Electrochemically and Thermally Stable Inorganics–Rich Solid Electrolyte Interphase for Robust Lithium Metal Batteries

Abstract Severe dendrite growth and high‐level activity of the lithium metal anode lead to a short life span and poor safety, seriously hindering the practical applications of lithium metal batteries. With a trisalt electrolyte design, an F‐/N‐containing inorganics–rich solid electrolyte interphase on a lithium anode is constructed, which is electrochemically and thermally stable over long‐term cycles and safety abuse conditions. As a result, its Coulombic efficiency can be maintained over 98.98% for 400 cycles. An 85.0% capacity can be retained for coin‐type full cells with a 3.14 mAh cm −2 LiNi 0.5 Co 0.2 Mn 0.3 O 2 cathode after 200 cycles and 1.0 Ah pouch‐type full cells with a 4.0 mAh cm −2 cathode after 72 cycles. During the thermal runaway tests of a cycled 1.0 Ah pouch cell, the onset and triggering temperatures were increased from 70.8 °C and 117.4 °C to 100.6 °C and 153.1 °C, respectively, indicating a greatly enhanced safety performance. This work gives novel insights into electrolyte and interface design, potentially paving the way for high‐energy‐density, long‐life‐span, and thermally safe lithium metal batteries.