Progress in hydrogen energy and promising directions for its modern development are closely related to the development of fuel cells, including solid oxide fuel cells, and solid state membranes for hydrogen, oxygen and synthesis gas production. A necessary condition for fabrication the economically competitive devices in this area is the use of cheap electrode materials combining high electrochemical activity and long-term stability. Ln2NiO4+δ oxides with the Ruddlesden-Popper layered structure with a high mixed ion-electron conductivity and moderate values of the coefficients of thermal expansion are promising materials for the development of oxygen-conducting membranes and cathodes of intermediate-temperature solid oxide fuel cells. The paper studies the structure, electrical conductivity, oxygen mobility and electrochemical properties of Ln2-xCaxNiO4+δ (Ln = La, Pr, Nd; x = 0; 0.3) in order to determine the factors that have the most significant effect on the electrochemical activity of electrodes and their stability. We have found that doping with calcium leads to stabilization of the structure and an increase in the electrical conductivity of materials. However, addition of calcium decreases the electrochemical activity of the electrodes in varying degrees depending on the nature of the lanthanide. There is no direct interrelation of such a decrease of activity with either the electrical properties or the interstitial oxygen content. We have revealed correlation of the polarization resistance of electrodes between characteristics of oxygen transfer in the electrode material (self-diffusion coefficient, surface exchange constant). Using the C18O2 SSITKA method, the total oxygen mobility in the doped materials is shown to fall due to a decrease in the content of highly mobile interstitial oxygen and hampering of the cooperative oxygen transport mechanism. In the case of La1.7Ca0.3NiO4+δ, this leads to the appearance of a slow diffusion channel and a substantial decrease in the total diffusion coefficient value which leads to a sharp increase in the polarization resistance of the electrodes. This phenomenon is not observed in materials with praseodymium and neodymium. The electrodes based on Pr1.7Ca0.3NiO4+δ and Nd1.7Ca0.3NiO4+δ, developed in this work, have an acceptable level of the electrochemical activity along with a high electrical conductivity and increased stability in comparison with undoped compositions and can be recommended for use as cathodes for intermediate temperature fuel cells.
Translated title of the contributionStructure, Transport Properties and Electrochemical Behavior of the Layered Lanthanide Nickelates Doped with Calcium
Original languageRussian
Pages (from-to)70-93
Number of pages24
JournalМеждународный научный журнал "Альтернативная энергетика и экология"
Issue number1-3 (249-251)
DOIs
Publication statusPublished - 2018

    GRNTI

  • 31.15.00

    Level of Research Output

  • VAK List

ID: 6911338