Lithium ion insertion in nanoporous anatase TiO2 studied with RIXS

Lithium insertion into nanoporous anatase TiO2 electrodes has been studied using resonant inelastic soft-x-ray scattering spectroscopy (RIXS). We have measured Ti 2p absorption, L-2,L-3-emission and resonant inelastic scattering spectra of pristine anatase TiO2 and Li inserted TiO2. Inelastic scattering features in RIXS spectra of pristine TiO2 are assigned to charge-transfer excitations. Low energy-loss features for Li inserted TiO2 electrodes, appearing within t(2g) bands, due to d-d excitations, indicate the presence of Ti3+ states. The experimental observations suggest strong electron correlation in anatase TiO2 introduced by the Li-insertion. (C) 2003 American Institute of Physics.