Electron delocalization in cyanide-bridged coordination polymer electrodes for Li-ion batteries studied by soft x-ray absorption spectroscopy

Daisuke Asakura, Masashi Okubo, Yoshifumi Mizuno, Tetsuichi Kudo, Haoshen Zhou, Kenta Amemiya, Frank M. F. de Groot, Jeng-Lung Chen, Wei-Cheng Wang, Per-Anders Glans, Chinglin Chang, Jinghua Guo (+1 others)
2011 Physical Review B  
The electronic structure change during the reversible Li-ion storage reaction in a bimetallic MnFe-Prussian blue analogue (Li x K 0.14 Mn 1.43 [Fe(CN) 6 ] · 6H 2 O) was investigated by soft x-ray absorption spectroscopy. The Mn L 2,3 -edge spectra revealed the unchanged Mn 2+ high-spin state regardless of Li-ion concentration (x). On the other hand, the Fe L 2,3 -edge spectra clearly revealed a reversible redox behavior as Fe 3+ ↔ Fe 2+ states with Li-ion insertion/extraction. Experimental
more » ... ngs 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.
doi:10.1103/physrevb.84.045117 fatcat:l3k4mreq2fdrtnrmxc7danx7mq