Lithium surface engineering with in-situ generated Fe/Li2O/LiCl mixed electron/ion conductive layer for stable lithium metal batteries

The lithium metal batteries (LMBs) using metallic Li as anode with high-energy density have been prevailed in the field of energy storage, while the aggregation of Li dendrites and brittle solid state electrolyte interface (SEI) impede the development of Li anode. In this work, to regulate the interface of Li anode, a Fe/Li 2 O/LiCl mixed electron/ion conducting layer is in-situ generated on the surface of Li anode, which is derived from the electrochemical reaction between Li anode and Fe 2 O 3 /FeOCl coatings on commercial separator. The synergistic effect between electron conductive Fe and ion conductive Li 2 O/LiCl is beneficial to build up dense and uniform SEI and promote uniform Li + flux, resulting in smooth Li deposition, which will further stabilize the Li metal surface and prolong the battery life of LMBs. Specifically, the symmetric Li||Li cells with Fe 2 O 3 /FeOCl can operate steadily for 600 h at 1 mAh cm −2 without obvious voltage polarization, and the corresponding full battery matched with S-PAN delivers capacity retention of 64.43 % at 500 mA g −1 after 350 cycles.