Influence of the crystallinity on the Li+ intercalation process in Nb2O5 films |
| |
Authors: | Adriane V Rosario Ernesto C Pereira |
| |
Institution: | (1) Laboratório Interdisciplinar de Eletroquímica e Cerâmica, Centro para o Desenvolvimento de Materiais Cerâmicos, Departamento de Química, Universidade Federal de São Carlos, CP: 676, 13560-970 São Carlos, Brazil |
| |
Abstract: | Nb2O5 thin films were prepared by the Pechini method. The effect of the film crystallinity on the electrochemical and electrochromic properties was investigated. A relationship between the crystalline structure and the Li+ intercalation/extraction process, stability and kinetics was observed. A significant decrease in the electrochemical response was observed as a function of the number of cycles for films treated at 400 and 450 °C. However, as the calcination temperature increases this effect disappears. XRD studies shown that at 400 °C, the material is amorphous, evolving to orthorhombic phase. The transmittance variation as well as the coloration efficiency increases as the temperature is increased. In the initial cycles the intercalation charge is higher for the amorphous oxide than for the orthorhombic phase. However, the variation in the optical density is small. On the other hand, the charge of the orthorhombic phase oxide does not change. These results suggest that there are two different processes associated with Li+ intercalation, but only one of them leads to the coloration process. |
| |
Keywords: | Nb2O5 Electrochromism Li+ intercalation Pechini method |
本文献已被 SpringerLink 等数据库收录! |
|