(Invited) Interfacial Engineering of Solid-State Batteries: Coupled Electrochemical, Morphological, and Mechanical Evolution
Authors: Dasgupta Neil P. 
Published: December 2020

Solid-state batteries have seen a dramatic increase in research in recent years because of their ability to address safety challenges associated with flammable liquid electrolytes, and the potential to enable Li metal anodes. However, all solid-state interfaces present unique challenges, including high interfacial impedances, accommodation of mechanical stresses due to solid-solid interfacial contact, and (electro)chemical instabilities that can evolve during dynamic cycling conditions1.

To address these challenges, our group focuses on gaining new fundamental insights into the coupled phenomena occurring at interfaces, and applies this knowledge to rationally design interfacial composition and structure to address the root cause of performance limitations. In this talk, I will first present a multi-modal in situ/operando characterization approach to study Li metal-solid electrolyte interfaces during cycling2-4. Mechanistic insight will be provided into solid-electrolyte interphase (SEI) evolution, as well as nucleation and growth dynamics of the Li metal anode during cycling. In addition to these coupled morphological/chemical/electrochemical phenomena, the unique mechanical properties of Li metal will be discussed in the context of solid-state battery interfaces4-5.

Equipped with this fundamental knowledge, I will describe the rational design of interlayers at the Li metal-SE interface using Atomic Layer Deposition (ALD). Examples will be presented in both bulk solid-state battery interfaces, and thin film electrolytes deposited by ALD3,6-7. Through this interdisciplinary approach of fundamental materials chemistry and applied engineering, strategies to address future interfacial challenges will be addressed, pointing towards rational design and manufacturing of optimized interfaces.

1) K. B. Hatzell, X. C. Chen, C. L. Cobb, N. P. Dasgupta, M. B. Dixit, L. E. Marbella, M. T. McDowell, P. P. Mukherjee, A. Verma, V. Viswanathan, A. S. Westover, W. G. Zeier “Challenges in Lithium Metal Anodes for Solid State Batteries” ACS Energy Lett.
5, 922 (2020).

2) Gupta, E. Kazyak, N. Craig, J. Christensen, N. P. Dasgupta, J. Sakamoto, “Evaluating the Effects of Temperature and Pressure on Li/PEO-LiTFSI Interfacial Stability and Kinetics” J. Electrochem. Soc.
165, A2801 (2018).

3) A. L. Davis, R. Garcia-Mendez, K. N. Wood, E. Kazyak, K.-H. Chen, G. Teeter, J. Sakamoto, N. P. Dasgupta “Electro-Chemo-Mechanical Evolution of Sulfide Solid Electrolyte/Li Metal Interfaces: Operando Analysis and ALD Interlayer Effects” J. Mater. Chem. A
8, 6291 (2020).

4) E. Kazyak, R. Garcia-Mendez, W. S LePage, A. Sharafi, A. L. Davis, A. J. Sanchez, K.-H. Chen, C. Haslam, J. Sakamoto, N. P. Dasgupta “Li Penetration in Ceramic Solid Electrolytes: Operando Microscopy Analysis of Morphology, Propagation, and Reversibility” Matter
2, 1 (2020).

5) W. S. LePage, Y. Chen, E. Kazyak, K.-H. Chen, A. J. Sanchez, A. Poli, E. M. Arruda, M. D. Thouless, N. P. Dasgupta “Lithium Mechanics: Roles of Strain Rate and Temperature and Implications for Lithium Metal Batteries” J. Electrochem. Soc.
166, A89 (2019).

6) E. Kazyak, K.-H. Chen, K. N. Wood, A. L. Davis, T. Thompson, A. J. Sanchez, X. Wang, C. Wang, J. Sakamoto, N. P. Dasgupta, “Atomic Layer Deposition of the Solid Electrolyte Garnet Li7La3Zr2O12” Chem. Mater.
29, 3785 (2017).

7) E. Kazyak, K.-H. Chen, A. L. Davis, S. Yu, A. J. Sanchez, J. Lasso, A. R. Bielinski, J. Sakamoto, D. J. Siegel, N. P. Dasgupta, “Atomic Layer Deposition and First Principles Modeling of Glassy Li3BO3-Li2CO3 Electrolytes for Solid-State Li Metal Batteries” J. Mater. Chem. A
6, 19425 (2018).