Atomistic origin of high grain boundary resistance in solid electrolyte lanthanum lithium titanate  

作　　者：Shang Peng Yongjin Chen Xuefeng Zhou Mingxue Tang Jianbo Wang Hua Wang Lin Guo Lujun Huang Wenge Yang Xiang Gao 

机构地区：[1]Center for High Pressure Science and Technology Advanced Research(HPSTAR),Beijing,100094,China [2]School of Physics and Technology,Center for Electron Microscopy,MOE Key Laboratory of Artificial Micro-and Nano-structures,and Institute for Advanced Studies,Wuhan University,Wuhan,430072,China [3]School of Chemistry,Beijing Advanced Innovation Center for Biomedical Engineering,Beihang University,Beijing,100191,China [4]School of Materials Science and Engineering,Harbin Institute of Technology,P.O.Box 433,Harbin,150001,China

出　　处：《Journal of Materiomics》2024年第6期1214-1221,共8页无机材料学学报（英文）

基　　金：This work was supported by the National Natural Science Foundation of China(U2030206,22075003).

摘　　要：Lanthanum lithium titanate is one of the promising electrolytes for solid-state lithium-ion batteries due to its high bulk ionic conductivity up to∼10^(−3) S/cm.However,the practical application of this material has been bottlenecked by high grain boundary(GB)resistance,while the underlying mechanism is still under debate.Here we report a comprehensive study with direct evidence to reveal the origin of high GB resistance in La_(2/3)–xLi_(3x)TiO_(3)(LLTO).Atomic-scale observations via advanced scanning transmission electron microscopy show that the GBs are uniformly subject to subsurface segregation of La atoms to compensate for the excess surface charges.The La segregation leads to an abrupt decrease of charge carrier concentration neighboring GBs and hence is supposed to have deleterious effect on GB conductivity.The findings suggest a novel mechanism of space-charge-induced cation segregation,which shed lights on the intrinsic origin of low GB ionic conductivity in LLTO.

关 键 词：SPACE-CHARGE layer CATION segregation Intergranullar GLASSY film Solid-state electrolyte Ionic conductivity 

分 类 号：TM912[电气工程—电力电子与电力传动]