Ex situ poly-DOL coatings for lithium metal protection†

Lithium metal is a promising anode material candidate for next-generation high energy density batteries owing to its high theoretical specific capacity and low electrochemical potential. However, rapid capacity fade and safety issues due to inhomogeneous deposition and side reaction between lithium and electrolyte are the main hindrance to the successful utilization of the lithium metal anode. As a solid electrolyte interphase (SEI) plays an important role in lithium stripping and deposition, we propose a multi-component, organic–inorganic composite artificial SEI formed by ring-opening polymerization of 1,3-dioxolane (DOL) with incorporation of inorganic salt additives. The formed poly-DOL can provide a robust and flexible organic matrix which confines the reduction of other components to form a composite SEI and protect the lithium metal anode to improve the cycle stability of a lithium metal battery. The composition of this SEI layer is designed towards employing the coated layer for lithium metal anodes in carbonate-based and ether-based electrolyte systems. This work provides an alternative approach to effectively protect the lithium electrode before cycling in a battery.