Optical and electrochemical properties of vanadium pentoxide gel thin films

Optical and electrochemical properties of vanadium pentoxide (V2O5) films prepared by sol-gel method from organic and inorganic precursors were studied. The organic gel was obtained by hydrolysis and polycondensation of vanadium isopropoxide dissolved in isopropanol. The inorganic gel was prepared from aqueous solution of sodium vanadate. Lithium insertion in LiyV2O5 films (0<y less than or equal to 2.0) was investigated by cyclic voltammetry and electrochemical potential spectroscopy, showing good reversibility up to y similar to 2.0 and structure transitions from alpha phase to epsilon phase and delta phase in the range 0<y less than or equal to 1.0. Highest values for chemical diffusion coefficient were about 3x10(-10) cm(2)/s at y similar to 0.8, as determined from complex impedance measurements. (C) 1996 American Institute of Physics.