The differentiation of elementary polarizations of FeF·3HO/C cathode material in LIB.

Time-dependent elementary polarizations of FeF·3HO/C cathode material were quantitatively investigated in dc polarization in order to determine the key factors that comprise the total polarization. The measurement of electrochemical impedance spectrum at a given state of charge and the subsequent least square fitting of its equivalent circuit allow the calculation of elementary contributions of individual kinetic step to the total polarization. The profiles of the calculations were well consistent with those of experiments based on the same states of charge, and the elementary contributions could be differentiated successfully which reveal that the solid-state diffusion process makes the largest contribution to the total polarization after 2.5 s discharge beginning with open-circuit voltage (OCV) level 3.5 V. The results may be helpful for the design of batteries of better performance with FeF cathode. [ABSTRACT FROM AUTHOR]