Lithium metal batteries have become potential high-energy storage devices because lithium metal has excellent theoretical capacity and low reduction potential. Unfortunately, the reckless growth of lithium dendrites leads to the decrease in Coulombic efficiency and the attenuation of cycle performance. Herein, we propose a collaborative assembly approach for a fluorine-enriched heterostructured solid electrolyte interphase (SEI) on lithium metal to enable stable and ultralong-life lithium metal batteries. The fluorine-enriched heterostructured SEI consists of an artificial precursor substrate K2ZrF6 and an epigenetically assembled LiF layer, and the composite structure cooperatively realizes the rapid conduction of Li+ ions and inhibits the formation of lithium dendrites. Benefiting from the heterostructured SEI, the symmetric cell exhibits an ultralong-time stable cycle of more than 7000 h at a high current and capacity density (4 mA cm-2 and 4 mA h cm-2, respectively), much longer than that of the lithium cell. Besides, the LiFePO4 full battery (LFP||Li-Zr) enables substantially enhanced cyclability over 800 cycles at 1 C. This work paves the way for dendrite-free and long-life lithium metal batteries with well-balanced heterostructured SEI engineering.
Keywords: SEI; collaborative assembly; lithium dendrites; lithium deposition; lithium metal batteries.