화학공학소재연구정보센터
Electrochimica Acta, Vol.46, No.13-14, 2263-2268, 2001
Insertion of lithium in vanadium and mixed vanadium-titanium oxide films
Numerous authors have suggested the use of vanadium-titanium mixed oxides as counter-electrodes for lithium conducting electrochromic devices. In this paper insertion of Li in sol-gel made (V2O5),-(TiO2)(1-x) films with x values in the range 0.5-1 were electrochemically studied by coulometric titration, cyclic voltammetry and electrochemical impedance spectroscopy (EIS). Raman spectroscopy was also performed on these films and has shown that the vanadium oxide films are well crystallised. TiO2 containing films are totally amorphous and consequently the absence of gamma -V2O5 phase allows the insertion beyond 1 Li per oxide mole in the films. The lithium diffusion in TiO2 containing films could be explained by the participation of the titanium through the V-O-Ti groups. The decrease of the diffusion rate observed on EIS data is probably due to the difference between the V-O and Ti-O bonds and their respective numbers.