Polyethylene oxide (PEO)/LixV(2-delta)O(4-delta) nanocomposites were prepared in aqueous solution. Characterization of the nanocomposites using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), and Fourier transform infrared spectrum (FTIR) shows that polymer chains intercalate inorganic host lamella and exhibit lattice expansion along the stacking direction of 4.2 Angstrom. A possible model for the structure of the nanocomposite is also provided.