Electrochemical properties of brownmillerite structured KBiFe<inf>2</inf>O<inf>5</inf>

In the present work, brownmillerite KBiFe2O5 (KBFO), a relatively new multifunctional compound, has been explored as an electrode material for applications in supercapacitors. Polycrystalline KBFO is synthesized via citrate combustion method. The phase formation, crystallinity, composition and morphology of KBFO samples are investigated using XRD, HRTEM, XPS and FESEM. As synthesized KBFO sample possesses rectangular rod-like morphology with monoclinic crystal system. The electrochemical properties of KBFO were analyzed using Galvanostatic charge/discharge (GCD), Cyclic voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) in acidic, alkaline and neutral electrolyte media. GCD results show a promising energy storage property with remarkable 100% capacitive retention after 1000 cycles. CV results also establish the pseudocapacitive nature of KBFO in all electrolyte media. These features support the feasibility of exploitation of KBFO for advanced energy storage applications.