KINETIC-STUDY OF THE LITHIUM ELECTROINSERTION IN V2O5 BY IMPEDANCE SPECTROSCOPY

The kinetics of the lithium electroinsertion in vanadium pentoxide was studied vs. LixV2O5 composition bronzes formed during the two first processes (0 < x < 1), by means of complex impedance spectroscopy between 104 and 10−3 Hz at 20° and 50°C in 1M LiClO4/propylene carbonate solutions. The interfacial charge transfer process is found to be independent of x. At 20°C, the exchange current density is equal to 1.3 ± 0.5 10−4 A/cm2 and the chemical coefficient diffusion, [formula omitted], varies between 10−9 and 10−11 cm2 s−1, with a minimum value for x ≅ 0.25. The partial conductivity σLi of lithium in V2O5 is found to vary between 10− 6 and 10−7 Ω−1 cm−1. The [formula omitted] and σLi values at 50°C are five to six times greater than those at 20°C. The dependence of [formula omitted] on the composition of the LixV2O5 bronzes composition was correlated with structural and thermodynamic data already reported in the literature. © 1990, The Electrochemical Society, Inc. All rights reserved.