Bismuth manganese oxide based electrodes for asymmetric coin cell supercapacitor.

[Display omitted] • Bismuth manganese oxide nanoflakes are synthesised by one step hydrothermal method. • Kinetics of charge transfer was explained using different techniques. • The diffusion and capacitive controlled contribution are differentiatedon the basis of CV data. • Coin cell device is fabricated for good performance practical application. Binary metal oxides are deposited via simple chemical routes for high-performance energy storage applications. In this work, we developed nanostructures of BiMnO 3 on Ni foam using a hydrothermal method. Initially, the (0 1 0) and (1 1 0) planes confirmed the presence of the BiMnO 3 phase. Snow fungus-like nanostructure was transferred to porous interconnected nanoflakes with an increase in deposition time. These nanoflakes serve as large active sites that are beneficial for the diffusion of electrolytic ions that enhance the charge storage and transport process. Consequently, the two-dimensional interconnected nanoflakes showed a high diffusion coefficient, standard rate constant, and minimum transfer coefficient. In addition, BiMnO 3 exhibited an aerial capacitance of 6000 mF cm−2 (1500 Fg−1) with an energy density of 102 Wh kg−1 at an applied current density of 20 mA cm−2. For practical applications, an asymmetric coin cell (ACC) device was assembled using BiMnO 3 as the positive electrode and activated carbon as the negative electrode in 3 M aqueous KOH as an electrolyte. The fabricated ACC device had an energy density of 14.4 Wh kg−1 at a power density of 50 W kg−1 with a 1.2 V potential; the capacitive retention was 90 %, with 97 % Coulombic efficiency up to 5000 cycles. Accordingly, the results determined that BiMnO 3 can be used as an electrode material for high-performance energy storage applications. [ABSTRACT FROM AUTHOR]