This paper describes-research to understand the relationships between materials, microstructure, and performance for primary alkaline battery cathodes composed primarily of electrolytic manganese dioxide (EMD). Specifically, the effect of various carbon additives on electronic transport within cathodes was investigated. Of the various carbon additives investigated, TIMCAL BNB90 was the best performer and graphene nanopowder was the next best. These additives had the lowest Scott density and highest BET surface area of the tested additives, and exhibited well-connected and elongated carbon pathways in SEM/FIB cross sections. Additionally, this work shows a decrease in electronic conductivity for the porous cathode in the presence of KOH electrolyte. The two top-performing cathodes, when wet with concentrated KOH had a conductivity that was about 30% below that of the dry conductivity. (C) 2014 The Electrochemical Society. All rights reserved.