Stabilization of lithium metal anodes using silane-based coatings

For energy storage systems that use a charged cathode, the source of lithium is typically lithium metal. For several high energy systems under study, notably those that utilize elemental sulfur or oxygen (air) as the cathode, their very high capacity makes lithium metal anodes essential. In this study we evaluated the cycling performance of a series of silane-based coatings formed on a cleaned lithium metal surface before exposure to electrolyte. These substituted silane (R3Si-) based coatings are formed from the self-terminating reaction of the R3Si-Cl with lithium surface hydroxyl groups. The cycling performance of a trimethyl silyl coated surface and a triisopropyl silyl coated surface were compared to an uncoated sample and the results explained by a combination of surface coverage density and the ability of the coating to inhibit free solvent attack of the metal electrode surface.

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► New stable conformal coatings on lithium metal.
► Significant enhancement of cycle life in electrochemical cells.
► Solvent exclusion and size of R-groups on coatings plays key role in enhancement.