Improvement of oxygen-ionic and protonic conductivity of BaLaInO 4 through Ti doping
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ORIGINAL PAPER
Improvement of oxygen-ionic and protonic conductivity of BaLaInO4 through Ti doping N. Tarasova 1 & A. Galisheva 1 & I. Animitsa 1,2 Received: 23 April 2020 / Revised: 27 May 2020 / Accepted: 12 June 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract The solid solution BaLaIn1–хTiхO4+0.5х (0 ≤ x ≤ 0.15) with the Ruddlesden-Popper structure was obtained. It was proved that significant proton concentration is achieved by up to 1.25 mol H2O. The degree of hydration increased with increasing the dopant concentration and was determined by the size of the salt block. The Ti doping of BaLaInO4 led to the increase in the ionic (O2−, H+) conductivities up to ~ 1.5 orders of magnitude. The sample BaLaIn0.9Ti0.1O4.05 (x = 0.10) exhibited nearly pure oxygen-ionic (pH2O = 3.5·10−5 atm) and protonic (pH2O = 2·10−2 atm) transport at T < 400 °C and T < 450 °C, correspondingly. Keywords BaLaInO4 . Ruddlesden-Popper structure . Water uptake . Ti doping . Oxygen-ion conductivity . Protonic conductivity
Introduction Compounds with perovskite or perovskite-related structure are widely investigated due to their various physicochemical properties. These compounds can be used as magnetic [1, 2], catalytic [3, 4], electrode [5–7], and electrolyte [8, 9] materials. Perovskite structure ABO 3 is formed by a threedimensional network of corner-sharing octahedra [BO6] in the space between which atoms A are located in the cuboctahedron positions [AO12]. Among ion-conducting perovskites, the large number of studies are devoted to the investigations of perovskites in which alkaline earth elements with an oxidation state of + 2 (Ca2+, Sr2+, Ba2+) are in the Asublattice and atoms with an oxidation state + 4 are located in the B-sublattice (Ce4+, Ti4+, Zr4+). These materials are promising candidates for intermediate-temperature solid oxide fuel cells (SOFCs) [10–14]. The developments in this field are of current interest because of the possibility of the creation of long-term working SOFCs, based on components with high * N. Tarasova [email protected] * I. Animitsa [email protected] 1
Institute of Natural Sciences and Mathematics, Ural Federal University, Yekaterinburg, Russia
2
The Institute of High Temperature Electrochemistry of the Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Russia
and stable conductivity values; the use of such devices will allow to resolve such very actual problems as the decrease of air pollution due to high consumption of fossil fuels [15] and the exhaustion of the major fossil energy sources on earth [16]. There are several ways of enhancement of ionic conductivity in perovskites. Although the doping method is most often used, that is, partial replacement of A or B cations with ions with different oxidation states, but the development of a new classes of materials can be a powerful method with regard to overall convenience and efficiency. For example, such classes of materials, as (i) the double [17, 18] or (ii) layered [19, 20] perovskites, can be
