Lithium (Li) ion batteries have witnessed a great success in areas ranging from portable electronics to electrical vehicles. Among various materials used for battery anodes, Li metal has been considered as the “Holy Grail” due to the highest theoretical capacity and lowest electrochemical potential. However, unmodified Li metal anode suffers from uncontrolled dendrite growth as well as inherent ultrahigh reactivity. Here we report a facile and universal approach to engineering Li anode by passivating anode surface through reactions with CF_x, which yields a uniform porous LiF layer on the surface of Li metal. Retaining a high theoretical specific capacity of 3680 mAh/g, a marked extension of the cycle life for Li anode after the formation of a LiF surface layer was achieved, and characterization of Li/Li₄Ti₅O₁₂ (LTO) cells with surface-engineered Li anode showed capacity retention of 94.79% after 800 cycles at 2 C, which is much higher than those in the cells with pure Li anode (62.07%). Further, enhanced stability and suppressed overpotential augment after 300 cycles were realized in symmetric cells of surface-engineered Li metal. In addition, Li/S cells with surface-engineered Li anodes also exhibit significantly improved initial columbic efficiency, cyclability, and specific capacity simultaneously. These results suggest that an engineered LiF surface layer would enable an ideal Li metal anode for high-energy-density batteries of the future.

锂离子电池在从便携式电子产品到电动汽车的各个领域都取得了巨大的成功。在用于电池阳极的各种材料中，由于最高的理论容量和最低的电化学势，锂金属被认为是“圣杯”。然而，未改性的锂金属阳极遭受不受控制的枝晶生长以及固有的超高反应性。在这里，我们报告了一种通过与CF _x反应钝化阳极表面而对锂阳极进行工程化的简便方法，该方法可在锂金属表面上形成均匀的多孔LiF层。保持3680 mAh / g的高理论比容量，在形成LiF表面层之后，Li阳极的循环寿命显着延长，并且对Li / Li进行了表征具有表面工程化锂阳极的₄ Ti ₅ O ₁₂（LTO）电池在2 C下经过800次循环后显示出94.79％的容量保持率，远高于纯锂阳极电池（62.07％）的容量保持率。此外，在表面工程化的锂金属的对称电池中，实现了300次循环后增强的稳定性和抑制的过电势增加。此外，具有表面工程化锂阳极的Li / S电池同时还具有显着改善的初始哥伦布效率，可循环性和比容量。这些结果表明，工程化的LiF表面层将为将来的高能量密度电池提供理想的Li金属阳极。