Molten-Li infusion of ultra-thin interfacial modification layer towards the highly-reversible, energy-dense metallic batteries

The practical issues of uncontrollable dendrite growth, infinite volume propagation and dynamic interfacial properties hinder the deployment of the metallic anodes in the realistic energy-dense batteries. In this study, an ultra-thin (6.3 µm), lightweight (0.35 mg cm^-2), dual-functionalized composite layer that derived from the ZIF-67@ZIF-8 core-shell structure effectively modifies the Cu foil substrate (denoted as the Co@Zn-CNT-Cu). The interfacial engineering deliberately involves the atomically distributed Zn species riveted on the exterior surface of the carbonaceous units; meanwhile the in-situ grown carbon nanotubes (CNTs) threaded from the interior Co-centers reinforce the structural integrity of the dodecahedron storage units. As the Co@Zn-CNT-Cu substrate with the precise control over the molten-Li infusion (0.5×excess) integrates with the LiNi_0.8Mn_0.1Co_0.1O₂ (NMC-811) cathode (10.80 mg cm^-2) in a single-layer pouch cell, the prototype exhibits the enhanced cycling reversibility and Li utilization degree with operando phase tracking via transmission-mode X-ray diffraction. The interfacial engineering of the substrate with the controlled molten-Li infusion thus presents a promising strategy to harness the energy-dense merits of metallic batteries.