High theoretical specific capacity and low electrochemical potential offered by lithium metal make it the definitive anode material for lithium batteries. Yet, unrelenting growth of dendrites forestalls the use of Li metal anode in commercial applications. To overcome this issue, we demonstrate the formation of a multi-phase composite protective layer consists of LixSi alloy, Si-linked organic oligomers and LiCl on the lithium anode surface. Due to its inherent ionic conductivity and chemical stability, the composite film can not only inhibit the formation of lithium dendrites by facilitating uniform Li-ion distribution, but also prevent unfavorable side reactions. The improved electrochemical performance is demonstrated by symmetric cells with the composite layer cycling at 1 mA cm⁻² stably for 2200 h. Protected lithium anode coupled with LiFePO₄ achieves high rate performance and better capacity retention after 400 cycles at 1C. Furthermore, cells with protected lithium anode and Li₄Ti₅O₁₂ cathode (high areal loading of 14.9 mg cm⁻²) shows 91% capacity retention after 400 cycles at 0.5 C. The effective and scalable way to stabilize lithium anode with the multi-phase composite protective layer may serve as good references for development of advanced lithium metal batteries.

锂金属提供的高理论比容量和低电化学势使其成为锂电池的确定性负极材料。然而，树枝状晶体的持续生长阻止了锂金属阳极在商业应用中的使用。为了克服这个问题，我们证明了在锂阳极表面上形成由Li x Si合金，Si连接的有机低聚物和LiCl组成的多相复合保护层的方法。由于其固有的离子导电性和化学稳定性，该复合膜不仅可以通过促进均匀的锂离子分布来抑制锂树枝状晶体的形成，而且还可以防止不利的副反应。电化学性能的提高通过复合层在1 mA cm ^-2循环的对称电池证明稳定2200小时。在1C下经过400次循环后，与LiFePO ₄结合使用的受保护锂阳极可实现高倍率性能和更好的容量保持率。此外，具有受保护的锂阳极和Li ₄ Ti ₅ O ₁₂阴极（14.9 mg cm ^-2的高面负荷）的电池在0.5 C下循环400次后显示91％的容量保持率。相复合保护层可作为高级锂金属电池开发的良好参考。