Figure (a) shows representative elementary volume (REV) analysis using the tortuosity factor obtained in orthogonal directions using the MATLAB application TauFactor . The results show that a REV could be obtained at 90% of total electrode volume, highlighting the extent of heterogeneity present in the electrode. Hence, to analyse the effect of heterogeneity on the electrochemical performance, REV sampling is not viable. Therefore, a multiple subsampling approach was adopted where 300 µm × 300 µm samples, cut through the entire thickness of the electrode, were selected from the various points as shown in Figure . This approach allows for the evaluation of the effect of heterogeneities on the performance, considering the coverage of the subvolume locations, and minimises the computational expense of the electrochemical analysis. The subvolumes were selected to mostly avoid the large void space displayed as a crack in the electrode surface. Table shows the phase volume fraction present in each subvolume, highlighting the variation of CBD, sulfur and electrolyte volume present. As discussed in the previous section, variations in the phase volumes will affect the Li + ion flux and the localised discharge performance. Electrolyte to sulfur ratio (E/S ratio) is the critical parameter that defines the sulfur dissolution process , the initial discharge capacity, and the cell durability . It should be noted here that calculated E/S ratios are based entirely on the local microstructure and assume zero excess electrolyte -in reality, Li-S cells will be flooded with electrolyte and likely have much higher E/S ratios for the cell as a whole, and so the reported values here are all much lower than cell-level E/S ratios.