Multifunctional Zwitterionic Self‐Healing Polymer Electrolytes for Anode‐Free Lithium‐Metal Batteries: a Computational Perspective

The practical application of anode-free lithium-metal batteries (AFLMBs) is limited by their poor cycling performance and unstable solid electrolyte interphase (SEI). Self-healing solid polymer electrolytes (SHSPEs) offer excellent flexibility and healing capabilities, which are expected to mitigate dendrite growth and improve AFLMB cycling performance. In this study, a novel zwitterionic SHSPE, P(SBMA-co-BA):LiTFSI, is proposed, and its suitability for AFLMBs is evaluated through density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. The sulfonate (RSO₃ ^-) group promotes Li⁺ ion transport, and the electrostatic interaction between RSO₃ ^- and NR₄ ⁺ groups drives the electrolyte's self-healing after material damage. Electrolyte degradation on the Cu current collector during Li-nucleation and on the Li metal surface during extensive Li metal plating is further examined. The SEI components are identified using atomic charge distribution analysis, which is typically compared with X-ray photoelectron spectroscopy (XPS) data. The resulting organic/inorganic hybrid SEI demonstrates excellent flexibility and stability, and the long-chain sulfonate-containing compound facilitates rapid Li-ion conduction and uniform Li metal plating. The multifunctional zwitterionic SHSPE, P(SBMA-co-BA):LiTFSI, thus shows significant potential to enhance the cycling performance of AFLMBs, paving the way for their practical application.