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Mesoscopic Framework Enables Facile Ionic Transport in Solid Electrolytes for Li Batteries
Author(s) -
Ma Cheng,
Cheng Yongqiang,
Chen Kai,
Li Juchuan,
Sumpter Bobby G.,
Nan CeWen,
More Karren L.,
Dudney Nancy J.,
Chi Miaofang
Publication year - 2016
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201600053
Subject(s) - mesoscopic physics , materials science , electrolyte , ionic conductivity , fast ion conductor , ionic bonding , percolation (cognitive psychology) , nanotechnology , ion , chemical physics , electrical conductor , conductivity , electrode , condensed matter physics , physics , chemistry , composite material , neuroscience , biology , quantum mechanics
Li‐ion‐conducting solid electrolytes can simultaneously overcome two grand challenges for Li‐ion batteries: the severe safety concerns that limit the large‐scale application and the poor electrolyte stability that forbids the use of high‐voltage cathodes. Nevertheless, the ionic conductivity of solid electrolytes is typically low, compromising the battery performances. Precisely determining the ionic transport mechanism(s) is a prerequisite for the rational design of highly conductive solid electrolytes. For decades, the research on this subject has primarily focused on the atomic and microscopic scales, where the main features of interest are unit cells and microstructures, respectively. Here, it is shown that the largely overlooked mesoscopic scale lying between these extremes could be the key to fast ionic conduction. In a prototype system, (Li 0.33 La 0.56 )TiO 3 , a mesoscopic framework is revealed for the first time by state‐of‐the‐art scanning transmission electron microscopy. Corroborated by theoretical calculations and impedance measurements, it is demonstrated that such a unique configuration maximizes the number of percolation directions and thus most effectively improves the ionic conductivity. This discovery reconciles the long‐standing structure–property inconsistency in (Li 0.33 La 0.56 )TiO 3 and also identifies mesoscopic ordering as a promising general strategy for optimizing Li + conduction.