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.
|Number of pages||3|
|Journal||Physica Scripta T|
|Publication status||Published - 1 Dec 2005|
|Event||12th X-ray Absorption Fine Structure International Conference, XAFS12 - Malmo, Sweden|
Duration: 23 Jun 2003 → 27 Jun 2003