Proton diffusion in [(NH4)1−xRbx]3H(SO4)2 (0 < x < 1) was studied by means of 1H

spin-lattice relaxation times, T1. The relaxation times were measured at

200.13MHz in the range of 296–490K and at 19.65MHz in the range of 300–470K.

In the high-temperature phase (phase I), translational diffusion of the acidic protons

relaxes both the acidic protons and the ammonium protons. Spin diffusion averages

the relaxation rate of the two kinds of protons, whereas proton exchange between

them were slow. The spin-lattice relaxation times in phase I were analyzed

theoretically, and parameters of proton diffusion were obtained. The mean

residence time of the acidic protons increases with increase in x for

[(NH4)1−xRbx]3H(SO4)2 (0≤x≤0.54). Rb3H(SO4)2 did not follow this trend. The

results of NMR well explain the macroscopic proton conductivity.

Proton Diffusion in the Superprotonic Phase of [(NH4)1−xRbx]3H(SO4)2 as Studied

by 1H Spin-Lattice Relaxation. H.Omi, K.Suzuki, S.Hayashi: Solid State Ionics,

2009, 180[9-10], 667-72