The cost-effective mass production of high-performance ultrathin lithium metal anodes is a bottleneck hindering the commercialization of high-energy-density Li metal batteries. Compared to complex and expensive conventional fabrication techniques including sputtering, electrodeposition, and pressure-rolling, the wet coating of molten Li on a Cu sheet is a very promising strategy. Unfortunately, the wettability of molten Li on the Cu surface is very poor, creating difficulty in achieving a uniform Li film. Herein, a facile and efficient approach to the application of melt coatings is realized through the alloying reaction between molten Li and the heated Cu surface. An ultrathin and uniform Li film with a thickness of 5 − 50 µm is prepared via roll-to-roll fabrication. Remarkably, a three-dimensional LiCu_x solid-solution alloy skeleton is formed inside the ultrathin Li, achieving the dual purpose of lithiophilicity and high performance. The full cell with the N/P ratio of 3.2, consisting of a LiFePO₄ cathode with an areal capacity of 1.58 mAh·cm⁻² and a 25 µm thick LiCu_x/Li composite anode, exhibited stable cycling for more than 480 cycles at 1 C. This work provides a potential solution for the industrial production of high-performance and cost-effective ultrathin Li metal anodes.

高性能超薄锂金属负极的低成本大规模生产是阻碍高能量密度锂金属电池商业化的瓶颈。与复杂且昂贵的传统制造技术（包括溅射、电沉积和压延）相比，在铜片上湿法涂覆熔融锂是一种非常有前途的策略。不幸的是，熔融锂在铜表面的润湿性非常差，难以获得均匀的锂薄膜。在此，通过熔融锂和加热的铜表面之间的合金化反应，实现了一种简便有效的熔融涂层应用方法。通过卷对卷制造制备了厚度为 5-50 µm 的超薄且均匀的锂薄膜。值得注意的是，超薄Li内部形成了三维LiCu _x固溶体合金骨架，实现了亲锂性和高性能的双重目的。由面积容量为1.58 mAh·cm ^-2的LiFePO ₄正极和25μm厚的LiCu _x /Li复合负极组成的N/P比为3.2的全电池，在480个循环以上表现出稳定的循环。 1 C。这项工作为高性能且经济高效的超薄锂金属负极的工业生产提供了潜在的解决方案。