Proton jump diffusion dynamics in hydrated barium zirconates studied by high-resolution neutron backscattering spectroscopy

Abstract

High-resolution neutron backscattering spectroscopy reveals the atomic-scale motions of protons in hydrated barium zirconates.

Revisiting the Crystal Structure of BaCe0.4Zr0.4Y0.2O3−δ Proton Conducting Perovskite and Its Correlation with Transport Properties

“…However, between 200 and 600°C reasonable fits were obtained and the resulting parameters are shown in Table 1, together with the proton diffusion coefficients derived from the mean residence times. The diffusion coefficients obtained here are in good agreement with those previously determined also using QENS in doped barium zirconates (e.g., for BaZr 0.8 In 0.2 O 2.90 , D H ∼ 2.8 × 10 −7 cm 2 /s at 277°C, 55 and for BaZr 0.85 Y 0.15 O 2.925 , D H ∼ 2.5 × 10 −6 cm 2 /s at 400°C). 91 Fitting the data shown in Table 1 to an Arrhenius law, we obtain an activation energy of 245(30) meV.…”

“…Such a model has already been used by Noferini et al to analyze the QENS dynamics in another series of proton conducting perovskites. 55 At each temperature, 12 spectra were obtained and fitted using 3 main Q-independent parameters ( f 0 , l, and τ; see below) plus a set of auxiliary Q-dependent parameters to account for the arbitrary intensity scale and a flat background (see eq 3). As there is a strong correlation between f 0 and τ, on a second step the value of f 0 was fixed, l was also fixed to the average jump length obtained from the first set of fits at all temperatures considered 3.4(1) Å, and only the mean residence time was refined.…”

Structure–property correlation in oxide-ion and proton conductors for clean energy applications: recent experimental and computational advancements

“…[131][132][133][134][135] However, a recent QENS study by Noferini et al of BaZr 1Àx M x O 3Àx/2 with M ¼ Sc and Y for x ¼ 0.1 and M ¼ In for x ¼ 0.1, 0.2, and 0.25 using the high-resolution neutron backscattering technique does not point toward such a trapping behaviour. 136 Furthermore, a recent rst-principles calculations study on the archetypical proton conductor BaZr 0.8 Y 0.2 O 2.9 , as well as a combined inelastic neutron scattering (INS) and rst-principles calculations study of BaZr 0.5 In 0.5 O 2.75 showed that the dopants preferentially migrate along percolation paths of dopant ions throughout the perovskite lattice (Fig. 14c).…”

Local structure and vibrational dynamics in indium-doped barium zirconate

“…At sufficiently high temperatures, typically above 300 K, the protons can diffuse throughout the lattice through a two-stage mechanism that involves the transferring (hopping) of a proton from one oxygen to another, neighboring, one and a reorientational motion of the -OH group between such a transfer. [6][7][8][9][10][11][12][13] However, fundamental questions encompassing the defect chemistry of these materials remain, especially in regard to the local coordination environment and dynamics of protons and in general the role of dopant atoms for the proton transport properties.…”