Evaluation of apparent lithium-ion diffusion coefficients in FePO4/LiFePO4 cathode material particles from linear non-equilibrium thermodynamics and principle of electroneutrality

摘要

A generalized mathematical model, which describes the process of lithium extraction/insertion in active material particles of insertion cathodes, is developed from linear non-equilibrium thermodynamics and the principle of electroneutrality. The model reveals theoretical relations between the intrinsic and apparent transport parameters of lithium-ions and electrons. Calculation formulas for apparent lithium-ion diffusion coefficient D-1* are deduced from the model. A simple trial calculation is introduced to evaluate the cross-phenomenological coefficient of the Onsager reciprocal relationship.