Controlling Oxygen Mobility in Ruddlesden–Popper Oxides

Abstract

Discovering new energy materials is a key step toward satisfying the needs for next-generation energy conversion and storage devices. Among the various types of oxides, Ruddlesden–Popper (RP) oxides (A2BO4) are promising candidates for electrochemical energy devices, such as solid oxide fuel cells, owing to their attractive physicochemical properties, including the anisotropic nature of oxygen migration and controllable stoichiometry from oxygen excess to oxygen deficiency. Thus, understanding and controlling the kinetics of oxygen transport are essential for designing optimized materials to use in electrochemical energy devices. In this review, we first discuss the basic mechanisms of oxygen migration in RP oxides depending on oxygen nonstoichiometry. We then focus on the effect of changes in the defect concentration, crystallographic orientation, and strain on the oxygen migration in RP oxides. We also briefly review their thermal and chemical stability. Finally, we conclude with a perspective on potential research directions for future investigation to facilitate controlling oxygen ion migration in RP oxides.

Defect Engineering for Photocatalysis: From Ternary to Perovskite Oxynitrides

“…For ABO 3 oxide perovskites the transition from a 3D perovskite to a 3D layered RP phase AO(ABO 3 ) n can yield improvements in ion conductivity and dielectric properties (along with increased anisotropy of these properties), as well as higher photocatalytic activity in the layered phases . Figure depicts the variation in the RP phases as a function of n, where n indicates how many ABO 3 layers stack between rock salt AO layers; at the limit of n=∞ a native perovskite phase occurs.…”

Gas Humidification Impact on the Properties and Performance of Perovskite‐Type Functional Materials in Proton‐Conducting Solid Oxide Cells

“…The parameters of the first group lie in the materials science aspect and can be managed by the selection and optimization of electrode compositions; the parameters of the second group can be controlled through the optimization of technological methods. Analysis on the relationship between the electrochemical activity, kinetic and microstructural parameters has been thoroughly carried out . However, the influence of air humidification on the oxygen electrodes' performance was not clear, particularly for the proton‐conducting SOCs.…”

Environmental TEM Investigation of Electrochemical Stability of Perovskite and Ruddlesden–Popper Type Manganite Oxygen Evolution Catalysts

“…[21] Moreover, RP systems show a much higher oxygen mobility parallel to the layers compared to perovskites and its change of lattice parameter as a function of oxygen content is one order of magnitude smaller, leading to reduced vacancy induced strain. [43,44] Differences in both properties are presumably important for explaining the observed enhanced stability of the RP phase under reactive conditions compared to the P phase. The ETEM study is extended to non-OER conditions in O 2 and/or He.…”