A nanostructured spinel LiMn2O4 electrode material was prepared via a room-temperature solid-state grinding reaction route starting with hydrated lithium acetate (LiAc·2H2O), manganese acetate (MnAc2·4H2O) and citric acid (C6H8O7·H2O) raw materials, followed by calcination of the precursor at 500°C. The material was characterized by X-ray diffraction (XRD) and transmission electron microscope techniques. The electrochemical performance of the LiMn2O4 electrodes in 2M Li2SO4, 1M LiNO3, 5M LiNO3 and 9M LiNO3 aqueous electrolytes was studied using cyclic voltammetry, ac impedance and galvanostatic charge/discharge methods. The LiMn2O4 electrode in 5M LiNO3 electrolyte exhibited good electrochemical performance in terms of specific capacity, rate dischargeability and charge/discharge cyclability, as evidenced by the charge/discharge results.