Li diffusion and electrochromism in amorphous and crystalline vanadium oxide thin film electrodes

Journal of the Brazilian Chemical Society

Scarminio, Jair¹  Universidade Estadual de Campinas, Campinas, Brazil¹  Urbano, Alexandre¹  Gelamo, Rogério V.¹  Catarini, Paulo R.¹  Rouxinol, Francisco P.¹  Moraes, Mário A. Bica de¹  Universidade Estadual de Londrina, Londrina, Brazil¹ 

关键词: vanadium oxide film;    chronopotentiometric;    DC measurements;   

DOI  :  10.1590/S0103-50532008000400025

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

Amorphous vanadium oxide films were synthesized onto ITO-coated glass substrates by the hot filament metal oxide deposition technique. The as-deposited samples were heat-treated in an argon atmosphere. X-ray diffraction analysis revealed that the films treated at 200 and 300 ºC were still amorphous, while those treated at 400 and 500 ºC were crystalline, with a V2O5 structure. All electrodes were electrochemically reversible for Li+ intercalation, exhibiting the electrochromic effect, observed from optical transmittance measurements at 632.8 nm. The Li-diffusion coefficient, DC, was measured by the galvanostatic intermittent titration technique (GITT) as function of the inserted charge. For the crystalline films it was observed that the optical absorbance and the DC increase with increasing Li insertion in the single-phase regions of crystalline LixV2O5 and decrease in the two-phase regions. For the latter, an effective DC was considered. The presence of other vanadium oxides mixed to the V2O5 matrix was inferred for the crystalline films from the chronopotentiometric and DC measurements.

【 授权许可】

Unknown