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Unraveling the Li Penetration Mechanism in Polycrystalline Solid Electrolytes
Author(s) -
Tantratian Karnpiwat,
Yan Hanghang,
Ellwood Kevin,
Harrison Elisa T.,
Chen Lei
Publication year - 2021
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.202003417
Subject(s) - materials science , penetration (warfare) , crystallite , nucleation , elastic modulus , composite material , grain boundary , ceramic , penetration depth , microstructure , electron , electrolyte , chemical physics , thermodynamics , metallurgy , electrode , chemistry , optics , physics , operations research , quantum mechanics , engineering
Lithium dendrite penetration has been widely evidenced in ceramic solid electrolytes (SEs), which are expected to suppress Li dendrite formation due to their ultrahigh elastic modulus. This work aims to reveal the mechanism of Li penetration in polycrystalline SEs through electro‐chemo‐mechanical phase‐field model, using Li 7 La 3 Zr 2 O 12 (LLZO) as the model material. The results show the Li penetration patterns are influenced by both mechanical and electronic properties of the microstructures, i.e., grain boundaries (GBs). Li nucleates at the GB junctions on the Li/SE interface and propagates along the GB, at which the interfacial compressive stress is small due to the GB softening. Moreover, the excess trapped electrons at the GB may trigger isolated Li nucleation sites, abruptly increasing the Li penetration depth. High‐throughput simulations yield a phase map of Li penetration patterns under different trapped electrons concentrations and GB/grain elastic modulus mismatch. The map can quantitatively inform whether the mechanical or electronic properties dominate Li penetration morphologies, providing a strategy for the design of improved SE materials.