LiNi1/3Mn1/3Co1/3O2 cathode material is synthesized by reactions under autogenic pressure at elevated temperature (RAPET) method and its electrochemical behavior is studied in 5 M LiNO3 aqueous solution and compared with that in a nonaqueous electrolyte. In cyclic voltammetry, LiNi1/3Mn1/3Co1/3O2 electrode exhibits a pair of reversible redox peaks and the corresponding potential plateaus were observed during charge-discharge cycle. Potentiostatic intermittent titration technique (PITT) and electrochemical impedance spectral (EIS) data measured at various potentials are analyzed to determine the kinetic parameterswhich characterize intercalation/de-intercalation of lithium ions in both aqueous and nonaqueous electrolytes. A typical cell employing LiNi1/3Mn1/3Co1/3O2 as cathode and LiTi2(PO4)(3) as anode in 5 M LiNO3 solution delivers an average output voltage of 1.0 V with a specific capacity of 84 mAh g(-1). (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.058207jes] All rights reserved.