Elastic Modulus,Hardness,and Fracture Toughness of Li6.4La3Zr1.4Ta0.6O12 Solid Electrolyte

• 作者: Shan Hu Pengyu Xu Luize Scalco de Vasconcelos Lia Stanciu Hongwei Ni Kejie Zhao
• 来源期刊: 中国物理快报（英文版）
• 年，卷（期）: 2021,（9）
• 所属期刊栏目: CROSS-DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY
• 页码范围: 158-168
• 页数: 11页
• 语种: 英文
• DOI: 10.1088/0256-307X/38/9/098401

摘要

Li6.4La3Zr1.4Ta0.6O12(LLZTO)is a promising inorganic solid electrolyte due to its high Li+conductivity and electrochemical stability for all-solid-state batteries.Mechanical characterization of LLZTO is limited by the synthesis of the condensed phase.Here we systematically measure the elastic modules,hardness,and fracture toughness of LLZTO polycrystalline pellets of different densities using the customized environmental nanoin-dentation.The LLZTO samples are sintered using the hot-pressing method with different amounts of Li2CO3 additives,resulting in the relative density of the pellets varying from 83％to 98％and the largest grain size of 13.21±5.22 μm.The mechanical properties show a monotonic increase as the sintered sample densifies,elastic modulus and hardness reach 158.47±10.10 GPa and 11.27±1.38 GPa,respectively,for LLZTO of 98％density.Similarly,fracture toughness increases from 0.44 to 1.51 MPa·m1/2,showing a transition from the intergranular to transgranular fracture behavior as the pellet density increases.The ionic conductivity reaches 4.54×10-4 S/cm in the condensed LLZTO which enables a stable Li plating/stripping in a symmetric solid-state cell for over 100 cycles.This study puts forward a quantitative study of the mechanical behavior of LLZTO of different microstructures that is relevant to the mechanical stability and electrochemical performance of all-solid-state batteries.