X-ray absorption fine structure of V(2)O(5) and Li(x)V(2)O(5).
Vanadium K-edge XAFS measurements of five compounds were carried out. The compounds studied were crystalline V(2)O(5) and four types of Li(x)V(2)O(5) with different insertion levels x, which show different EMFs (2.0-3.4 V). The EXAFS data analysis shows no remarkable difference in the V-O distances in the five compounds, showing that the structure of the VO(5) square pyramids changes only slightly as lithium atoms are intercalated into the V(2)O(5). In the XANES spectra, three peaks are observed for crystalline V(2)O(5) and Li(x)V(2)O(5) (3.4 V). When the EMF is decreased, the intensity difference between the first and second peaks disappears and the third peak shifts to lower energy. The XANES data were analysed using full multiple-scattering calculations. In the calculated spectra the intensity of the first peak increases as the V(2)O(5) intercalates lithium atoms.
Yiwata
N
N
Ricoh Research and Development Center, 16-1 Shinei-cho, Tsuzuki-ku, Yokohama 224, Japan.
Watada
A
A
Yamamuro
T
T
Hayashi
Y
Y
Ohsawa
T
T
Fujikawa
T
T
Tani
K
K