Oxygen reduction at the interface of nonstoichiometric fluoride single crystals with metal electrodes

Voltammetric study of PrF3:Sr2+ and NdF3:Ba2+ solid electrolytes

“…2). It was found earlier that the oxygen reduction reaction is more eas ily realized in cells with CeF 3 :Sr 2+ than in cells with nonstoichiometric lanthanum fluorides (LaF 3 :Eu 2+ or LaF 3 :Sr 2+ ) [8]. The anodic potential sweep from ⎯0.6 V (v = 0.05 V/s) educed the anodic current peak at E PA = 1.05 V (Fig.…”

“…Earlier, it was found in experi ments with single crystals of lanthanum and cerium fluorides that such treatment allows renovating the solid electrolyte surface and providing reproducibility of results of studying the processes both with partici pation of FCSE fluoride ions at the two-phase inter face [4,5] and with participation of gaseous oxygen at the three-phase interface [7,8]. The treatment qual ity was controlled on the basis of the linear depen dence in the I,E curve of the symmetrical cell of The choice of the working voltage range is limited by the reduction potentials of cations of the rigid fluo ride sublattice [14]: …”

“…Therefore, GOR occurs in the absence of interface activation and is accompanied by appear ance of mobile oxygen forms. (Let us point out that the oxygen reduction reaction at the interface with the lanthanum fluoride single crystal with most metal electrodes [8] appeared after anodic activation of the contact.) An increase in the potential sweep rate to v = 0.02 V/s (Fig.…”

“…Efficiency of FCSE application depends on the reactivity of these boundaries. Studies of electrochemical properties of nonstoichiometric lanthanum and cerium fluorides contacting with metallic electrodes showed [4][5][6][7][8] that as dependent on the electrode nature and polarization conditions, either reactions of mobile fluoride ions in fluorideconducting FCSE electrolytes at the two-phase inter face [4,5] or reactions with participation of gaseous oxygen at the three-phase interface [6][7][8] are real ized. Solid-phase cells with neodymium or praseody mium fluorides with respect to their reactivity were not considered, though transport properties of these uni polar fluoride-ion conductors [9,10] point to the pos sible prospects of their application in various devices.…”