Abstract: Kinetics of electrode processes of LiFePO4 in saturated LiNO3 solution was investigated by analyses of cyclic voltammetry (CV), charge/discharge test, and potentiostatic intermittent titration (PITT). The results showed that LiFePO4 had good electrochemical reversibility in saturated LiNO3 solution. The first discharge capacity was about 116.2 mAh•g−1, and its charge/discharge efficiency was 92%. The lithium diffusion coefficients, corresponding to anodic peak and cathodic peak in LiFePO4, obtained from CV were 4.3×10−11 cm2•s−1 and 3.8×10−11 cm2•s−1. The lithium diffusion coefficients obtained from PITT varied with potentials, and the lowest value was about 5.5×10−11 cm2•s−1, coinciding with the voltage plateau region in the charge curves.

Key words: Aqueous lithium-ion battery, LiFePO4, Cyclic voltammetry, Potentiostatic intermittent titration technique, Diffusion coefficient