Dynamics in Bi(iii)-containing apatite-type oxide ion conductors: a combined computational and experimental study

Abstract

Introduction of Bi(iii) into apatite-type germanate solid electrolytes can facilitate oxide ion diffusion.

Chemical Bonding Effect on the Incorporation and Conduction of Interstitial Oxide Ions in Gallate Melilites

“…Finally, it is interesting to note here that the detrimental effect of the lone pair Pb 2+ on the interstitial oxide ion conduction in melilite differs from the more recently discovery of improved oxide ion mobility from the substitution of lone pair‐containing Bi 3+ for La 3+ in the interstitial oxide ion conducting apatite La 10 Ge 6 O 27 . In this apatite case, the Bi has no direct interaction with the interstitial defect but the asymmetric bonding environment around the lone pair‐containing Bi 3+ reduces the distance between the channel oxygen and the GeO 4 network, promoting the oxide ion exchange between the channel and the network as well as the migration along the channel itself.…”

“…DFT Calculations : The calculations were performed using DFT with the projected augmented wave (PAW) method using the Vienna ab initio simulation package (VASP), which is effective for describing the crystal and electronic structures of condensed matter. For the exchange‐correlation functional, a Perdew–Burke–Ernzerhof (PBE) generalized gradient approximation (GGA) was employed. For valence electrons, the outermost s, p, d, and f states of the La atoms, s, p, and d states of the Ga and Pb atoms, and s and p states of the O and Sr atoms were included.…”

Exploring the nature of the fergusonite–scheelite phase transition and ionic conductivity enhancement by Mo6+doping in LaNbO4

“…Although BVS is an empirical quantity and BVEL maps must be interpreted with caution, such maps have been shown to reproduce low-energy ionic conduction pathways determined experimentally or computationally in several ionic-conductive materials. [59][60][61][62] BVEL mapping has also been used successfully to screen known database structures for oxide-ionic conductivity which was subsequently conrmed experimentally in several materials for the rst time. 63,64 A BVEL map that we calculated for a geometry-optimised undoped LaNbO 4 supercell produced low-energy pathways that show good qualitative agreement with those derived from the nudged elastic band calculations of Toyoura et al 27 (ESI Fig.…”

Single-phase white-emitting phosphors based on apatite-type gadolinium silicate, Gd9.33(SiO4)6O2 doped with Dy3+, Eu3+ and Tb3+

“…For example, the emission of the phosphor MgY 4 Si 3 O 13 : 0.02%Ce 3+ , 0.2%Tb 3+ , xEu 3+ (x = 0.16, 0.22, 0.28, 0.34 and 0.40) can be tuned to white, under near-UV excitation at 355 nm. 30 The material shows energy transfer processes from Ce 3+ to Tb 3+ and from Tb 3+ to Eu 3+ . The average Tb 3+ luminescence lifetime value shows a decrease as the Eu 3+ doping increases, indicative of energy transfer from the 5 D 4 state of Tb 3+ to Eu 3+ .…”

“…They mostly crystallise in hexagonal structure in space group P6 3 /m, though some adopt monoclinic or triclinic structures. [29][30][31][32][33] The apatite structure can be described as a zeolite-like framework in which columns of face-sharing AO 6 trigonal prisms (shown in Fig. 2 in pink polyhedra) share corners with XO 4 tetrahedra (shown in Fig.…”