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Natalya Tarasova works on the creation of new proton conductors. Photo credit: Ilya Safarov. |
Scientists from the Ural Federal University and the Institute of High Temperature Electrochemistry of the Ural Branch of the Russian Academy of Sciences carried out the first demonstration of donor and acceptor doping of perovskite with a barium-lanthanum indite block-layer structure. The fundamental possibility of such a method to significantly improve the conducting properties of the material was shown. The work opens a new way to the creation of solid oxide fuel cell electrolytes. An article describing the research and its results was published in Ceramics International.
One of the goals of global materials science is to obtain the highest possible electrical conductivity of electrolytes for their further use in solid oxide fuel cells. For this purpose, doping is the replacement of part of the atoms in the starting materials by atoms of another chemical element (acceptor doping is replacement by atoms with a lower valence, donor doping is replacement by atoms with a higher valence).
"We used barium-lanthanum iodate as the initial structure and during our studies we substituted some indium atoms for titanium (donor doping) and some lanthanum atoms for calcium (acceptor doping) in it. When acceptor doping, oxygen defects - oxygen vacancies - appeared in the crystal lattice of the initial material. This can ensure the transfer of protons - positively charged hydrogen ions - along the crystal lattice. They get into the structure of layered perovskite from humidified air at 300-500°C. The more oxygen defects and, consequently, the greater the concentration of protons in the perovskite crystal lattice and their mobility, i.e. speed, the higher the values of the electrical conductivity of the material," explains Natalya Tarasova, Professor of the Department of Physical Chemistry and Leading Researcher of the Institute of Hydrogen Energy at UrFU.