STUDY OF THE PHASE COMPOSITION AND ELECTROTRANSPORT PROPERTIES OF THE SYSTEMS BASED ON MONOAND DISUBSTITUTED PHOSPHATES OF CESIUM AND RUBIDIUM
V. G. PONOMAREVA1,2, I. N. BAGRYANTSEVA1,2, A. A. GAYDAMAKA1,2
1Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
Keywords: одно- и двузамещенные фосфаты цезия и рубидия, RbH(PO), Cs(HPO)(HPO)•2HO, протонная проводимость, твердые электролиты, mono and disubstituted phosphates of cesium and rubidium, RbH(PO), Cs(HPO)(HPO)·2HO, proton conductivity, solid electrolytes
Pages: 238-245
Abstract
A detailed study of the phase composition, transport and thermodynamic characteristics of the systems based on mono- and disubstituted phosphates of cesium and rubidium (1-x)MH2PO4-xM2HPO4·2H2O (M=Rb, Cs) within a wide range of compositions (0≤х≤1) was performed. For these systems, new phases were identified, and their transport and thermal characteristics were determined. For cesium compounds, the new Cs3(H2PO4)(HPO4)·2H2O salt was found at x = 0.5. Cs3(H2PO4)(HPO4)·2H2O single crystals were synthesised and their crystal structure was determined for the first time, as well as thermodynamic characteristics and proton conductivity. It was shown that the compound does not have a superionic phase transition. In the rubidium system, a monophase region at x = 0.25 was found, corresponding to Rb5H7(PO4)4 compound. Its electrotransport and thermodynamic properties were investigated. It was shown that Rb5H7(PO4)4 has a phase transition at 252°C to the high-temperature phase, which is characterised by high proton conductivity. For other mole fraction x values for (1 - x)MH2PO4 / xM2HPO4•2H2O (M = Rb, Cs), binary phase regions are realized; these two phases include the initial component, which dominates within this composition range, and the nely formed compound, which significantly affects the physicochemical properties of the system.
DOI: 10.15372/CSD2019132
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