Lithiation Gradients and Tortuosity Factors in Thick NMC111-Argyrodite Solid-State Cathodes

Alyssa M Stavola; Xiao Sun; Dominick P Guida; Andrea M Bruck; Daxian Cao; John S Okasinski; Andrew C Chuang; Hongli Zhu; Joshua W Gallaway

doi:10.1021/acsenergylett.2c02699

Lithiation Gradients and Tortuosity Factors in Thick NMC111-Argyrodite Solid-State Cathodes

ACS Energy Lett. 2023 Feb 2;8(2):1273-1280. doi: 10.1021/acsenergylett.2c02699. eCollection 2023 Feb 10.

Authors

Alyssa M Stavola¹, Xiao Sun², Dominick P Guida¹, Andrea M Bruck¹, Daxian Cao², John S Okasinski³, Andrew C Chuang³, Hongli Zhu², Joshua W Gallaway¹

Affiliations

¹ Department of Chemical Engineering, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts02115, United States.
² Department of Mechanical and Industrial Engineering, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts02115, United States.
³ X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois60439, United States.

Abstract

Achieving high energy density in all-solid-state lithium batteries will require the design of thick cathodes, and these will need to operate reversibly under normal use conditions. We use high-energy depth-profiling X-ray diffraction to measure the localized lithium content of Li_1-xNi_1/3Mn_1/3Co_1/3O₂ (NMC111) through the thickness of 110 μm thick composite cathodes. The composite cathodes consisted of NMC111 of varying mass loadings mixed with argyrodite solid electrolyte Li₆PS₅Cl (LPSC). During cycling at C/10, substantial lithiation gradients developed, and varying the NMC111 loading altered the nature of these gradients. Microstructural analysis and cathode modeling showed this was due to high tortuosities in the cathodes. This was particularly true in the solid electrolyte phase, which experienced a marked increase in tortuosity factor during the initial charge. Our results demonstrate that current distributions are observed in sulfide-based composites and that these will be an important consideration for practical design of all-solid-state batteries.