Mark R. Bailey

Structural Variation in the γ/β-MnO2 Series and Its Influence on Cathodic Cyclability

Electrolytic manganese dioxide (EMD) remains a prominent cathode material in alkaline battery cell s due to its low production costs, low toxicity, and excelle nt performance under low and moderate discharge rates. EMD is known to have the γ-MnO2 structure, built up of edgeand corner-sharing [MnO 6] octahedra in a manner consistent with a random microscopic intergrowth of the pyrolusite (1×1) and ramsdellite (2×1) forms of manganese dioxide [1, 2]. Other key features associ ated with the γ-MnO2 structure include microtwinning, cation vacancies, lower valent manganese cations (Mn ), and structural water present as protons.