From the XPDF analysis presented above, we deduce that sodiation within the slope region occurs over a broad distribution of storage sites that characterize sodium adsorption and the corresponding changes in the HC structure. These storage sites are filled as the electrochemical reactions proceed, with certain chemical environments being more energetically favorable and, consequently, manifesting earlier in the sequence. The slope in the potential-capacity curve reflects the contribution of various sites to the overall sodium storage, with the first and steeper gradient indicative of adsorption at surface defect sites (Figure and Figure ) and the subsequent and shallower gradient representing sodium adsorption at intralayer defect sites, e.g. the defect-assisted intercalation process described above. It is noteworthy that while some high-binding energy storage sites may initially show greater sodium uptake due to their higher reactivity and thermodynamically favorable nature, desorption from these sites is consequently less favorable, as observed by the decrease in the slope capacity region during the second cycle (Figures ) and S1). This emphasizes the importance of balancing thermodynamic and kinetic considerations when designing sodium storage systems.