Lithium-Ion Intercalation Behavior of LiFePO[sub 4] in Aqueous and Nonaqueous Electrolyte Solutions

Lithium-ion intercalation behavior of in both aqueous and nonaqueous electrolyte solutions was extensively investigated. showed a much better rate capability in the aqueous electrolyte than in the nonaqueous electrolyte. Kinetic properties of particles were studied by cyclic voltammetry (CV) using a powder microelectrode. The apparent diffusion coefficients were evaluated from CV data, ranging from in to in , and in nonaqueous electrolyte. Electrochemical impedance spectroscopy demonstrated that the differences in the evaluated value of diffusion coefficients and the rate capability between two electrolyte systems are mainly due to the different interfacial charge transfer. A theoretical calculation with density functional theory was also employed to study the process of charge transfer at interface.