Stabilization of Li7La3Zr2O12 Solid Electrolyte through Ga-Based Precipitates and the Ga–Au Surface Layer

Garnet-type Li7La3Zr2O12 (LLZO) is a promising oxide solid electrolyte with high ionic conductivity and excellent stability toward Li metal. However, the presence of grain boundaries (GBs) causes a decrease in the ionic conductivity and cycling stability of the sintered LLZO. Herein, we promote the...

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Bibliographic Details
Published in:International journal of energy research 2024-03, Vol.2024, p.1-15
Main Authors: Kim, Dohun, Nguyen, Minh Hai, Chun, Seung Hoon, Jeon, June, Kim, Byung-Kook, Park, Sangbaek
Format: Article
Language:English
Subjects:
Atoms & subatomic particles
Batteries
Conductivity
Contact angle
Contact resistance
Cycles
Electrolytes
Garnet
Grain boundaries
High temperature
Investigations
Ion currents
Metals
Polyvinyl alcohol
Precipitates
Precipitation
Relative density
Sintering
Solid electrolytes
Specific gravity
Spectrum analysis
Stability
Surface layers
Synergistic effect
Thickness
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Summary:Garnet-type Li7La3Zr2O12 (LLZO) is a promising oxide solid electrolyte with high ionic conductivity and excellent stability toward Li metal. However, the presence of grain boundaries (GBs) causes a decrease in the ionic conductivity and cycling stability of the sintered LLZO. Herein, we promote the Ga precipitation at GBs through excessive doping with Ga/Al/Ta, simultaneously depositing a few nanometers thickness Au layer to form a Ga–Au surface layer. High-temperature sintering of heavily doped LLZO induces Ga precipitation, effectively filling the GB of the pellet. Consequently, the relative density and ionic conductivity are increased. Furthermore, nanoscale Au encounters precipitated Ga and forms a new Ga–Au layer, which reduces the contact resistance. The new layer prevents direct contact between molten Li and Ga-based composites at the GBs, thus enhancing the cycling stability. Therefore, it demonstrates the synergistic effect that the precipitated Ga improves the compactness of the LLZO electrolyte, whereas the Ga–Au layer enhances the cycling stability. It provides a straightforward approach to address the issues originated from GBs and increase the cycling stability of LLZO, thereby contributing to the practical application of all-solid-state batteries.
ISSN:0363-907X
1099-114X
DOI:10.1155/2024/9050890