Interpretation of variations of jump diffusion coefficient of lithium intercalated into amorphous WO3 electrochromic films

We report a series of electrochemical analysis of homogeneous a-LixWO3 films of 400 nm thickness prepared by electron beam evaporation technique. Self-diffusion coefficient D-J was analyzed combining measurements of the chemical capacitance, C-ch, and chemical diffusion coefficient, D,h, concluding that the barrier height involved in ion hopping increases similar to 150 meV within the range of lithium insertion level 0.001 < x < 0.3. The observed dependences C(ch)alphax(a) (a approximate to 0.65) and D(J)alphax(-c) (c approximate to 1.25) suggest that the energy changes governing charge storage and hopping are predominantly determined by the interaction energy of intercalant ions with the host glass. (C) 2004 Elsevier B.V. All rights reserved.