Grain boundary complexion modification for interface stability in garnet based solid-state Li batteries

• Published in: Journal of power sources 2024-05, Vol.602, p.234394, Article 234394
• Main Authors: Wang, Chih-Chieh, Hsu, Wei-Chun, Chang, Chia-Yu, Ihrig, Martin, Thuy Tran, Ngoc Thanh, Lin, Shih-kang, Windmüller, Anna, Tsai, Chih-Long, Eichel, Rüdiger-A., Chiu, Kuo-Feng
• Format: Article
• Language: English
• Subjects: Al2O3; Atomic layer deposition; Garnet type LLZO; Solid-state electrolyte
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2024.234394

The garnet type solid-state electrolyte (SSE) encounters challenges related to poor interfacial contact with Li metal and dendrite penetration problem. This study addresses these issues by manipulating the surface property of garnet-based LLZTO (Li6.5La3Zr1.6Ta0.4O12) SSE. The manipulation is achieved by varying thickness of Al2O3 atomic layer deposition (ALD), followed by sintering. Research results show that the relative density, ionic conductivity, and hardness of LLZTO are improved while electronic conductivity is reduced due to the formation of multiple complexions at grain boundary (GB). The SSE pellets also demonstrate improved wettability with Li metal, leading to stable galvanostatic Li plating/stripping cycling with low polarization, which allows for batter battery performance than pristine one. The concept of modifying SSE through the grain boundary complexion modification by thin ALD coating for enhancing the dendrite tolerance with better electrochemical properties of SSE may open a new direction for solid state battery research. •Grain boundary complexion modification by thin ALD Al2O3 coating.•Improved mechanical properties and ionic conductivities of the LLZTO pellet.•Improved Li wettability and dendrite tolerance for enhanced performances.