Electrochemical performance of Co2FeAl full heusler alloy as electrode materials for energy storage applications

Abstract

The structural, magnetic and electronic properties of full Heusler alloys provide a unique system to study both electrochemical charge-storage mechanisms and performance. The Co2FeAl full Heusler alloy nanoparticles are synthesized by co-precipitation method using different molarity of the precursors ranging from 1.2 to 2.0 M. Xray diffraction analysis confirmed the successful formation of the Heusler alloy phase with maximum crystallite size of 21 nm at 2.0 M. The magnetic measurements showed that the material is ferromagnetic with maximum saturation magnetization 129 emu/g among lower coercivity value 79 Oe at 2.0 M. Scanning electron microscopy (SEM) confirmed the agglomerated interconnected nanoparticles with granular surface morphology. The optimized sample showed the surface charge of-29.1 mV by zeta potential analysis, resulting good colloidal stability and good characteristics of the electrode-electrolyte interface. The electrochemical characterizations showed that the electrochemical performance is highly sensitive to precursor molarity, as obtained from cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The specific capacitance of 2.0 M Co2FeAl is found to be the highest 471 F/g at 1 A/g, along with reduced charge-transfer resistance and improved electrochemical kinetics. The charge-storage mechanism is found to be mixed, with both Faradaic diffusion-controlled reactions and capacitive surface-controlled reactions, by kinetic analysis. The obtained results indicate that the precursor molarity significantly influences the electrochemical properties of Co2FeAl nanoparticles and also give insight into their potential applicability as electrode material for energy storage applications.