Stable Lithium Metal Anodes with a GaO Artificial Solid Electrolyte Interphase in Damp Air

As a promising high energy density electrode material for rechargeable batteries, lithium (Li) metal is still suffering from air/water instability due to its highly reactive nature. In addition, the Li dendrite issue in Li metal batteries needs to be resolved to ensure the safety of batteries and for wide applications. Herein, we demonstrate that a simple compact GaO layer formed using liquid metal (LM) can act as an artificial solid electrolyte interphase to block moisture and oxygen in the air from corroding the lithium metal. Interestingly, GaO that covered the electrode effectively inhibits Li dendrite growth in electrochemistry cycling, ensuring the safety of Li metal batteries. The exposed composite Li metal anode (exposed under ambient air with relative humidity (RA) ≈ 75% for 5 h) not only shows a superior stability (symmetrical cell) but also delivers an elevated cycling stability (>500 cycles at 0.5 and 1 C) with a sulfur@C cathode in the full-cell configuration. Our work provides a new pathway for the large-scale applications of the air/water-tolerant Li metal anode in rechargeable batteries.