A multicomponent equimolar proton-conducting quadruple hexagonal perovskite-related oxide system

Abstract

Since the high configurational entropy-driven structural stability of the multicomponent oxide system proposed by Rost et al. in 2015, many experiments and simulations have been done to develop new multicomponent...

Anisotropic Proton Migration in Hexagonal Perovskite-Related Ba5Er2Al2ZrO13 Oxide

“…This result undoubtedly shows that the preferentially oriented grains in the {0001} plane have a greater effect on the proton conduction than the Ba nonstoichiometry. As reported in previous work, 42 the sluggishness of the protonation kinetics of BEAZ highlights the need for extended periods of time to stabilize the proton conductivity and emphasizes the importance of carefully considering hydration conditions and sample thickness when studying proton conduction in the BEAZ system (see Figure S15 for hydration time for BEAZ depending on their thickness and sintering temperature). Therefore, in this study, the hydration reaction was carried out for a sufficient period of time, at least for 24 h. A more detailed analysis of the kinetics of proton incorporation will be performed in the future.…”

High Proton Conduction in the Octahedral Layers of Fully Hydrated Hexagonal Perovskite-Related Oxides

“…Later, Youn et al 33 ) have the same crystal structure as Ba 5 Er 2 Al 2 ZrO 13 (10H polytype, hexagonal crystal system, space group P6 3 /mmc) and also exhibit significant proton conductivity. 26,28,30,32,33 In general, a high proton concentration y is required for high proton conductivity. Here, the y values of hydrated perovskitetype BaBO 3−δ and hexagonal perovskite-related oxide Ba Ba 5 A 2 Al 2 ZrO 13 materials are not high due to partial hydration.…”

“…Later, Youn et al also showed the anisotropic proton migration in Ba 5 Er 2 Al 2 ZrO 13 experimentally and by density functional theory (DFT) calculations. Ba 5 A 2 Al 2 ZrO 13 -based oxides ( A = Dy, Tm, Yb, Lu, In, Y 1/4 Ho 1/4 Er 1/4 Yb 1/4 , Y 1/5 Dy 1/5 Ho 1/5 Er 1/5 Yb 1/5 , and Y 0.5 In 1.5 ) have the same crystal structure as Ba 5 Er 2 Al 2 ZrO 13 (10H polytype, hexagonal crystal system, space group P 6 3 / mmc ) and also exhibit significant proton conductivity. ,,,, …”

“…Many hexagonal perovskite-related oxides also contain cubic close-packed (c) and/or anion-deficient cubic close-packed (c′) layers. Recently, the hexagonal perovskite-related oxides have been reported to exhibit significant proton conduction without chemical doping due to the presence of intrinsic oxygen vacancies. ,,− Here, the intrinsic oxygen vacancies are the oxygen vacancies in a parent material. However, the proton conduction of hexagonal perovskite-related oxides has not been extensively studied compared to that in AB O 3−δ perovskite oxides. − Murakami et al reported Ba 5 Er 2 Al 2 ZrO 13 as a new class of proton conductors with high proton conductivity comparable to those of representative proton conductors (e.g., 10 –3 S cm –1 at 300 °C).…”