Numerical simulation is used to explore the influence of particle shape and overall porosity on the liquid phase conductivity, σ eff, inside porous networks, such as electrodes or separators used for lithium-ion batteries. Such battery components are often modelled by a power law, σ eff=ε α σ 0, which relates electrolyte bulk conductivity σ 0 and void volume fraction ε via a Bruggeman exponent α. Frequently, a value of 1.5 is assumed for α. In this work, theoretical and experimental evidence is presented to show that a Bruggeman exponent of 1.5 is often not valid for real electrodes or separator materials. It is found that only idealized morphologies, based on spherical or slightly prolate (i.e. rod-type) ellipsoids, are expected to give rise to a Bruggeman law with an exponent of about 1.3. Porous networks based on other particle morphologies such as oblate (i.e. disk-type) ellipsoids or lamellar or flaky materials increase the tortuous path for ionic conductivity and result either in a significant increase of the exponent α, or in a complete deviation from the power law. These models imply that spherical or slightly prolate ellipsoidal particles should be preferred for batteries where high-rate performance is required and that future separators could be designed with higher ionic conductivity.