Structural changes in the silver-carbon composite anode interlayer of solid-state batteries

Ag-carbon composite interlayers have been reported to enable Li -free (anodeless) cycling of solid-state batteries. Here, we report structural changes in the Ag-graphite interlayer, showing that on charge, Li intercalates electrochemically into graphite, subse-quently reacting chemically with Ag to form Li-Ag alloys. Discharge is not the reverse of charge but rather passes through Li-deficient Li-Ag phases. At higher charging rates, Li intercalation into graphite outpaces the chemical reactions with Ag, delaying the formation of the Li-Ag phases and resulting in more Li metal deposition at the current collector. At and above 2.5 mA center dot cm-2, Li dendrites are not suppressed. Ag nanoparticles do not suppress dendrites more effectively than does an interlayer of graphite alone. Instead, Ag in the carbon interlayer results in more homogeneous Li and Li-Ag formation on the current collector during charge.

Automated summary

Ag-carbon composite interlayers have been proven effective in enabling Li-free cycling of solid-state batteries. Li intercalates electrochemically into graphite on charge, subsequently reacting chemically with Ag to form Li-Ag alloys. Discharge does not reverse this process, instead passing through Li-deficient Li-Ag phases. At higher charging rates, Li intercalation outpaces chemical reactions with Ag, resulting in delayed Li-Ag phase formation and increased Li metal deposition at the current collector. Li dendrites are not suppressed at and above 2.5 mA•cm-2, and Ag nanoparticles are not more effective than a graphite interlayer. Instead, Ag in the carbon interlayer promotes more uniform Li and Li-Ag formation during charge.