Anders Henningsson

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, L2,3-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 t2g 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.

Electronic structure of electrochemically Li-inserted TiO2 studied with synchrotron radiation electron spectroscopies

The electronic properties of TiO2 and electrochemically Li-inserted TiO2 have been studied using synchrotron radiation photoelectron spectroscopy and x-ray absorption spectroscopy (XAS) in conjunction with resonant photoelectron spectroscopy. Core level (Ti 2p) and valence level spectra show the presence of Ti3+ states in LixTiO2. The x values determined from core level peak intensities were found to be directly correlated to the inserted amount of Li+ determined electrochemically. The x-dependent width of the Ti 2p peaks is consistent with a two-phase regime at intermediate x values. Resonant photoelectron spectroscopy at the Ti 2p edge was performed for TiO2 and Li0.5TiO2 to delineate the Ti4+ and Ti3+ contributions to the XAS spectrum.

Li insertion in thin film anatase TiO2: Identification of a two-phase regime with photoelectron spectroscopy

Li insertion in thin film anatase TiO2: Identification of a two-phase regime with photoelectron spectroscopy

Redox properties of nanoporous TiO2 (anatase) surface modified with phosphotungstic acid

Nanostructured anatase TiO2 electrodes surface modified with inorg. metal oxide clusters, i.e., phosphotungstic acid (PWA), was studied by XPS and spectroelectrochem. The surface modifiers were electroactive and could be addressed reversibly by changing the applied bias. The formation of new states in the electronic structure of TiO2 and the PWA was monitored by XPS using a novel prepn. technique. The coloration efficiency of the deposit was about 20 cm2/C. Prolonged electrochem. cycling degraded the elec. contact between the PWA and the TiO2 surface.

Proton insertion in polycrystalline WO3 studied with electron spectroscopy and semi-empirical calculations

Proton insertion in polycrystalline WO3 studied with electron spectroscopy and semi-empirical calculations