Abstract
Thermal and transport properties, as well as spectral characteristics of Rb5H7(PO4)4, have been investigated by several methods. It was shown that Rb5H7(PO4)4 undergoes a reversible phase transition at Tp ~ 237 °С. However, the interval of the high-temperature phase stability is quite narrow, about 15 °С. The initial dehydration event in Rb5H7(PO4)4 occurs at 200 °С. The conductivity measurements were performed under highly humidified conditions (PH2O ≈ 0.56 atm.) to suppress dehydration of the title salt. The phase transition leads to the sharp increase of proton conductivity up to 10−2 S/cm. The reverse transition goes slowly with significant hysteresis on cooling. Thus, the superprotonic conductivity of Rb5H7(PO4)4 was determined. The possibility of superionic phase stabilization by humidification was shown. The IR- and Raman spectra have been recorded at room temperature and discussed in relation to the crystal structure.
Original language | English |
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Pages (from-to) | 551-557 |
Number of pages | 7 |
Journal | Ionics |
Volume | 25 |
Issue number | 2 |
DOIs | |
Publication status | Published - 5 Feb 2019 |
Keywords
- Ac-impedance spectroscopy
- Proton conductivity
- RbH(PO)
- Superprotonic conductors
- Thermal analysis
- RBH2PO4
- HIGH-TEMPERATURE
- CSH2PO4
- Rb5H7(PO4)(4)
- COMPOSITE
- DEHYDRATION BEHAVIOR