The diffusion for individual ions appears to be related to the hydration shell radius. Within the MD simulation trajectories, we observe that similarly charged ions may have different diffusion coefficients. For instance, the sodium ion (Na + ) diffusion is a factor 2-3 slower compared to potassium ion (K + ) (Figure ). This correlates with measures of the hydration shell radius, as measures for K + (3.31 Å) or Cl -(3.32 Å) are similar, followed by Na + (3.6 Å) and then Cu 2+ , which has a larger hydration shell (4.1 Å) . This relationship mechanistically suggests that rapid ion diffusion depends on solvating the ion within the relatively mobile water within the cell wall environment.