Highly decoupled ionic and protonic solid electrolyte systems, in relation to other relaxing systems and their energy landscapes

With an interest in correlating the properties of ions in ionic glasses with other decoupled motion phenomena in glasses, we have analyzed several cases involving different modes of motion, and different mobile particles, for their similarities and distinctions, and then add new cases with protons as the mobile species. The deviations from Arrhenius relaxation kinetics, that are used to characterize liquids by their fragilities, are found also in the behavior of the non-liquid states. On appropriate temperature scaling, these deviations provide patterns with common features, but also distinctions due to the effective confinement stemming from the non-liquid states. The different degrees of fragility in the (ionic) subsystems of superionic glasses, seem to be related to the weak ‘mobile species glass transitions’ that can be detected at lower temperatures. Such behavior suggests the existence of an ‘energy landscape’ for the mobile sub-system, inviting the possibility of annealing effects within the subsystem. Examples of de-coupled ‘dry’ proton conductivity, up to 10−2 S cm−1 at 100 °C, are provided. We give a section to reporting these new liquid and plastic crystal systems which involve large cations and protonated anions, and represent improvements on the CsHSO4 type proton conductor.