Polarized light study of the CsHSO4 and CsDSO4 superprotonic crystals

Sulfonated hydrocarbon membranes for medium-temperature and low-humidity proton exchange membrane fuel cells (PEMFCs)

“…These additives exhibit intrinsic proton conduction capabilities over a wide range of temperatures and humidities ( Fig. 46(a)) [205][206][207][208][209][210][211][212][213][214]. Their proton conductivity usually becomes high as the humidity increases.…”

“…For improved dispersion of the additives, sonication is sometimes employed after mixing. Most of the sulfonated polymer matrices used in this approach have a proton conductivity that is sufficiently high for PEMFC applications, but their excessive water swelling and high fuel permeability (H 2 and O 2 ) must be reduced via a combination with inorganic additives [205][206][207][208][209][210][211][212][213][214]. Unfortunately, it is very hard to avoid heterogeneity in both the size of the inorganic agglomerates and the dispersion state with the direct mixing method.…”

Ion conduction in proton- and related defect (super) ionic conductors: Mechanical, electronic and structure parameters

“…For mobile ion-type SICs, the B-curve is drawn with G = 10.8 and H = 0.85. SPCs and Li-ion conductors are also plotted on B-curve within a small scatter [46][47][48][49][50][51][52][53][54][55][56]. Impurity H + -ion [38,57,58] and O-ion defect conductors [5][6][7]17,59,60] are plotted on the A-curve that is drawn with G = 9.8 and H = 0.55.…”

Phase behaviour of the solid proton conductor CsHSO4

“…According to these authors, the reverse II → III transition could also be induced at room temperature by grinding the preheated CHS in a mortar [15]. In a polarized light study of CHS crystals, Kirpichnikova et al [16] reported a substantial decrease of crystal quality, and partial decomposition of the substance accompanied the III → II transition at 100 • C. The surface of the sample was covered with dark spots of a segregated substance. A subsequent measurement performed on the same specimen kept for two days at room temperature revealed that the temperature of the III → II transition decreased to 57 • C.…”

“…When the appearance of the CHS superprotonic plastic phase I is monitored by a polarization microscope, colour patterns unusual for monocrystals are observed [24]. Moreover, Kirpichnikova et al [16] also observed this phenomenon in the superprotonicconducting phase of CsDSO 4 (CDS) crystals, but, upon cooling below 141 • C, a wedge-shaped ferroelastic domain structure was observed to grow through the motion of a phase front, the wedge-shaped structure became smaller, and the bright colour of the sample vanished [16]. Additionally, these authors observed that the II → I transition of CHS was also accompanied by a surface partial decomposition [16].…”