Discovery and development of BaNdInO₄ —A brief review—

Abstract

This article provides the first critical review on the discovery and development of BaNdInO 4. Exploring a new structure family of ionic conductors is an important task to develop ceramic ionic conductors. Since some A 2 BO 4 compositions exhibit high oxide-ion conductivities, we investigated ABCO 4 compositions to explore new oxideion conductors with A/B/C cation-ordered structures. Here A, B and C are cations [ionic radii: r(A) ² r(B) ² r(C)]. In 2014, we discovered a new material BaNdInO 4 which belongs to a new structure family of perovskiterelated structures. This BaNdInO 4-type structure (monoclinic, P2 1 /c) consists of alternative stacking of the A rare earth oxide unit and perovskite unit with a ¹ b ¹ c ¹ tilt system. We also discovered new materials BaRInO 4 (R = Sm, Y, Ho, Er, Yb) having the BaNdInO 4-type structure, and report their lattice parameters and anisotropic chemical expansion. Electrical conductivity of BaNdInO 4 was higher than those of BaRInO 4 (R = Sm, Y, Er). Oxide-ion conduction was dominant for BaNdInO 4 in the P(O 2) region from 3.8 © 10 ¹22 to 5.5 © 10 ¹9 atm at 858°C. Oxide-ion conductivities of Ba 1.1 Nd 0.9 InO 3.95 , BaSr 0.1 Nd 0.9 InO 3.95 and BaCa 0.2 Nd 0.8 InO 3.9 were higher than that of BaNdInO 4. Structure analyses of Ba 1.1 Nd 0.9 InO 3.95 and BaSr 0.1 Nd 0.9 InO 3.95 indicated that the excess Ba and doped Sr cations were partially substituted for Nd cation and that there existed oxygen vacancies, leading to the increase of the carrier concentration and higher oxide-ion conductivity. Following the discovery of BaNdInO 4 , BaRScO 4 (R = Nd, Eu, Y, Yb) and SrYbInO 4 were reported as new ABCO 4 materials. BaYScO 4 and BaYbScO 4 have the BaNdInO 4-type structure. BaNdScO 4 and BaEuScO 4 crystallize into the space group Cmcm, which has a higher symmetry than P2 1 /c for BaNdInO 4. SrYbInO 4 is the first example of pure oxide-ion conductors with CaFe 2 O 4-type structure. Further investigations of ABCO 4 compositions and BaNdInO 4 related materials will lead to development of materials science and solid state ionics.

Rare earth elements based oxide ion conductors

“…Subsequently, the NdBaInO 4 -type-derived materials of BaLnInO 4 (Ln: Sm, Y, Ho, Er, or Yb) were discovered and investigated, including their lattice parameters and anisotropic chemical expansion. 185…”

Incorporation and Conduction of Protons in Ca, Sr, Ba-Doped BaLaInO4 with Ruddlesden-Popper Structure

“…The new compounds BaYInO 4 , BaSmInO 4 , BaHoInO 4 , BaErInO 4 , and BaYbInO 4 were also synthesized [16,17], but the total electrical conductivity of BaNdInO 4 was the highest among BaRInO 4 compounds. Therefore, the investigations were mainly focused on BaNdInO 4 .…”

“…The interstitial oxygen conduction was also discussed in the donor doped K 2 NiF 4 -type LaSrInO 4 oxides [19,20]. It should also be mentioned that Kotaro Fujii et al [17] emphasized that there is no direct evidence for the interstitial oxygen. In the BaNdInO 4 -type structure, there is no rock-salt block, but the A rare earth oxide unit could have an influence on the impurity phases.…”

Oxide-ion conduction in the Dion–Jacobson phase CsBi2Ti2NbO10−δ

“…xide-ion conductors have attracted much attention because of their extensive applications, including in solidoxide fuel cells, gas sensors, oxygen separation membranes, and catalysts [1][2][3][4][5][6][7][8][9] . Due to the interaction of oxide ions with the cation network, high oxide-ion conductivities have been achieved in a limited number of structure families; for example, the fluorite-type, perovskite-type, melilite-type, and apatite-type structures [10][11][12][13][14][15][16][17] . Since the limited structure families restrict further development in chemistry and solid-state ionics, the discovery of oxide-ion conductors with new crystal structures is of vital importance for the development of their applications.…”

“…Here, we have screened 69 Dion-Jacobson phases using available crystallographic data and the bond-valence method (see the details in Supplementary Methods, Supplementary Fig. 1 and Supplementary Table 1) 12,13,16,17,37,38,40,[50][51][52][53] . The chemical composition of CsBi 2 Ti 2 NbO 10 is selected because the bondvalence-based energy barrier for the oxide-ion migration, E b , is relatively low (E b = 0.5 eV) and CsBi 2 Ti 2 NbO 10 does not contain expensive rare-earth elements.…”