La0.75Sr0.25Cr0.5Mn0.5O3/Graphene Oxide-Based Composite Electrodes for Energy Storage Applications

Abstract

This study aims to produce La0.75Sr0.25Cr0.5Mn0.5O3 (LSCM)/graphene oxide (GO)-based composite electrode for energy storage applications. Perovskite was synthesized by solution combustion method. Graphene was synthesized by improved Hummers’ method. Synthesized active material was coated on porous Ni foam by vacuum centrifuge mixing. Effect of GO content on specific capacitance (Csp) of LSCM was studied by varying GO content from 1-7 wt. %. As synthesized perovskite and GO were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy and Fourier transform infrared spectroscopy. Electrochemical characterization was carried out by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in 3 M KOH. Electrochemical characterization revealed that LSCM electrode showed maximum Csp of 751 Fg-1 at 1 mVs-1. By increasing GO content from 1 wt. % to 3 wt. % and 5 wt. %, Csp was increased to 930 Fg-1, 1137 Fg-1 and 1223 Fg-1 respectively. Further evaluation of CV results revealed that predominant charge storage mechanism of electrodes was Faradic in nature which exhibited distinct redox peaks. EIS revealed that LSCM-5%GO electrode showed lowest charge transfer resistance among other electrodes. Furthermore, LSCM-5%GO electrode showed 93 % charge retention after 3000 charge-discharge cycles.