Relocatable Hollow Multishelled Structure‐Based Membrane Enables Dendrite‐Free Lithium Deposition for Ultrastable Lithium Metal Batteries

Abstract Lithium metal anode holds great promise due to its highest theoretical capacity and lowest redox potential. However, its practical application is hindered by lithium dendrite growth and exhaustive side reactions, which poses concerns to both cell performance and safety. Herein, a relocatable composite membrane is developed to simultaneously inhibit dendrite growth and stabilize solid electrolyte interphase (SEI) film. The compact packing of hollow multishelled structure (HoMS) provides percolated lithium ion channels and uniform ion flux, while the combined elastic polymer endows membrane structural flexibility to dynamically accommodate volume changes, which results in dendrite‐free lithium deposition inside HoMS and underneath the membrane and stable SEI film restricted to the outer surface of HoMS. Consequently, the membrane‐modified lithium metal half cell achieves an impressive Coulombic efficiency of 99.6% for over 600 cycles. Notably, full cell paired with LiFePO 4 cathode stably runs for over 700 cycles, with a decay rate of only 0.045% per cycle, while the one paired with LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathode demonstrates a high capacity of 164.1 mAh g −1 at 1 C and a good capacity retention. This HoMS‐based composite membrane opens up new opportunities to realize the practical application of lithium metal batteries.