3D Asymmetric Bilayer Garnet-Hybridized High-Energy-Density Lithium-Sulfur Batteries

Published

January 11, 2023

Author(s)

Changmin Shi, Tanner Hamann, Saya Takeuchi, George Alexander, Adelaide M. Nolan, Matthew Limpert, Zhezhen Fu, Jonathan O'Neill, Griffin Godbey, Joseph A. Dura, Eric Wachsman

Abstract

Lithium garnet Li₇La₃Zr₂O₁₂ (LLZO) with high ionic conductivity and chemical stability against a Li metal anode is considered one of the most promising solid electrolytes for lithium-sulfur batteries. However, an infinite charge time resulting in low capacity has been observed in Li-S cells using Ta-doped LLZO (Ta-LLZO) as a solid electrolyte. It was observed that this cell failure is corelated with lanthanum segregation to the surface of Ta-LLZO that reacts with sulfur cathode. We demonstrated this correlation by using lanthanum excess and lanthanum deficient Ta-LLZO as the solid electrolyte in Li-S cells. To resolve this challenge, we physically separated the sulfur cathode and LLZO using a poly(ethylene oxide) (PEO)-based buffer interlayer. With a thin bilayer LLZO and the stabilized sulfur cathode/LLZO interface, the hybridized Li-S batteries achieved a high initial discharge capacity of 1307 mAh/g corresponding to an energy density of 639 Wh/L and 134 Wh/kg under a high current density of 0.2 mA/cm2 at room temperature without any indication of a polysulfide shuttle. By simply reducing the LLZO dense layer thickness to 10 μm as we have demonstrated before, a significantly higher energy density of 1308 Wh/L and 257 Wh/kg is achievable. X-ray Diffraction and X-ray Photoelectron Spectroscopy indicate that the PEO-based interlayer which physically separates the sulfur cathode and LLZO, is both chemically and electrochemically stable with LLZO. In addition, the PEO-based interlayer can adapt to the stress/strain associated with sulfur volume expansion during lithiation.

Citation

ACS Applied Materials and Interfaces

Volume

15

Issue

1

Pub Type

Journals

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DOI Link

Keywords

: Li-S battery, 3D bilayer LLZO electrolyte structure, high energy density, high mass loading, stable cathode/solid electrolyte interface

Citation

Shi, C. , Hamann, T. , Takeuchi, S. , Alexander, G. , Nolan, A. , Limpert, M. , Fu, Z. , O'Neill, J. , Godbey, G. , Dura, J. and Wachsman, E. (2023), 3D Asymmetric Bilayer Garnet-Hybridized High-Energy-Density Lithium-Sulfur Batteries, ACS Applied Materials and Interfaces, [online], https://dx.doi.org/10.1021/acsami.2c14087 (Accessed May 1, 2024)