Mn L2,3-edge X-ray absorption spectroscopic studies on charge-discharge mechanism of Li2MnO3

The redox reaction of Mn in Li2MnO3 was studied by X-ray absorption spectroscopy and ab initio multiplet calculation. Associated with the de-intercalation of Li-ion, small but clear spectral changes were observed in Mn-L-2,L-3 X-ray absorption near edge structure (XANES). The systematic ab initio multiplet calculations of Mn-L-2,L-3 XANES revealed that the spectral changes in the experiment could not simply be ascribed to the change of the valency from Mn4+ to Mn5+ but can be explained well by the changes of local atomic structures around Mn4+ due to the Li de-intercalation. Our results suggest that the electronic state of oxygen should change during charging in Li2MnO3. (C) 2014 AIP Publishing LLC.