Chemical diffusion coefficient of lithium ion in Li3V2(PO4)3 cathode material

Abstract The kinetic properties of monoclinic lithium vanadium phosphate were investigated by potential step chronoamperometry (PSCA) and electrochemical impedance spectroscopy (EIS) method. The PSCA results show that there exists a linear relationship between the current and the square root of the time. The D Li values of lithium ion in Li 3- x V 2 (PO 4 ) 3 under various initial potentials of 3.41, 3.67, 3.91 and 4.07 V (vs Li/Li + ) obtained from PSCA are 1.26 × 10 − 9 , 2.38 × 10 − 9 , 2.27 × 10 − 9 and 2.22 × 10 − 9  cm 2 ·s − 1 , respectively. Over the measuring temperature range 15–65 °C, the diffusion coefficient increased from 2.67 × 10 − 8  cm 2 ·s − 1 (at 15 °C) to 1.80 × 10 − 7  cm 2 ·s − 1 (at 65 °C) as the measuring temperature increased.