Department of Energy EngineeringDesign of catalyst support for high durability of oxygen electrocatalystPlating-stripping reversibility of lithium metal was improved by reinforcing the solid-electrolyte interphase (SEI) layer by inorganic nanobeads during formation of the SEI layer. The outmost SEI shell (OSS) was clearly identified, which is the SEI layer formed on current collectors (or lithium metal) before the first lithium metal deposition. The OSS was intrinsically brittle and fragile so that the OSS was easily broken by lithium metal dendrites growing along the progress of plating. Lithium metal deposit was not completely stripped back to lithium ions. On the other hand, lithium metal cells containing inorganic nanobeads in electrolyte showed high reversibility between plating and stripping. The nanobeads were incorporated into the OSS during the OSS formation. The nanobead-reinforced OSS having mechanically durable toughness suppressed dendritic growth of lithium metal, not allowing the dendrites to penetrate the OSS. In addition to the mechanical effect of nanobeads, the LiF-rich SEI layer formation was triggered by HF generated by the reaction of the moisture adsorbed on oxide nanobeads with PF6-. The LiF-rich composition was responsible for facile lithium ion transfer through the SEI layer and the OSS in the presence of nanobeads.clos
