Silver-Carbon Composite Interlayers for "Anodeless" Solid-State Batteries

Lithium-free so-called “anodeless” solid-state batteries promise to deliver high cell energy densities. However, at charge rates on the order of 1 mA cm^-2, plating of Li at the current collector/solid electrolyte interface is highly inhomogeneous, and dendrites (filaments of Li metal) are observed to penetrate through the solid electrolyte resulting in cell failure. Recent work has suggested that introduction of a silver-carbon composite interlayer between the solid electrolyte and current collector can protect the solid electrolyte against dendrite growth whilst promoting more homogeneous deposition of Li metal.¹ In this work, we investigate silver-carbon composite interlayers, revealing the structural changes within the interlayer during charge and discharge, and the rate dependency of these changes. We go on to investigate the homogeneity of Li-Ag alloy and Li metal formation at the current collector with and without silver nanoparticles present in the interlayer, and how this affects the processes of charge and discharge. We demonstrate dendrite-free charge at 2 mA cm^-2 and reveal the origin of the failure of the interlayer at higher rates.²<br/><br/>1. Lee et al., High energy long-cycling all-solid-state lithium metal batteries enabled by silver–carbon composite anodes. Nat. Energy 5, 299–308 (2020)<br/>2. Spencer-Jolly et al., Structural changes in the silver-carbon composite anode interlayer of solid-state batteries, Joule 7, 503–514 (2023)