Communication—Atomic Layer Deposition of Aluminum Fluoride for Lithium Metal Anodes

Rechargeable lithium metal anodes are contenders to supplant carbon anodes, but because of their thermodynamic instability the kinetic stability afforded by solid electrolyte interphase (SEI) layer formed in situ is crucial. Unlike graphite, a stable SEI that facilitates charge transfer is rarely formed on Li in any electrolyte, and requires an "engineered" interface. The interfacial stability of Li can be improved in both liquid and solid electrolytes by thin coatings of AlF3 using atomic layer deposition. Its method of deposition and its efficacy to protect Li in acetonitrile, and improve specific capacity and cycle life of lithium-sulfur cells are described. (C) 2020 Not subject to copyright in the USA. Contribution of NASA Jet Propulsion Laboratory.