In comparison, there are significantly fewer studies which take into account the heterogeneous microstructure of the cathode. The studies that consider cathode microstructure have utilised stochastically generated carbon/sulfur microstructures based on several input assumptions such as the carbon to sulfur ratio, pristine porosity and initial polysulfide concentration, amongst others . Mistry and Mukharji used a direct numerical simulation approach to evaluate the interaction between the precipitation mechanism and carbon microstructure . This study used pristine porosity, sulfur loading, and mean pore size to generate the initial cathode microstructure. The solid phase change, i.e., sulfur dissolution and polysulfide precipitation, was modelled using the assumption of dissolved sulfur content equal to the solubility limit and the surface passivation/blockage approach, respectively. The extent of precipitation and growth is defined by altering the morphology factor which controls the location for further precipitation, providing unique film-type or finger-type precipitation. The effective cathode structure was further translated into a 1D continuum electrochemical reaction model based on Kumaresan's approach to predict the discharge performance of the microstructure. This approach presents an interesting 3D+1D way to correlate the random precipitation growth (i.e., without describing the mechanism for affinity to cohesion/adhesion bonds) within the stochastically produced microstructure and the consequent effect on altering the cell performance. However, as the study is based on a stochastically developed microstructure using effective properties, it fails to elucidate the effect of localised variations in the carbon structure of electrodes that would alter the electrolyte to sulfur (E/S) ratio, pore size distributions and localised interfacial reactive surfaces. Thangavel et al. used a kinetic Monte Carlo approach on a stochastically derived C/S microstructure to analyse the effects of varying discharge rates on the performance and mesoscale deposition of Li2S on the non-reactive carbon structure in the cathode . This approach captures microstructural evolutions including alterations in porosity and the localised coverage of solid polysulfides; however, this study is based on an artificiality developed local microstructure that fails to capture the effect of heterogeneity, E/S ratios and pore size distributions of cell performance, which is crucial in defining the performance of the electrode level. This study also only accounts for the partial sulfur reduction mechanism and considered precipitation of only Li2S, ignoring the coexistence of two solid precipitation processes during discharge. The modelling studies discussed above can each be used to analyse the effect of various parameters on the overall performance of Li-S cells; however, they fail to include the effect of realistic microstructures on the localised performances. Understanding the complex, 3D nature of the electrode microstructure and the microstructure's relationship with the dynamic local conditions is critical to evaluate the effect of structural heterogeneities on the battery performance and is the key for further developments of Li-S cathodes to improve cell life, rate performance and capacity . used in-situ X-ray computed tomography (CT) to emphasise the heterogeneous nature of the C/S electrode and the evolution of electrode microstructure during cell discharge. These studies highlighted the extent of heterogeneity present in the electrode and the importance of evaluating the effect of pristine architecture on the first discharge cycle. Here, we use microstructural geometries obtained using X-ray CT as an architecture to develop a 3D model which enables the examination of the impact of localised heterogeneities at multiple discharge rates.