Lithium ion insertion in nanoporous anatase TiO_2 studied with RIXS

摘要

Lithium insertion into nanoporous anatase TiO_2 electrodes has been studied using resonant inelastic soft-x-ray scattering spectroscopy (RIXS). We have measured Ti 2p absorption, L_2,3-emission and resonant inelastic scattering spectra of pristine anatase TiO_2 and Li inserted TiO_2. Inelastic scattering features in RIXS spectra of pristine TiO_2 are assigned to charge-transfer excitations. Low energy-loss features for Li inserted TiO_2 electrodes, aoppearing within t_2g bands, due to d-d excitations, indicate the presence of Ti~(3+) states. The experimental observations suggest strong electron correlation in anatase TiO_2 introduced by the Li-insertion.