We studied the discharge of a half cell model (Figure ) at C rates 0.1C and 1C, with a cut-off potential of 0.01 V. The discharge curves of the graphite/Si composite electrode are shown in Figure (a). At 0.1C, the shape of the potential curves follow the known three plateaus of the graphite OCV. However, at 1C, these plateaus disappear, along the apparent capacity loss. Under 0.1C, the discharge depth reached 96.96%, while for 1C, only 65.64% of the capacity is used. This phenomenon is attributable to the overpotentials arising from mass transfer and interface reaction limitations, as well as internal electronic resistances. Nevertheless, when compared to a traditional single AM electrode, assessing the origin of the overpotentials becomes much more intricate when considering composite electrodes with more AM phases. This is because the differences in the electrochemical properties of both phases results in an interplay between both graphite and Si, making them experience different chemical environments. Then, graphite starts to dominate, where the slope of the Si SOC curve starts to decrease. This twostage process can be further verified as shown in Figure (c), where the current contributions of each AM to the total current intersect in the middle of the discharge, therefore showing how each phase reacts at different discharge depths. There are several aspects that affect this behavior. Figure shows the average overpotentials calculated for graphite and Si, throughout the discharge process. We notice that the average value of the Si overpotential is maintained at very low values between -1.5 mV and -0.3 mV. On the contrary, graphite experiences a much larger overpotential ranging between -60 mV to -20 mV. In principle, this leads to much lower local current densities for the Si phase, when compared to graphite (Figure ). However, due to the fact that the Si particles are considered as nanosized (45 nm), given their extremely high surface area (~90000 μm 2 ), the Si phase actually accommodates rather large reaction currents. On the other side, graphite particles are much larger, and therefore their surface area is much lower (around 8400 μm 2 ), thus resulting in overall lower total currents, where graphite dominates. Looking at this process in more detail, we see that at around 25% of discharge depth, the current contribution curves intersect, and graphite starts dominating the reactions at the second stage. At this transition point, the SOC of Si and graphite is of around 0.5 and 0.1, respectively, which relates to the first plateau in the graphite OCV curve. Afterwards, the graphite OCV drops below 0.2 V and thus starts further reacting and increasing its SOC. Additionally, we can differentiate how each phase experiences the faradaic current, by calculating their respective C rates (Figure ). In fact, we can see that Si is experiencing C rates as high as 2.08 at 9% discharge depth. While the highest value for graphite reaches 1.33 at 54% discharge depth. Same for 0.1C scenario, the materials are also experiencing different C rates. This deviation from the C rate that is applied to the composite electrode as a whole, evinces the difficulties when working with electrodes where multiple AM phases coexist, and demonstrates the need of additional considerations to make in the design of efficient composite anodes.