstructural features, degrees of crystallinity and roughness, and high electrochemical energy storage performance. Co@MnO 2 film electrode exhibited remarkable specific capacitance (1068 Fg-1) and areal capacity (25.78 mAh cm−2) as against other electrode films (Cu@MnO 2 and pure MnO 2) which exhibited specific capacitances 837 and 438 F g−1 and areal capacities 10.6 and 4.9 mAh cm−2, respectively. Exceptional stabilities were also recorded for the composite samples (87.2% and 84.4% for Cu@MnO 2 and Co@MnO 2 thin film electrodes, respectively) against the pure MnO 2 film electrode sample (77.8%), after 2000 cycles. In addition, the short time constants (1.27 s and 1.31 s) were respectively realized for the fabricated Co@MnO 2 and Cu@MnO 2 electrode films as against the pure MnO 2 electrodes (4.35 s). These features observed in the composite electrode samples demonstrated an exhibition of faster ion response and higher rate capability by the samples. Moreover, the incorporation of Co into the MnO 2 electrode material relatively improved the supercapacitive activeness by enhancing the charge transition and transport. [ABSTRACT FROM AUTHOR]