In Situ X‐Ray Absorption Fine Structure Studies of a Manganese Dioxide Electrode in a Rechargeable MnO2 / Zn Alkaline Battery Environment

Electronic and structural aspects of a electrode in a rechargeable battery environment have been investigated by in situ Mn K‐edge x‐ray absorption fine structure (XAFS). The relative amplitudes of the three major Fourier transform shells of the extended XAFS function of the rechargeable electrode in the undischarged state were similar to those found for ramsdellite, a polymorph with substantial comer‐sharing linkages among the basic octahedral units. The analyses of the background‐subtracted pre‐edge peaks and absorption edge regions for the nominally discharged electrode were consistent with as being the predominant constituent species, rather than a mixture of and sites. Furthermore, careful inspection of both the x‐ray absorption near edge structure and EXAFS indicated that the full recharge of , which had been previously discharged either by one or two equivalent electrons, generates a material with decreased corner‐sharing linkages compared to the original undischarged .