Effects of electrolyte composition on the charge and discharge performances of LiNiO_2 positive electrode for lithium ion batteries

摘要

Charge and discharge behaviour of LiNiO_2 positive electrode has been examined in organic electrolytes with different compositions. The discharge capacity of the oxide electrode at a moderate cycling rate varied with the electrolyte composition. Redox responses in potential sweep voltammetry also depended on the kind of lithium salt and solvent of the electrolyte. Electrolyte solutions of relatively low ionic conductivity generally gave lower voltammetric responses and rate capability. A.c. impedance analysis of the LiNiO_2 electrode before and after the charge and discharge demonstrated that the surface chemistry of the oxide, depending on the electrolyte composition, has an important influence on the rate capability of the oxide electrode in organic electrolyte solutions.