The electronic structure change during the reversible Li-ion storage reaction in a bimetallic MnFe-Prussian blue analogue (LixK 0.14Mn1.43[Fe(CN)6]•6H2O) was investigated by soft x-ray absorption spectroscopy. The Mn L2,3-edge spectra revealed the unchanged Mn2+ high-spin state regardless of Li-ion concentration (x). On the other hand, the Fe L2,3-edge spectra clearly revealed a reversible redox behavior as Fe3+Fe2+ states with Li-ion insertion/extraction. Experimental findings suggested strong metal-to-ligand charge transfer in conjunction with the ligand-to-metal one. The resulting charge delocalization between the Fe and CN is considered to contribute to the high reversibility of the Li-ion storage process.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2011 Jul 14|