Adding nanoparticle fillers is a potential route to enhance room temperature ionic conductivity of solid polymer electrolytes. In this work, we use molecular dynamics simulation to elucidate the role of nano-scale filler size and shape anionic conductivity. Our key conclusions are that the addition of nanofillers can affect the salt dissociation, lithium-ion mobility, and the dynamics of polymer chains. The repulsive nanofillers of different sizes appear to suppress ion-cluster formation and enhance lithium ion mobility. Smaller size nanofillers are found to be comparatively more effective in increasing the mobility of lithium ions while shape effects appear to be insignificant. (C) 2014 Elsevier B.V. All rights reserved.