“…Proton must overcome these energy barriers to move through the lattice, leading to slower diffusion and making the process less favorable. However, it is important to note that the expansion observed in both strain cases is consistent with the formation of −OH bonds as shown in Figure c (Supporting Information Figure S7b) and the appearance of larger Mn 2+ ions (ionic radii of 0.80 Å for Mn 2+ , 0.66 Å for Mn 3+ , and 0.60 Å for Mn 4+ ) …”