2024 IRG-1: Observation of Grain Boundary Electrostatic Characteristics in Perovskite Solid-State Electrolytes by Four-Dimensional Scanning Transmission Electron Microscopy
Grain boundaries (GB), which can significantly hinder Li-ion transport, are the bottleneck of improving solid electrolytes’ ionic conductivity. The atomic structure and electrostatic characteristics of GBs thus become pivotal areas of study in materials science.
In this work, we use computations to study the element segregations at the GB structures of (Li0.375Sr0.4375)(Ta0.375Nb0.375Zr0.125Hf0.125)O3 (LSTNZH). The anti-site energies are associated with swapping positions of different elements, for each element between the bulk and the GB regions. Notably, the anti-site energy associated with exchanging Ta at the GB and Nb in the bulk is found to be less than zero. This indicates a thermodynamic preference for Nb to migrate towards the GB region, while Ta is more likely to shift towards the bulk, in line with experimental observations. Further simulations are conducted to elucidate the resultant charge accumulation.
This work reveals the formation of nanoscale electrostatic in the LSTNZH, which offers new insights into the mechanisms behind lowering GB resistivity through elemental segregation.
Prof. Shyue Ping Ong at UCSD
Chaojie Du1, Tom Lee1, Zishen Wang1, Yifeng Huang, Shu-Ting Ko, Ji Qi, Toshihiro Aoki, Zhaokun Wang, Jian Luo*, Shyue Ping Ong*, and Xiaoqing Pan*. “Observation of Grain Boundary Electrostatic Characteristics in Perovskite Solid-State Electrolytes by Four-Dimensional Scanning Transmission Electron Microscopy”