Proton conduction based on intracrystalline chemical reaction
Authors: G. Schuck, R.E. Lechner und K. LangerJournal-ref: Applied Physics A, 74 (2002) Suppl. 1098-1100, PDF
Abstract:
Proton conductivity in M3H(SeO4)2 crystals (M = K, Rb, Cs) is shown to be due to a dynamic disorder in the form of an intracrystalline chemical equilibrium reaction: alternation between the association of the monomers [HSeO4]1− and [SeO4]2− resulting in the dimer [H(SeO4)2]3− (H-bond formation) and the dissociation of the latter into the two monomers (H-bond breaking). By a combination of quasielastic neutron scattering and FTIR spectroscopy, reaction rates were obtained, as well as rates of proton exchange between selenate ions, leading to diffusion. The results demonstrate that this reaction plays a central role in the mechanism of proton transport in these solid-state protonic conductors.