Argyrodite Solid-State Electrolytes: Overcoming Barriers to Interfacial Stability for Advanced Manufacturing of Solid-State Batteries

Lithium argyrodite solid-state electrolytes (SSEs) exhibit many desirable properties such as high ionic conductivity (&gt;1 mS/cm) at room temperature^1,2,3 and greater ductility than most oxide SSEs,² enabling roll-to-roll cell fabrication relevant for EV battery packs. However, their instability in ambient air and at the Li||SSE and cathode||SSE interfaces presents challenges for scaled production and limits their cell performance.^3,4 In this presentation, we present two interfacial strategies – those that involve dopants as well as pseudocapacitive interlayers – to overcome interfacial stability issues associated with argyrodite-type SSEs (Li₆PS₅Cl) in solid-state batteries. By using zinc, oxygen, and chlorine as dopants, we show that members within the Li_6-2x-yZn_xPS_5-x-yO_xCl_1+y(x ≤ 0.25, y ≤ 0.25) phase space exhibit reduced reactivity under dry and H₂O-saturated oxygen as well as improved room temperature symmetric cell cycling performance at relatively high capacity and current densities. We also demonstrate a scalable, liquid-phase processing method for spraying adhesive pseudocapacitive interlayers on copper current collectors. These interlayers, constructed of MXenes (Ti₃C₂<i>T_x</i>) decorated with metal nanoparticles, can regulate the morphology of lithium metal during plating and stripping. Both strategies take advantage of Li alloy formation at the Li||SSE interface to form beneficial decomposition products that improve cycling performance and enhance the stability of the SSE with Li metal anodes as shown in recent work.⁵ Development of high performance next-generation solid-state batteries, those envisioned for EVs, will require interfacial tailoring, such as those presented in this work, in order to reduce impedance, alleviate poor rate performance, and reduce side reactions that lead to capacity fade.<br/><br/><b>Acknowledgements:</b><br/>This project was supported by Laboratory Directed Research and Development (LDRD) funding from Argonne National Laboratory, provided by the Director, Office of Science, of the U.S. Department of Energy under Contract No. DE-AC02-06CH11357. This research used resources of the Center for Nanoscale Materials, U.S. Department of Energy (DOE) Office of Science user facilities operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. U.D.E. was supported by the Department of Defense (DoD) through the National Defense Science & Engineering Graduate (NDSEG) Fellowship Program as well as the Quad Fellowship. The authors gratefully acknowledge Natalie Holzwarth and David Cory Lynch for their modeling work of the Li_6-2x-yZn_xPS_5-x-yO_xCl_1+y system.<br/><br/><b>References:</b><br/>¹L. Zhou, N. Minafra, W. G. Zeier, and L. F. Nazar. “Innovative Approaches to Li-Argyrodite Solid Electrolytes for All-Solid-State Lithium Batteries” <i>Acc. Chem. Res.</i> (2021)<br/>²Z. Zhang, Y. Shao, B. Lotsch, Y. Hu, H. Li, J. Janek, L. F. Nazar, C. Nan, J. Maier, M. Armand, and L. Chen. “New horizons for inorganic solid state ion conductors” <i>Energy Environ. Sci.</i> (2018)<br/>³T. Schmaltz, F. Hartmann, T. Wicke, L. Weymann, C. Neef, J. Janek. “A Roadmap for Solid-State Batteries” <i>Adv. Energy Mater.</i> (2023)<br/>⁴K. T. Kim, J. Woo, Y. Kim, S. Sung, C. Park, C. Lee, Y. J. Park, H. Lee, K. Park, and Y. S. Jung “Ultrathin Superhydrophobic Coatings for Air-Stable Inorganic Solid Electrolytes: Toward Dry Room Application for All-Solid-State Batteries” <i>Adv. Energy Mater.</i> (2023)<br/>⁵Z. D. Hood, A. U. Mane, A. Sundar, S. Tepavcevic, P. Zapol, U. D. Eze, S. P. Adhikari, E. Lee, G. E. Sterbinsky, J. W. Elam, and J. G. Connell. “Multifunctional Coatings on Sulfide-Based Solid Electrolyte Powders with Enhanced Processability, Stability, and Performance for Solid-State Batteries” <i>Adv. Mater.</i> (2023)