SOLIDIONIC

Fig. 2-1 Conductivity of proton-conducting hydroxides family

The temperature run of conductivities of individual hydroxides (LiOH, NaOH, KOH), crystalline hydrates (NaOH.H2O, KOH.H2O, KOH.2H2O) and eutectics (KOH+KOH.H2O, KOH+NaOH, LiOH+1.5NaOH). All data have obtained and published by Baikov et al, with exeption LiOH. See also paper on this site.

Fig. 2-2 Self diffusion of proton (hydrogen species) in hydroxide family

The temperature run of self-diffusion coefficients of hydrogen in individual hydroxides (LiOH, NaOH, KOH), crystalline hydrates (NaOH.H2O, KOH.H2O), and eutectics (KOH+KOH.H2O, KOH+NaOH, LiOH+1.5NaOH). All data have obtained and published by Baikov et al. For comparison the diffusion coefficients of these compounds calculated by Nernst-Einstein formula (without any correlation factors) are presented. For the hydrate of KOH there are the uncertainty due to the part of mobile protons. The probable reason for remarkable Haven ratio from unit is discussed in our papers included in this site.

Fig. 2-3 Phase transition into superprotonic state of anhydrous eutectic

Calorimetric study of hydroxide solid protonic conductors has revealed the remarkable phase transition in eutectics, but not in hydrates. DSC spectra for eutectic NaOH+KOH around 360 K coincides with strong effect at measurements of conductivity (2-1-) and also in some physicochemical properties. It seems that the DSC peaks could be decomposed as pair of ones. Maybe it is manifestation of self-assembled micro-heterogeneity of the solid eutectic. Lines on this figure mean: A-heating, C(black)-cooling; dashed B and C are one of components, green line second component at decomposition of experimental DSC curve; both “ra” calculated sum of curves, obtained at theoretical decomposition. The pair of straight lines indicate the shift of peaks (minima –black line and maxima-line+symbol) at different rate of temperature scanning. The scale for these rates on the Y-axis in K per minute.

Fig. 2-4 Kinetics of isotopic exchange between molecular hydrogen and solid protonic conductors

Here as example the procedure of direct exchange H/D are presented to get the solid sample of constant geometric form but different isotopic composition. The difference of deuterium part in equilibrium state is due to enough high magnitude of isotope separation in this system (~1.5, deuterium concentrate in solids, Baikov(1980)). Simultaneously this data is the evidence for the ability of solid protonic conductors to activate the molecular hydrogen without any catalysts.