Lithium intercalation properties in manganese-iron Prussian blue analogues

We investigated the electronic states and structural properties of LixMn[Fe(CN)(6)](0.83)center dot 3.5H(2)O, and LixMn[Fe(CN)(6)](0.87)center dot 2.6H(2)O, which have different amount of [Fe(CN) 6] vacancies. X-ray absorption spectra near the Fe and Mn K-edges revealed that the Li intercalation/deintercalation process is two-electron reaction, i.e. Mn-II-NC-Fe-II, Mn-II-NC-Fe-III, and Mn-III-NC-Fe-III. The crystal structure of LixMn[Fe(CN)(6)](0.83)center dot 3.5H(2)O remains cubic and single phase throughout the Li intercalation/deintercalation process. The crystal structure of LixMn[Fe(CN)(6)](0.87)center dot 2.6H(2)O is also cubic, while phase separation of Li+-rich phase and Li+-poor phase was observed during the Mn-II/Mn-III reduction/oxidation process.