Scientists at the Ural Federal University (UrFU) and the URAS Institute of High Temperature Electrochemistry have synthesized a proton conductor, a solid electrolyte in which positively charged hydrogen (proton) particles are current carriers. It has a high level of electrical conductivity and could become the basis for a solid oxide fuel cell (SOFC). Such cells are an environmentally friendly alternative to hydrocarbon energy sources. The results of the study are published in the International Journal of Hydrogen Energy.
Solid oxide fuel cells are instruments that convert fuel energy into electrical energy through a chemical reaction. SOFC are used in hydrogen power, they can replace fossil fuel sources and reduce their impact on climate change and air pollution. Such cells can be used in car engines or the space industry to reduce hydrocarbon emissions into the environment. Fuel cells based on the new material developed by scientists are potentially cost-effective to produce and can exhibit higher electrical conductivity than other solid-state conductors for SOFC.
“The transition to clean hydrogen energy is one of the possible ways to solve the problem of fossil fuel pollution. Proton-ceramic fuel cells are a promising alternative to hydrocarbon engines, because they combine high efficiency, flexibility in various operating conditions, and excellent performance. We obtained a new energy-efficient material in which the proton concentration is doubled and the electrical conductivity becomes two times higher. It is important to note that the material shows such results at a temperature that is twice as low as the currently most studied solid-state oxygen-ion conductors. Lowering the temperature increases the economic efficiency of the final electrochemical device,” explains co-author, associate professor at the Department of Physical Chemistry at UrFU Natalia Tarasova.
Scientists obtained new material by the isovalent doping method. It was first used to improve the properties of the substance under study. It turned out that this method helped to achieve high indicators. Isovalent doping means substitution of atoms of the initial structure with atoms of another chemical element of the same valence. In this case, they used barium-lanthanum indate (a compound of barium, lanthanum, indium, and oxygen), where scientists substituted half of the indium atoms for yttrium.
“Solid-state proton conductors, which can be used in SOFC, introduce protons into themselves from moist air, that is, from the water contained in it. Yttrium has a larger radius than indium, and when introduced, it "pulls apart" the crystal lattice of the source material. This allows the altered lattice to "accumulate" twice as many protons from the humidified atmosphere,” adds Tarasova.
Materials based on barium-lanthanum indate with a block-layer structure are a unique development of UrFU scientists. Before their discovery, materials with a perovskite (calcium titanate) structure were mainly studied as proton conductors.
- This press release was originally published on the Ural Federal University website