Lithium metal has been deemed as the most attractive anode due to its high theoretical capacity and low anode potential. Unfortunately, its development still faces various challenges, including dendritic Li growth and low Coulombic efficiency. Here, we demonstrate that a light-weight, flexible, and free-standing 3D hollow carbon fiber (3D-HCF) container with high electroactive surface area can significantly reduce local current density and improve the Li deposition behavior. Li is confined within the interspace among the fibers and inside the hollow tubular fibers without uncontrollable Li dendrites. The Li anode in the 3D-HCFs exhibits high Coulombic efficiency (∼99.5% over 350 cycles), large areal capacity, and long-running lifespan (>1,200 hr) with an exceptionally low overpotential (<20 mV). A full cell with a LiFePO₄ cathode shows flat voltage profiles and good cycle life. We expect this work to inspire other Li container designs to promote the development of Li metal anodes.

锂金属由于其高理论容量和低阳极电位而被认为是最具吸引力的阳极。不幸的是，其发展仍然面临各种挑战，包括树枝状锂的生长和低库仑效率。在这里，我们证明了具有高电活性表面积的轻质，柔性和独立式3D中空碳纤维（3D-HCF）容器可以显着降低局部电流密度并改善Li沉积行为。Li被限制在纤维之间的间隙内和中空管状纤维的内部，而没有不可控制的Li树枝状晶体。3D-HCF中的Li阳极具有很高的库仑效率（在350个循环中约为99.5％），较大的面容量和较长的使用寿命（> 1,200小时）以及极低的过电势（<20 mV）。阴极显示出平坦的电压曲线和良好的循环寿命。我们希望这项工作能激发其他锂容器的设计，以促进锂金属阳极的发展。