The development of the impedance spectroscopy method to measure the particle dispersion degree in Lithium-ion battery (LIB) slurry

点击翻译按钮获取中文摘要

I combined both experiment and simulation methods to clarify the dielectric characteristics of LIB slurry. In the experiment, three slurries are extracted from cathode slurry. Meanwhile, cathode slurry is stirred at different rotational speeds. In the simulation, three different models are compared with the experimental slurries. The medium conductivity and particle conductivity are changed. The obtained Nyquist plots are fitted by circle fitting method. The characteristic resistances fitted by the circle fitting method are compared with those fitted by EEC. Meanwhile, the relaxation frequencies fitted by using the circle fitting method are quantitatively compared with those of experiment. Three main conclusions are shown as follows. Firstly, two particle dispersion behaviours which are CB aggregation and CB-bare LiCoO2 particles are able to be obtained in the case of lower n, while another two particle dispersion behaviours which are CB path and CB-coated LiCoO2 particles are able to be obtained in the case of higher n. In dielectric simulation, CB aggregation and CB-bare LiCoO2 particles are verified by lower medium conductivity and lower particle conductivity. CB path and CB-coated LiCoO2 particles are verefied;ed by higher medium conductivity and higher particle conductivity, respectively. However, compared with particle conductivity, medium conductivity plays important roles in determining particle dispersion because medium conductivity has the similar functions as n. Hence, CB path dominates the conductivity of cathode slurry than CB-coated LiCoO2 particles.