Abstract
Caesium hydrogen sulfate (CsHSO4) and caesium dihydrogen phosphate (CsH2PO4) are solid acids that undergo superprotonic phase-transitions at about 140 and 230 °C,
respectively. As a result, the proton conductivity is increased by
several orders of magnitude. However, the practical operational
temperature range is narrow due to decomposition of the
high-conductivity phases. For CsHSO4, it is known that this window can be extended to lower temperatures by addition of carefully selected N-heterocycles.
The present work investigates if the same approach can be used to
extend the practical operating temperature range of CsH2PO4 as well. Binary mixtures of CsH2PO4 with 1,2,4-triazole, benzimidazole or imidazole were prepared by means of mechanochemical synthesis. Mixtures based on CsHSO4 were prepared as a basis for a comparative discussion. It was found that CsHSO4 formed organic-inorganic salts, while CsH2PO4 formed heterogeneous mixtures with the N-heterocycles due to its weaker acidity. At a N-heterocycle content of 30 mol%,
enhanced proton conductivity was observed for both solid acids at
temperatures below their superprotonic phase transitions.
Original language | English |
---|---|
Journal | Solid State Ionics |
Volume | 306 |
Pages (from-to) | 13-19 |
ISSN | 0167-2738 |
DOIs | |
Publication status | Published - 2017 |
Keywords
- Solid acid
- Caesium dihydrogen phosphate
- Composite
- Electrolyte
- Conductivity