The structure and ordering of ε-MnO2

Chang Hoon Kim, Zentaro Akase, Lichun Zhang, Arthur H. Heuer, Aron E. Newman, Paula J. Hughes

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76 Citations (Scopus)


The presence of ε-MnO2 as a major component of electrolytic manganese dioxide (EMD) has been demonstrated by a combined X-ray diffraction/transmission electron microscopy (TEM) study. ε-MnO2 usually has a partially ordered defect NiAs structure containing 50% cation vacancies; these vacancies can be fully ordered by a low temperature (200 °C) heat treatment to form a pseudohexagonal but monoclinic superlattice. Numerous fine-scale anti-phase domain boundaries are present in ordered ε-MnO2 and cause extensive peak broadening and a massive shift of a very intense, 0.37 nm superlattice peak. This suggests a radically different explanation of the ubiquitous, very broad ∼0.42 nm peak (∼21-22° 2θ, CuKα radiation) in EMDs, which heretofore has been attributed to Ramsdellite containing numerous planar defects. This work confirms the multi-phase model of equiaxed EMDs proposed by Heuer et al. [ITE Lett. 1(6) (2000) B50; Proc. Seventh Int. Symp. Adv. Phys. Fields 92 (2001)], rather than the defective single-phase model of Chabre and Pannetier [Prog. Solid State Chem. 23 (1995) 1] and Bowden et al. [ITE Lett. 4(1) (2003) B1].

Original languageEnglish
Pages (from-to)753-774
Number of pages22
JournalJournal of Solid State Chemistry
Issue number3
Publication statusPublished - 2006 Mar


  • Alkaline batteries
  • Manganese dioxide
  • Transmission electron microscopy
  • X-ray diffraction


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