Polymeric Coating on Lithium Metal Surface for the Stabilization of Electrode-Electrolyte Interface

Abstract

Lithium (Li) metal is believed as a promising anode material taking over the conventional graphite, because of the higher energy density. However, non-uniform electroplating (dendrite growth) of Li metal leads to a short circuit inside the battery and hinders Li metal battery from the practical use. The dendrite growth is often resulted from uneven flux of Li cation near the surface of the Li metal. Here we present the design and the constructing methods of polymeric coating on the Li metal to regulate the ion flux and stabilize the electrode-electrolyte interface. The methods include; (1) in situ formation of soft and rigid solid electrolyte interface (SEI) layer composed of poly(vinylene carbonate) (polyVC) and lithium carbonate (Li2CO3); (2) the direct polymerization of polyVC on Li metal surface. The method (1) also focuses on the study of cycle life of Li metal under fluorine-free environment by using lithium iodide (LiI) as the lithium salt. The method (2) enables the direct formation of an uniform and dense polymeric layer on Li metal in a scalable fashion.