TY - JOUR
T1 - Reflection mode XAFS at the Ti K-edge of lithium intercalated TiO 2 electrodes
AU - Lützenkirchen-Hecht, D.
AU - Wagemaker, M.
AU - Van Well, A. A.
AU - Frahm, R.
PY - 2005/12/1
Y1 - 2005/12/1
N2 - Lithium intercalation and deintercalation in crystalline TiO 2-electrodes (rutile and anatase modifications) was investigated ex situ using grazing incidence reflection mode x-ray absorption spectroscopy in a specialized cell which permits the removal of the electrolyte and the subsequent measurement of grazing incidence x-ray absorption spectra under a protecting noble gas atmosphere. Small changes observed in near edge x-ray absorption spectra indicated that the Ti4+ ions are reduced by the electrochemical lithiation, depending on the TiO2 modification, Ti3.5+ states as well as Ti3+ states are observed for rutile and anatase, respectively. Angle dependent experiments reveal that the intercalation is not complete for rutile, while anatase seems to be fully intercalated. In addition, a certain amount of Li remains in the anatase electrode after a complete intercalation - deintercalation cycle. The results suggest that Li-ions are generally accumulated at the electrode/electrolyte interface during both intercalation and deintercalation.
AB - Lithium intercalation and deintercalation in crystalline TiO 2-electrodes (rutile and anatase modifications) was investigated ex situ using grazing incidence reflection mode x-ray absorption spectroscopy in a specialized cell which permits the removal of the electrolyte and the subsequent measurement of grazing incidence x-ray absorption spectra under a protecting noble gas atmosphere. Small changes observed in near edge x-ray absorption spectra indicated that the Ti4+ ions are reduced by the electrochemical lithiation, depending on the TiO2 modification, Ti3.5+ states as well as Ti3+ states are observed for rutile and anatase, respectively. Angle dependent experiments reveal that the intercalation is not complete for rutile, while anatase seems to be fully intercalated. In addition, a certain amount of Li remains in the anatase electrode after a complete intercalation - deintercalation cycle. The results suggest that Li-ions are generally accumulated at the electrode/electrolyte interface during both intercalation and deintercalation.
UR - http://www.scopus.com/inward/record.url?scp=42149088884&partnerID=8YFLogxK
U2 - 10.1238/Physica.Topical.115a00390
DO - 10.1238/Physica.Topical.115a00390
M3 - Conference article
AN - SCOPUS:42149088884
SN - 0281-1847
VL - T115
SP - 390
EP - 392
JO - Physica Scripta T
JF - Physica Scripta T
T2 - 12th X-ray Absorption Fine Structure International Conference, XAFS12
Y2 - 23 June 2003 through 27 June 2003
ER -