LixV2O5 (0.4 < x < 1.4) prepared by solid-state reaction were studied by Li-7 and V-51 NMR spectroscopy. Li-7 NMR spectra showed a narrowing of the line width in relation to Li+ ionic diffusion. Analysis of LixV(2)O(5) using a Debye-type relaxation model showed a low activation energy similar to 0.07 eV in the sample of x = 0.4 below room temperature, and revealed a Li(+)ionic diffusion with larger activation energy similar to 0.5 eV above 450 K in lithium-rich samples. The latter is ascribed to the existence of a multi-phase system comprising stable epsilon- and gamma-phases, resulting from complicated phase transitions at high temperature. These shapes and shifts enable the classification of the beta-, epsilon-, delta-, and gamma-phases. The ionic diffusion of Li+ ions is discussed in relation to the complicated phase transitions. (c) 2005 Elsevier B.V. All rights reserved.