Engineering mass transport properties in oxide ionic and mixed ionic-electronic thin film ceramic conductors for energy applications

Abstract

New emerging disciplines such as Nanoionics and Iontronics are dealing with the exploitation of mesoscopic size effects in materials, which become visible (if not predominant) when downsizing the system to the nanoscale. Driven by the worldwide standardisation of thin film deposition techniques, the access to radically different properties than those found in the bulk macroscopic systems can be accomplished. This opens up promising approaches for the development of advanced micro-devices, by taking advantage of the nanostructural deviations found in nanometre-sized, interface-dominated materials compared to the "ideal" relaxed structure of the bulk. A completely new set of functionalities can be explored, with implications in many different fields such as energy conversion and storage, or information technologies. This manuscript reviews the strategies, employed and foreseen, for engineering mass transport properties in thin film ceramics, with the focus in oxide ionic and mixed ionic-electronic conductors and their application in micro power sources.

Developments in X-ray tomography characterization for electrochemical devices

“…However, issues with, for instance, the cathode current collection may also provide valuable insight into performance loss if evaluated in 4D. Furthermore, many chemistries are emerging as next-generation electrode materials such as mixed-ionic-electronic-conductors (MIECs) [182], which may also benefit from such studies. Finally, there are many possibilities for employing XRD-CT to investigate SOFC materials; although investigations using point-and powder-XRD into SOFCs, particularly with focus on the anode [49,50], have proven very valuable, extending such studies to become spatially resolved would further elucidate the origins and developments of cell constituents.…”

Transport Properties of Film and Bulk Sr0.98Zr0.95Y0.05O3−δ Membranes

“…One can assume that the difference is caused by a larger contribution of the grain boundary resistance of the film because of the smaller grain size compared to the bulk sample. It is known that in oxygen-ion conducting solid electrolytes, ion transport across the grain boundary regions is hindered because of oxygen vacancy accumulation and formation of a positively charged core [4,[36][37][38][39]. The activation energy of the effective conductivity of the film (98 eV) is somewhat higher than that of the bulk membrane (85 eV) that also indicates the larger contribution of grain boundaries typically possessing higher activation barriers in solid oxide electrolytes [40].…”

“…A further enhancement of SOFC performance can be achieved through a decrease in electrolyte thickness. Nowadays, the application of thin-film membranes for the development of portable powering microdevices is considered a significant part of an upcoming nanoionics revolution [4,5]. The high performance of SOFCs with a thin-film electrolyte was demonstrated in [6][7][8][9][10][11][12][13][14].…”

“…The high performance of SOFCs with a thin-film electrolyte was demonstrated in [6][7][8][9][10][11][12][13][14]. However, thin-film SOFC efficiency was reported to be sensitive to the diffusional interaction between the electrolyte and the electrodes [4,[15][16][17][18][19]. Thin films usually exhibit a nanograined structure, which enhances the effect of material interaction as diffusion along the grain boundaries is much faster than in the grain bulk [16,19,20].…”

Progress and Perspectives of Atomically Engineered Perovskite Oxide Interfaces for Electronics and Electrocatalysts

“…Atomically engineered oxide interfaces for electrocatalystsAt relatively high temperatures, most perovskite oxides also show mixed electronic and ionic conductivity, important for oxygen redox reactions 118,119. The conventional way to tune the intrinsic activity of perovskite oxides is by chemical doping, which often introduces unintentional impurities.…”