Preparation and characterization of LiAl0.23Mn1.77O4 for supercapacitor electrodes

LiAl0.23Mn1.77O4 was synthesized by high temperature solid-state reaction. The structure and morphology of LiAl0.23Mn1.77O4 were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). The supercapacitive performances of LiAl0.23Mn1.77O4 materials were studied using galvanostatic charge/discharge measurements, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods in 2 mol L-1 (NH4)(2)SO4 solution. The results show that the LiAl0.23Mn1.77O4 electrode exhibits typical supercapacitive characteristics in aqueous (NH4)(2)SO4 electrolyte. The specific capacitance is up to 185 F g(-1) at current density of 2 mA cm(-2). The ohmic resistance (R-sol) is only 0.22 Omega. Besides, the electrodes showed a stable cycle life in the potential range of 0-1.0 V and retained 93% of initial specific capacitance over 100 cycles. (C) 2008 Elsevier B.V. All rights reserved.