The cyclability of manganese dioxide samples with a wide range of initial properties has been investigated using electrochemical methods. Cycling revealed that a common change occurs in all materials irrespective of initial properties, with the discharge behaviour standardised by the tenth cycle. Modeling of the discharge behaviour revealed the steady decline in the capacity with cycling can primarily be assigned to lower potential pyrolusite domains. Furthermore, an examination of chemically reduced and re-oxidised gamma-MnO2 revealed an irreversible expansion of the gamma-MnO2 lattice upon reduction arising from localised buckling of the oxygen framework. (C) 2011 Elsevier Ltd. All rights reserved.