Electrophoretic Interfacial Engineering Enables Self-Healing Ionomer Interphase for Anode-Free Lithium Metal Batteries

Anode-free lithium metal batteries (AFLMBs) are considered promising candidates for next-generation high-energy-density batteries. However, AFLMBs suffer from the continuous depletion of active lithium stemming from an unstable solid electrolyte interphase (SEI), as well as the structural instability of the anode caused by severe volume changes during charge−discharge cycles. Herein, a self-healing ionomer interphase [P(AG-D-C + )@Cu(ED)] is fabricated on a copper current collector via electrophoretic deposition of a cationic copolymer [P(AG-D-C + )]. Owing to the incorporation of functional monomers such as 3-methacrylamido dopamine (DMA) and poly(ethylene glycol) methyl ether methacrylate ( m PEG), the interphase of the P(AG-D-C + ) ionomer demonstrates outstanding self-healing capability, strong adhesion, and high Li + transport efficiency. As a result, the as-assembled Li||P(AG-D-C + )@Cu(ED) half-cell delivers excellent cycling stability, maintaining a Coulombic efficiency (CE) of 99.2% over 200 cycles. This work provides a novel strategy for high-performance AFLMBs.