The electrochemical and gravimetric behavior of a nanocomposite ([PSPAN](0.3)V2O5. nH(2)O]) comprised of poly(N-propane sulfonic acid aniline) (PSPAN) and vanadium pentoxide xerogel are described. Electrochemical quartz crystal microbalance (EQCM) measurements show that the charge compensation process in this nanocomposite occurs predominantly by Li+ transport with a small amount of accompanying solvent, especially at low scan rates. The diffusion coefficients for Li+ in both the vanadium pentoxide xerogel and in the nanocomposite are measured using the galvanostatic intermittent titration technique (GITT), and a value of 1 x 10(-12) cm(2) s (-1) was determined for both materials. Combination of these results with electrochemical impedance spectroscopy (EIS) measurements shows that the nanocomposite is more electronic conductor and exhibits shorter ionic diffusion pathways than the vanadium pentoxide parent xerogel material. In situ Raman spectroscopic results on the nanocomposite unambiguously demonstrate the oxidation and reduction of the PSPAN component during redox cycling of the nanocomposite, even though the electrochemical signature of the PSPAN is obscured by that of the vanadium pentoxide component.