Novel ALD Chemistry Enabled Low-Temperature Synthesis of Lithium Fluoride Coatings for Durable Lithium Anodes

• DOI: 10.1021/acsami.8b04573
• Publication Date: 2018-07-09T21:56:05Z
• Authors: Lin Chen; Kan-Sheng Chen; Xinjie Chen; Giovanni Ramirez; Zhennan Huang; Natalie R. Geise; Hans-Georg Steinrück; Brandon L. Fisher; Reza Shahbazian-Y...; Michael F. Toney; Mark C. Hersam; Jeffrey W. Elam
• Keywords: Lithium fluoride; Conformal coating

Lithium metal anodes can largely enhance the energy density of rechargeable batteries because high theoretical capacity and negative potential. However, problem lithium dendrite formation low Coulombic efficiency (CE) during electrochemical cycling must be solved before widely deployed. Herein, a new atomic layer deposition (ALD) chemistry to realize low-temperature synthesis homogeneous stoichiometric fluoride (LiF) is reported, which then for first time, as far we know, deposited directly onto metal. The LiF preparation performed at 150 °C yielding 0.8 Å/cycle. films are found crystalline, highly conformal, with purity levels >99%. Nanoindentation measurements demonstrate achieving shear modulus 58 GPa, 7 times higher than sufficient value resist dendrites. When used protective coating on lithium, it enables stable 99.5% over 170 cycles, about 4 longer that bare anodes. remarkable battery performance attributed nanosized serves two critical functions simultaneously: (1) dielectric creates uniform current distribution excellent stripping/plating ultrahigh mechanical strength suppress dendrites; (2) great stability electrolyte isolation by pure prevents parasitic reactions much improved CE. This ALD conformal not only offers promising avenue implement high-capacity but also paves way future studies investigate failure evolution mechanisms solid interphase (SEI) using our such graphite, silicon, lithium.