Influence of texture and grain misorientation on the ionic conduction in multilayered solid electrolytes – interface strain effects in competition with blocking grain boundaries

Abstract

Interface strain and its influence on the ionic transport along hetero-interfaces has gained a lot of attention over the last decade and is controversially discussed. We investigate the relaxation of mismatch induced interfacial strain as a function of the degree of orientation/texture of the columnar crystallites and assess the impact on the oxygen ion conductivity in Er2O3/YSZ multilayer systems. Results from X-ray diffraction clearly show, that the width of the strained hetero-interface region increases with an increasing degree of orientation of the crystallites. The combined impact of film texture and strain at the hetero-interfaces of the film on the ionic conductivity however is not easily deduced from these measurements. The samples with the highest degree of orientation, i.e. with only one azimuthal variant, show strong anisotropic electrical properties. In samples with a lower degree of orientation, i.e. samples with a fiber texture, anisotropic properties cannot be detected, possibly due to a geometrical averaging of the electrical properties. The expected strain induced monotonic increase of the ionic conductivity with decreasing layer thickness and thus increasing interfacial influence could only be detected for samples with a fiber texture and a considerable degree of crystallite misorientation. This leads to the important conclusion that the texture and therefore the nature of the grain boundaries and their network influence the ionic conductivity of the multilayer thin films in the same order of magnitude as the misfit induced interface strain. Thus, the potential design of strain-controlled ionic conductors requires additionally the control of the microstructure in terms of grain orientation.

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

“…[105,106] Particularly relevant in this context is the case in which coherent interfaces are obtained in columnar multilayered structures: Here the lattice mismatch between the constituting phases is able to generate a new strain field at each interface irrespective of the total film thickness. [107,108] Several computational studies have been dedicated to the prediction of the effects of strain on ionic conductivity. Generally, a decrease of the migration enthalpy is expected as a consequence of a moderate tensile strain state, as pointed out by Yildiz et al [109] and De Souza et al [110] which predicted an enhancement of diffusivity of ≈ 10 3 times for 4 % strained YSZ and CeO2, respectively.…”

Highly textured and crystalline materials for rechargeable Li‐ion batteries

“…Consequently, the specific crystallographic arrangement of each ASSB component becomes increasingly crucial for efficient vacancy hopping of lithium ions. In recent years, interfacial design and crystal engineering that control lattice orientation have attracted attention as a key strategy for improving the performance of ASSBs 19–26 . Building the textured, epitaxial, and single crystalline systems is able to refine and disclose the interfacial behaviors of electrochemical mechanisms as well as to improve the durability and energy density of solid‐state batteries 27,28 .…”

“…In recent years, interfacial design and crystal engineering that control lattice orientation have attracted attention as a key strategy for improving the performance of ASSBs. [19][20][21][22][23][24][25][26] Building the textured, epitaxial, and single crystalline systems is able to refine and disclose the interfacial behaviors of electrochemical mechanisms as well as to improve the durability and energy density of solid-state batteries. 27,28 Furthermore, significant adverse events at interface, one of the major obstacles to ASSBs, can be successfully suppressed by optimizing the orientation order of electrodes and SEs.…”

Predicting Ionic Conductivity in Thin Films of Garnet Electrolytes Using Machine Learning

“…One of them is the strain influence. In recent decades, strain engineering was explored as an effective way to modulate material properties [16][17][18][19]. Thus, strain engineering was successfully applied for tuning the band structure [20,21], in valleytronics [22], for tuning ferroic properties [17,23,24], phase stabilization and transitions [25][26][27][28][29], Li ion [30][31][32][33] and oxygen ion [18,[34][35][36][37] conductivity control.…”