Retaining the high-temperature phases of Rb3H(SO4)2 and Rb5H3(SO4)4 at room temperature


  • Chatr Panithipongwut KOWALSKI Research Unit of Advanced Materials for Energy Storage, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand


Solid acids, Rb3H(SO4)2, Rb5H3(SO4)4, Phase transition, Quenching


The attempts to maintain the higher-temperature phases of Rb3H(SO4)2 and Rb5H3(SO4)4 were demonstrated in this work for the first time. The goal was to explore the possibility to utilize solid acids at lower temperatures while keeping the high-temperature phases which connects to the desirable conductivities. Enabling to do so will allow the ease of handling and thermal cycling, and the energy saving in fuel cell applications, and will allow researchers to study the high-temperature properties of solid acids at lower temperatures without the expenses for the in-situ measurements and the accessibility limitations. The four relatively simple methods, which were the oven, the active airflow, the dry ice, and the liquid nitrogen methods, were selected to compare with the natural cooling at the room temperature. The dry ice and the liquid nitrogen methods for both Rb3H(SO4)2 and Rb5H3(SO4)4 could not preserve the high-temperature structures at all. The other three methods worked poorly for Rb3H(SO4)2, but quite well for Rb5H3(SO4)4. The oven method was the best to retain one of the Rb5H3(SO4)4 structures and no evidence of the original phases formed until several days later, revealing the possibility to use and study Rb5H3(SO4)4 at lower temperatures in the future.


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E. V. Selezneva, I. P. Makarova, I. A. Malyshkina, N. D. Gavrilova, "New superprotonic crystals with dynamically disordered hydrogen bonds: Cation replacements as the alternative to temperature increase," Acto Crystallographica Section B: Structural Science, Crystal Engineering and Materials, vol. 73, no. Pt 6, pp. 1105-1113, 2017.

D. Z. Yi, S. Sanghvi, C. P. Kowalski, and S. M. Haile, "Phase behavior and superionic transport characteristics of (MxRb1-x)3

H(SeO4)2 (M = K or Cs) solid solutions," Chemistry and Materials, vol. 31, no. 23, pp. 9807-9818, 2019.

A. Ikeda, D. A. Kitchaev, and S. M. Haile, "Phase behavior and superprotonic conductivity in the Cs1-xRbxH2PO4 and Cs1-xKxH2PO4 systems," Journal of Materials Chemistry A, vol. 2, no. 1, pp. 204-214, 2014.

A. Ikeda, and S. M. Haile, "Examination of the superprotonic transition and dehydration behavior of Cs0.75Rb0.25H2PO4 by thermogravimetric and differential thermal analyses," Solid State Ionics, vol. 181, no. 3-4, pp. 193-196, 2010.

Y. K. Taninouchi, T. Uda, Y. Awakura, A. Ikeda, and S. M. Haile, "Dehydration behavior of the superprotonic conductor CsH2PO4 at moderate temperatures: 230 to 260 degrees C," Journal of Materials Chemistry, Article vol. 17, no. 30, pp. 3182-3189, 2007.

S. M. Haile, C. R. I. Chisholm, K. Sasaki, D. A. Boysen, and T. Uda, "Solid acid proton conductors: from laboratory curiosities to fuel cell electrolytes," Faraday Discussions, vol. 134, pp. 17-39, 2007.

S. Takeya, S. Hayashi, H. Fujihisa, and K. Honda, "Phase transition in a superprotonic conductor Cs2(HSO4)(H2PO4) induced by water vapor," Solid State Ionics, vol. 177, no. 15-16, pp. 1275-1279, 2006.

Y. Matsuo, J. Hatori, Y. Yoshida, K. Saito, and S. Ikehata, "Proton conductivity and spontaneous strain below superprotonic phase transition in Rb3H(SeO4)2," Solid State Ionics, vol. 176, no. 31-34, pp. 2461-2465, 2005.

Y. Matsuo, Y. Tanaka, J. Hatori, and S. Ikehata, "Proton activity and spontaneous strain of Cs3H(SeO4)2 in the phase transition at 369 K," Solid State Communications, vol. 134, no. 5, pp. 361-365, 2005.

S. M. Haile, K. D. Kreuer, and J. Maier, "Structure of Cs3(HSO4)2 (H2PO4) - a new compound with a superprotonic phase transition," Acta Crystallographica Section B-Structural Science, vol. 51, pp. 680-687, 1995.

S. M. Haile, G. Lentz, K. D. Kreuer, and J. Maier, "Superprotonic Conductivity in Cs3(HSO4)2(H2PO4)," Solid State Ionics, vol. 77, pp. 128-134, 1995.

S. M. Haile, P. M. Calkins, and D. Boysen, "Superprotonic conductivity in beta-Cs3(HSO4)2(Hx(P,S)O4)," Solid State Ionics, vol. 97, no. 1-4, pp. 145-151, 1997.

C. R. I. Chisholm, and S. M. Haile, "Structure and thermal behavior of the new superprotonic conductor Cs2(HSO4) (H2PO4)," Acta Crystallographica Section B-Structural Science, vol. 55, pp. 937-946, 1999.

C. R. I. Chisholm, and S. M. Haile, "Superprotonic behavior of Cs2(HSO4)(H2PO4) - a new solid acid in the CsHSO4-CsH2PO4

system," Solid State Ionics, vol. 136, pp. 229-241, 2000.

O. S. Hernández-Daguer, H. Correa, and R. A. Vargas, "Phase behaviour and superionic phase transition in K3H(SeO4)2," Ionics, vol. 21, no. 8, pp. 2201-2209, 2015.

D.-K. Lim, J. Liu, S. A. Pandey, H. Paik, C. R. I. Chisholm, J. T. Hupp, and S. M. Haile, "Atomic layer deposition of Pt@Cs H2PO4 for the cathodes of solid acid fuel cells," Electrochimica Acta, vol. 288, pp. 12-19, 2018.

D.-K. Lim, A. B. Plymill, H. Paik, X. Qian, S. Zecevic, C. R. I. Chisholm, and S. M. Haile,"Solid Acid Electrochemical Cell for the Production of Hydrogen from Ammonia," Joule, vol. 4, no. 11, pp. 2338-2347, 2020.

L. A. Cowan, R. M. Morcos, N. Hatada, A. Navrotsky, and S. M. Haile, "High temperature properties of Rb3H(SO4)2 at ambient pressure: Absence of a polymorphic, superprotonic transition," Solid State Ionics, vol. 179, no. 9-10, pp. 305-313, 2008.

C. Panithipongwut, and S. M. Haile, "High-temperature phase behavior in the Rb3H(SO4)2–RbHSO4 pseudo-binary system and the new compound Rb5H3(SO4)4," Solid State Ionics, Article; Proceedings Paper vol. 213, pp. 53-57, 2012.

A. I. Baranov, "Crystals with disordered hydrogen-bond networks and superprotonic conductivity. Review," Crystallography Reports, vol. 48, no. 6, pp. 1012-1037, 2003.

M. W. Louie, M. Kislitsyn, K. Bhattacharya, and S. M. Haile, "Phase transformation and hysteresis behavior in Cs1-xRbx H2PO4," Solid State Ionics, vol. 181, no. 3-4, pp. 173-179, 2010.

A. Pawlowski, L. Szczesniak, M. Polomska, B. Hilczer, and L. Kirpichnikova, "Pretransitional effects at the superionic phase transition of Rb3H(SeO4)2 protonic conductor," Solid State Ionics, vol. 157, no. 1-4, pp. 203-208, 2003.

C. P. Kowalski, P. Chaijaroen, and F. Kaewniyom, "Thermal

behavior of solid acids in the Rb3H(SO4)2–RbHSO4 system under ambient atmosphere," Journal of Metals, Materials and Minerals, vol. 31, no. 1, pp. 57-63, 2021.

M. Sakashita, H. Fujihisa, K. I. Suzuki, S. Hayashi, and K. Honda, "Using X-ray diffraction to study thermal phase transitions in Cs5H3(SO4)4⋅xH2O," Solid State Ionics, vol. 178, no. 21-22, pp. 1262-1267, 2007.

S. Fortier, M. E. Fraser, and R. D. Heyding, "Structure of trirubidium hydrogenbis(sulfate), Rb3H(SO4)2," Acta Crystallographica Section C, vol. 41, no. 8, pp. 1139-1141, 1985.

K. Itoh, H. Ohno, and S. Kuragaki, "Disordered structure of ferroelectric rubidium hydrogen sulfate in the paraelectric phase," Journal of the Physical Society Japan, vol. 64, no. 2, pp. 479-484, 1995.




How to Cite

C. P. . KOWALSKI, “Retaining the high-temperature phases of Rb3H(SO4)2 and Rb5H3(SO4)4 at room temperature”, J Met Mater Miner, vol. 31, no. 4, pp. 116–122, Dec. 2021.



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