Correlation between Structural and Transport Properties of Ca-Doped La Nickelates and Their Electrochemical Performance
Elena Pikalova,
Vladislav Sadykov,
Ekaterina Sadovskaya,
Nikita Yeremeev,
Alexander Kolchugin,
Alexander Shmakov,
Zakhar Vinokurov,
Denis Mishchenko,
Elena Filonova,
Vladimir Belyaev
Affiliations
Elena Pikalova
Institute of High Temperature Electrochemistry UB RAS, 620066 Yekaterinburg, Russia
Vladislav Sadykov
Federal Research Center Boreskov Institute of Catalysis, 630090 Novosibirsk, Russia
Ekaterina Sadovskaya
Federal Research Center Boreskov Institute of Catalysis, 630090 Novosibirsk, Russia
Nikita Yeremeev
Federal Research Center Boreskov Institute of Catalysis, 630090 Novosibirsk, Russia
Alexander Kolchugin
Institute of High Temperature Electrochemistry UB RAS, 620066 Yekaterinburg, Russia
Alexander Shmakov
Federal Research Center Boreskov Institute of Catalysis, 630090 Novosibirsk, Russia
Zakhar Vinokurov
Federal Research Center Boreskov Institute of Catalysis, 630090 Novosibirsk, Russia
Denis Mishchenko
Federal Research Center Boreskov Institute of Catalysis, 630090 Novosibirsk, Russia
Elena Filonova
Department of Physical and Inorganic Chemistry, Institute of Natural Sciences and Mathematics, Ural Federal University Named after the First President of Russia B.N. Yeltsin, 620002 Ekaterinburg, Russia
Vladimir Belyaev
Federal Research Center Boreskov Institute of Catalysis, 630090 Novosibirsk, Russia
This work presents the results from a study of the structure and transport properties of Ca-doped La2NiO4+δ. La2−xCaxNiO4+δ (x = 0–0.4) materials that were synthesized via combustion of organic-nitrate precursors and characterized by X-ray diffraction (XRD), in situ XRD using synchrotron radiation, thermogravimetric analysis (TGA) and isotope exchange of oxygen with C18O2. The structure was defined as orthorhombic (Fmmm) for x = 0 and tetragonal (I4/mmm) for x = 0.1–0.4. Changes that occurred in the unit cell parameters and volume as the temperature changed during heating were shown to be caused by the excess oxygen loss. Typical for Ruddlesden–Popper phases, oxygen mobility and surface reactivity decreased as the Ca content was increased due to a reduction in the over-stoichiometric oxygen content with the exception of x = 0.1. This composition demonstrated its superior oxygen transport properties compared to La2NiO4+δ due to the enhanced oxygen mobility caused by structural features. Electrochemical data obtained showed relatively low polarization resistance for the electrodes with a low Ca content, which correlates well with oxygen transport properties.
