Determination of the chemical diffusion coefficient of lithium in Li_3V_2(PO_4)_3

摘要

The chemical diffusion of lithium ion in Li_3V_2(PO_4)_3 were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods. The CV results show that there exists a linear relationship between the peak current (i_p) and the square root of the scan rate (v~(1/2)). The impedance spectrum exhibits a single semicircle and a straight line in a very low frequency region. A linear behavior was observed for every curve of the real resistance as a function of the inverse square root of the angular frequency in a very low frequency region. The obtained chemical diffusion coefficient from EIS measurements varies within 10~(-9) to 10~(-8) cm~2·s~(-1), in good agreement with those from CV results.