With the ever-increasing demand for low-cost, high-performance alternative energy sources for transportation and large-scale energy storage systems, focus has been applied to the development of systems with high energy density. Amongst these, lithium sulfur (Li-S) batteries are one of the most promising candidates due to their high theoretical specific capacities (1675 mAh g -1 ); however, to date, the commercialisation of the technology has been hindered by a number of key factors which reduce the overall energy density, lifetime and rate performance of the cells . The primary challenges faced by Li-S technology include the insulating nature of elemental sulfur (electrical conductivity of 1 × 10 -30 S m -1 at room temperature) which reduces the practical sulfur loading and utilisation achievable due to the need for non-active conductive additives . While cathodes can be manufactured with an idealised morphology, the dissolution of sulfur into the electrolyte and precipitation of Li2S , and the subsequent reversal of this process, manifest in significant alterations of the cathode morphology of the electrode during cycling . This dynamic process significantly effects the distribution of sulfur after just a single operating cycle and can result in the formation of large sulfur particles or the isolation of sulfur and consequent impairment of rate performance or capacity . During prolonged cycling, these processes also increase the cell's impedance by reducing the electrochemically active surface area in the battery. To date, the vast majority of modelling work in the Li-S field has focussed on zero-and one-dimensional models which do not account for these large microstructural changes. However, to develop a more complete understanding of the behaviour of Li-S batteries, three-dimensional numerical modelling is required. These models can leverage the increasing viability of imaging techniques such as X-ray computed tomography (CT) to describe and predict the battery morphology and give an improved insights into cell operation and performance. The strength of this approach has previously been demonstrated in the Liion community with insights enabling improved design strategies for electrodes as well as in other electrochemical energy devices such as fuel cells. . The development of such models for Li-S will allow not only for improved cathode designs, but will also enable the evolution of morphology to be examined in a more rapid fashion, providing fundamental and mechanistic insights which will help accelerate the commercial relevance of Li-S cells. Li-S cathodes undergo drastic morphological changes during cycling and therefore applying 3D modelling frameworks to the various microstructures present in the system is even more critical than for relatively dimensionally stable electrodes (as in PEM fuel cells or intercalation electrodes in Li ion batteries), even though it is well known that image-based modelling can have significant benefits over volume averaged methods, even in these morphologically stable systems.