In this work the role of TiO2 in improving cathode performance has been investigated through the use of electrode imaging, porosity changes, electrochemical characterisation and changes in the chemical composition of constituent gamma-MnO2 particles. Time-of-flight secondary ion mass spectrometry studies revealed that TiO2 is mobile in the electrolyte and associates itself with the porous gamma-MnO2 surface. This association gives rise to improved electrode performance by allowing electron/proton pairs tomore easily (de) intercalate into the MnO2 structure. Depth profiling confirmed that upon cycling surface TiO2 becomes incorporated into the bulk gamma-MnO2 structure inhibiting proton diffusion. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.080202jes] All rights reserved.