Effective stabilization of lithium metal has been hindered by the exacting requirements for the protection layer. Among all materials, the mechanical strength and electrochemical inertness of diamond is a prime candidate for lithium stabilization. Herein, we successfully rendered this desirable material compatible as lithium metal interface, which strictly satisfied the critical requirements. Our interface possessed the highest modulus among all the lithium coatings (>200 GPa), which can effectively arrest dendrite propagation. Since pinholes are the major failure mechanisms of artificial interfaces, a novel double-layer design was proposed to enhance the defect tolerance, enabling uniform ion flux and mechanical properties as confirmed by both simulation and experiments. Thanks to the multifold advantages of our interface design, high Coulombic efficiency of >99.4% was obtained at 1 mA cm⁻²; and more than 400 stable cycles were realized in prototypical lithium-sulfur cells with limited lithium, corresponding to an average anode Coulombic efficiency of >99%.

锂金属的有效稳定化已受到对保护层严格要求的阻碍。在所有材料中，金刚石的机械强度和电化学惰性是锂稳定化的主要候选材料。在此，我们成功地使这种理想的材料与锂金属界面兼容，从而严格满足了关键要求。我们的界面在所有锂涂层中具有最高的模量（> 200 GPa），可以有效地阻止枝晶传播。由于针孔是人工界面的主要失效机理，因此提出了一种新颖的双层设计来提高缺陷耐受性，从而通过仿真和实验证实了均匀的离子通量和机械性能。得益于我们界面设计的多重优势，⁻² ; 并且在锂含量有限的原型锂硫电池中实现了超过400个稳定循环，相当于平均阳极库仑效率> 99％。