In-situ diffraction study of Ba2In2O5

Enhancement of the conductivity of Ba2In2O5 through phosphate doping

“…For the electrolyte in such devices, a material displaying either high oxide ion conductivity or proton conductivity at elevated temperatures is required, with the main focus of research in this field being materials with the fluorite or perovskite structures [1][2][3] . One of the most well known perovskite-related oxide ion conductors is Ba 2 In 2 O 5 , whose oxide ion conductivity is closely linked to its crystal structure 4,5 . At room temperature, it adopts an orthorhombic brownmilleritetype structure (figure 1) containing ordered oxide ion vacancies, leading to alternating layers of InO 6 octahedra and InO 4 tetrahedra.…”

“…As a result of this ordering of the oxide ion vacancies, the oxide ion conductivity is comparatively low. At a temperature of ≈ 930 °C, there is a phase change from orthorhombic to tetragonal resulting in disordering of these oxygen vacancies, and a corresponding discontinuous jump in oxide ion conductivity by more than an order of magnitude 4,5 . At higher temperature still, above 1040 °C, the cell becomes cubic, as the oxide ion vacancies become completely disordered 5 .…”

A neutron diffraction study of the oxygen diffusion in molybdenum doped Ba2In2O5

“…The structure of the tetragonal polymorph of Ba 2 In 2 O 5 was tentatively described by Speakman et al in the following unit cell a T =b T =a B = 2 a P and c T =b B =4a P [9]. They obtained the best agreement factors in the I4cm space group.…”

“…For temperatures higher than 1040°C, Ba 2 In 2 O 5 transforms to an oxygen deficient perovskite with cubic symmetry which can be described in the Pm 3 m space group. These two high temperature (tetragonal and cubic) forms are pure oxide ion conductors [3][4][5][6][7][8][9] and were tentatively stabilised at room temperature by partial substitution for barium and/or indium. Our group investigated the partial substitution for indium with high valence state metals.…”

Structure of Ba2In2−xVxO5+x phases: Complementarity of diffraction, Raman and absorption techniques

“…Because of its oxide ion conduction properties, Ba 2 In 2 O 5 has a potential of application as electrolyte for solid oxide fuel cells, oxygen generating systems or membrane for dense catalytic reactors [1][2][3][4]. At room temperature, it adopts the Brownmillerite structure.…”