Breaking the lithium deposition limit: in situ fabrication of CoN-doped carbon skeleton membrane for anode-free lithium metal batteries

Abstract

Anode-free lithium metal batteries (AFLMBs) leverage a bare current collector (CC) as a lithium deposition substrate to achieve high energy density and reduced manufacturing costs. However, severe nucleation overpotential and dendritic growth, rooted in the Cu–Li lattice mismatch, hinder their practical deployment. Herein, a dense zeolitic imidazolate framework-67 (ZIF-67) polycrystalline membrane is epitaxially grown in situ on Cu CC via liquid-phase epitaxy and subsequently converted into a CoN-doped carbon skeleton membrane (67MC@Cu) through thermal treatment. The embedded CoN nanoparticles, evolved from {CoN₄} units in ZIF-67, serve as highly lithiophilic sites that dynamically regulate lithium nucleation and suppress dendrite formation. The binder-free fabrication maximizes the exposure of active sites while preserving the functionality of the MOF-derived architecture. As a result, full cells assembled with 67MC@Cu exhibit markedly enhanced cycling stability, retaining 92.0% capacity after 280 cycles—far surpassing 20.2% retention of commercial carbon-coated Cu (C@Cu). This work provides an effective interfacial engineering strategy to advance the practical implementation of AFLMBs.