Synthesis and Electrochemical Characterization of LiNi 0.8 Co 0.2 O 2 as Cathode Material for Aqueous Rechargeable Lithium Batteries

Abstract

LiNi 0.8 Co 0.2 O 2 cathode material for lithium ion batteries is synthesized by reaction under autogenic pressure at elevated temperature (RAPET) method. The simple synthesis procedure is time and energy saving, and thus is promising for commercial application. The structure and stability of the material have been characterized by means of XRD and TG-DTA. The electrochemical properties of the LiNi 0.8 Co 0.2 O 2 cathode are investigated in 2 M Li 2 SO 4 aqueous electrolyte and they are compared to that in an organic electrolyte. A battery cell consisting of LiNi 0.8 Co 0.2 O 2 as cathode in 2 M Li 2 SO 4 solution is constructed in combination with LiTi 2 (PO 4 ) 3 as anode. The cell retained almost constant discharge capacity over hundred cycles. The electrochemical impedance spectral (EIS) studies in aqueous and nonaqueous electrolytes revealed that the mechanism of lithium ion intercalation and deintercalation processes in LiNi 0.8 Co 0.2 O 2 electrode follow almost similar mechanism in both aqueous and nonaqueous electrolytes. The chemical diffusion coefficient was calculated from slow scan rate cyclic voltammetry and EIS. © 2012 The Electrochemical Society.