(AGENPARL) - Roma, 6 Giugno 2023 - (AGENPARL) – mar 06 giugno 2023 PRESS RELEASE
Source: Tokyo Institute of Technology
For immediate release: June 6, 2023
Headline: Ba2LuAlO5: A New Proton Conductor for Next-Generation Fuel Cells
(Tokyo, June 6)
*The discovery of Ba2LuAlO5 as a promising proton conductor paints a
brightfuture for protonic ceramic fuel cells, report scientists from Tokyo
Tech. Experiments showthat this novel material has a remarkably high proton
conductivity even without anyadditional chemical modifications, and
molecular dynamics simulations reveal theunderlying reasons. These new
insights may pave the way to safer and more efficient energy technologies.*
When talking about sustainability, the ways in which a society generates
energy are some of the most important factors of consideration. Eager to
eventually replace traditional energy sources such as coal and oil,
scientists across the world are trying to develop environmentally friendly
technologies that produce energy safely and more efficiently. Among them,
fuel cells have been steadily gaining traction since the 1960s as a
promising approach to producing electricity directly from electrochemical
reactions.
However, typical fuel cells based on solid oxides have a notable drawback
in that they operate at high temperatures, usually over 700 °C. That is why
many scientists have focused on protonic ceramic fuel cells (PCFCs)
instead. These cells use special ceramics that conduct protons (H+) instead
of oxide anions (O2?). Thanks to a much lower operating temperature in the
range of 300 to 600 °C, PCFCs can ensure a stable energy supply at a lower
cost, compared to most other fuel cells. Unfortunately, only a few
proton-conducting materials with reasonable performance are currently
known, which is slowing down progress in this field.
To address this challenge, a team of researchers, including Professor
Masatomo Yashima from Tokyo Institute of Technology (Tokyo Tech) in Japan,
has been on the lookout for good proton conductor candidates for PCFCs. In
their latest study, published in *Communications Materials*
<https://doi.org/10.1038/s43246-023-00364-5>, the team reported the
remarkable properties of Ba2LuAlO5, a new hexagonal perovskite-related
oxide that has provided interesting insights into proton conduction.
Prof. Yashima and colleagues discovered Ba2LuAlO5 while focusing on finding
compounds with a lot of intrinsic oxygen vacancies. This was motivated by
the results of previous studies highlighting the importance of these
vacancies in proton conduction. Experiments on Ba2LuAlO5 samples revealed
that this material has a high proton conductivity in its bulk at low
temperatures—its conductivity was 10?2 S cm?1 at 487 °C and 1.5×10?3 S cm?1
at 232 °C—even without additional chemical refinements such as doping.
Afterwards, the team sought to find out the underlying reasons for this
property. Through molecular dynamics simulations and neutron diffraction
measurements, they learned two important characteristics of Ba2LuAlO5. The
first is that this oxide absorbs a lot of water (H2O), compared to other
occurs within two opposing layers of AlO4 tetrahedra, is made possible by a
high number of intrinsic oxygen vacancies in the hexagonal close-packed h’
BaO layers. In turn, the oxide’s higher water content increases its proton
conductivity through various mechanisms, such as higher proton
concentration and enhanced proton hopping.
The second important characteristic is related to how protons move through
Ba2LuAlO5. Simulations revealed that protons diffuse mainly along the
interfaces of LuO6 layers, which form cubic close-packed c BaO3 layers,
rather than through the AlO4 layers. This information could be critical in
the search for other proton conducting materials, as Prof. Yashima
explains: “Our work provides new design guidelines that open up unexplored
avenues for the development of higher-performance proton conductors in the
future.”
The researchers expect to find other proton-conducting materials based on Ba
2LuAlO5 in upcoming studies. “By modifying the chemical composition of Ba2
LuAlO5, further improvements in proton conductivity can be expected,”
comments Prof. Yashima, “For example, the perovskite-related oxide Ba2InAlO5
may also exhibit high conductivity since its structure is quite similar to
that of Ba2LuAlO5.”
Overall, the future of PCFCs seems bright and, by extension, so does the
future of sustainable energy generation technologies.
*Reference*
Authors:
Riho Morikawa,1 Taito Murakami,1 Kotaro Fujii,1 Maxim Avdeev,1, 2,3 Yoichi
Ikeda,4 Yusuke Nambu,4,5,6 and Masatomo Yashima1,*
Title:
High Proton Conduction in Ba2LuAlO5 with Highly Oxygen Deficient Layers
Journal:
*Communications Materials*
DOI:
10.1038/s43246-023-00364-5 <https://doi.org/10.1038/s43246-023-00364-5>
Affiliations:
1Department of Chemistry, School of Science, Tokyo Institute of Technology
2Australian Centre for Neutron Scattering, Australian Nuclear Science and
Technology Organisation (ANSTO)
3School of Chemistry, The University of Sydney
4Institute for Materials Research, Tohoku University
5 Organization for Advanced Studies, Tohoku University
6 FOREST, Japan Science and Technology Agency
*Infographic*
https://tokyotech.box.com/s/lal5e42mij5g08vr5t22h5fh99awslbt
*Contact*
Emiko Kawaguchi
Public Relations Division
Tokyo Institute of Technology