In this equation, b represents the slope is directly associated with the charge storage mechanism. For instance, a value of "b" equal to 0.5 suggests a diffusion-controlled process, while a value higher than 0.5 indicates a surface-controlled process. Among the different electrode materials investigated, PNZF exhibited the highest values: 0.84 for oxidation and 0.71 for reduction (Figure ). This suggests a predominantly surface-controlled process. However, the impact of mass transport by ion diffusion is still contributing to the overall performance at high scan rates .