Li rechargeable cells made with structural arrangement Li/membrane/LixV2O5 were examined under different charge states using ac impedance, environmental scanning electron microscope (ESEM), transmission electron microscope (TEM) and the high-resolution nuclear magnetic resonance (NMR). These states include charged, discharged, and over cycled. The lowest internal resistance was obtained from the cell at charged state; the resistance increased when the cell was discharged; and the highest resistance was obtained from the cell at over-cycled state. From the ESEM and TEM studies, it was found that the surface of cathode electrode was porous initially; however, it was coated with an amorphous film and porous features had also disappeared from the cell at over cycled state. In addition, higher concentration of aluminum was found at the surface of the cathode electrode in over-cycled cells. From NMR studies, Li ion signals, which correspond to Li ions in the liquid electrolyte, on the surface of LixV2O5 Cathode electrode, and inside the LixV2O5 cathode, were obtained. The mechanisms for capacity degradation and cycle lifetime of the cell are discussed. (c) 2005 Elsevier B.V. All rights reserved.