In situ IR spectroscopy during oxidation process of cobalt Prussian blue analogues.

Cobalt Prussian blue analogues (Co-PBA; NaCo[Fe(CN)]), consisting of cyano-bridged transition metal network, -Fe-CN-Co-NC-Fe-, are promising cathode materials for Na-ion secondary batteries. In the oxidation process, oxidization of Fe and/or Co are compensated by Na deintercalation. Here, we investigated the oxidization process of three Co-PBAs by means of in situ infrared absorption (IR) spectroscopy.

Aggregation tendency of guest Fe in NaCoFeO (x < 0.1) as investigated by systematic EXAFS analysis.

In transition metal (M) compounds, the partial substitution of the host transition metal (M) to guest one (M) is effective to improve the functionality. To microscopically comprehend the substitution effect, degree of distribution of M is crucial. Here, we propose that a systematic EXAFS analysis against the M concentration can reveal the spatial distribution of M.