High Fire-Safety Ultrathin Porous Lithium Anode with Bulk Ion-Conductive Network

Lithium metal anodes promise high-energy-density batteries ^1,2 but are limited by intrinsically low bulk ionic conductivity, which promotes preferential surface Li ⁺ plating/stripping during cycling ^3,4 , leading to dendrite growth and serious safety risks ^5,6 . Although strategies using internal ion-conductive networks and lithium reservoirs show promise ⁷ , creating uniform pores in lithium metal remains challenging due to its poor mechanical strength, low melting point, and high chemical reactivity ⁸ . Here we report a scalable method integrating a hydrogenated fluoropolymer into lithium via roll-bonding, followed by low-temperature annealing. This triggers in-situ Li-H bond formation and decomposition to produce uniform pores decorated with co-generated ion-conducting species, while lithiation of the fluoropolymer generates a robust LiF-rich framework. The resulting ultrathin porous lithium anodes exhibit a bulk ionic conductivity ~ 66% higher than that of pure metallic lithium, allowing stable cycling at 5 mA cm ^− 2 for over 2000 hours in commercial electrolytes, wherein Li ⁺ deposition and stripping occur within its internal pores. Additionally, it demonstrates self-extinguishing performance upon ignition in air. This roll-to-roll-compatible strategy provides a practical pathway to safe, high-performance lithium-metal batteries and extends to other porous alkali metals.