Surface modification enhances the bulk proton conductivity of Prussian blue

Surface-modified Prussian blue shows 102 times higher bulk proton conductivity (0.018 S cm-1) than that of unmodified Prussian blue. This enhancement is attributed to the monolayer adsorption of Na4[Fe(CN)6] on the nanoparticle surface, which reduces the surface resistance. Surface modification is an effective strategy for improving bulk proton conductivity.