Role of interlayers in Na plating process of zero-excess solid-state batteries using an operando virtual electrode-LEEM approach

This proposal aims to be the continuation of the research conducted in the framework of OPERA project on zero-excess solid-state batteries (ZESSBs). ALBA part of the project is dedicated to the LEEM/PEEM characterization of the alkali Na (or Li) anode and electrolyte-anode interface during in-situ nucleation and growth. In the virtual electrode (VE)-LEEM method during the anode plating (corresponding to battery charging) an area of the surface is irradiated with an electron beam (coming from LEEM gun) with the diameter of 100 µm. The virtual anode technique circumvents issues related to the physical current collector by creating a surface negative charge, which then promotes the cation migration and the formation of metallic Na/Li clusters on the electrolyte surface. The VE-LEEM method combined with the PEEM spectro-microscopy offers insight into the early-stage nucleation, revealing the influence of the various experimental parameters impacting the anode morphology and growth efficiency. During the previous ALBA beamtimes on this topic we succeeded to conduct the systematic characterization of the Na and Li anode growth onto an electrolyte surface in NaGdSiO/Na and LLZTO/Li bulk systems, with the dependence on variable parameters. Our current research is focused on the modification of the anode growth mode by the use of interlayers of different metals: Mg, Ag or Au on both Na- and Li-based systems. The main objective of this beamtime is further examination of how seed Mg and Ag interlayers, prepared via the developed shadow-mask technique, influence the nucleation and growth modes of Na anodes on the surface of Na-based SSE and in the end improvement of the nucleation habit by optimizing the material, its thickness and electron irradiation parameters.