At present, most of the scientific effort is aimed at producing energy in the most environmentally friendly and economical way, including using renewable energy sources. However, their use is associated with a number of problems (low efficiency, special requirements for natural conditions, high cost, etc.). Therefore, in recent decades, special attention has been paid to the development of chemical energy sources, including fuel cells. As well as lowering the operating temperature of the solid oxide fuel cell without lowering the efficiency. To perform the latter task, a scientifically valid selection of electrolyte materials with sufficient conductivity at a lower temperature and electrodes (cathode and anode) with acceptable performance characteristics is required.
A series of phases stable over wide ranges of temperature and partial oxygen pressure, exhibiting high mixed electronic-ionic conductivity, and promising as fuel cell electrodes can be formed in the Ln–M–T–O systems (Ln is a rare-earth element; М is Ca, Sr, or Ba; T is a 3d-element). Depending on the composition and external conditions in these oxides, a structural ordering of the atoms of the lanthanide and alkaline earth metal (Ba) in the A sublattice can occur, leading to the localization of oxygen vacancies in certain planes, and, as a consequence, the rapid transport of oxygen ions. High mobility of oxygen ions, along with large values of electronic conductivity, stability in oxidizing atmospheres, makes these materials promising for use in various electrochemical devices, for example, as SOFC electrodes, membranes for oxygen concentration, gas sensors, etc.
The studies proposed in this project will be aimed at revealing the fundamental laws linking the composition and structure, the physico-chemical properties of complex oxides of Y2-уBa3 + уFe5-xCoxO13 ± d, promising for use as materials in various devices. Data will be obtained on the phase formation processes in the synthesis of these compounds, on the thermodynamic stability, the crystal structure of the corresponding phases, and their physico-chemical properties.