Electrochemical study of phase transition processes in lithium insertion in V2O5 electrodes

The lithium intercalation into a V2O5 substrate was studied by chronopotentiometry. The samples were prepared by atomic layer chemical vapor deposition which provides homogenous and coherent layers at the surface of titanium plates. During the charge-discharge process, various phase transitions occurred in the system Li-V2O5 which induced a large change in the diffusion coefficient of lithium. To obtain an accurate analysis of the intercalation mechanism, the diffusion equation with a variable diffusion coefficient was solved by digital simulation. The thermodynamic and kinetic properties of the system are represented by an analytical model based on the complementary error function. This procedure was useful for study of the electrode behavior in a large concentration range or in a large potential domain. The influence of various parameters, such as the thickness of the sample or the thermodynamic enhancement factor, were examined. (C) 2003 The Electrochemical Society.