Mechanically Interlocked Interphase with Energy Dissipation and Fast Li‐Ion Transport for High‐Capacity Lithium Metal Batteries

Abstract Constructing an artificial solid electrolyte interphase (ASEI) on Li metal anodes (LMAs) is a potential strategy for addressing the dendrite issues. However, the mechanical fatigue of the ASEI caused by stress accumulation under the repeated deformation from the Li plating/stripping is not taken seriously. Herein, this work introduces a mechanically interlocked [an]daisy chain network (^DCMIN) into the ASEI to stabilize the Li metal/ASEI interface by combining the functions of energy dissipation and fast Li‐ion transport. The ^DCMIN featured by large‐range molecular motions is cross‐linked via efficient thiol‐ene click chemistry; thus, the ^DCMIN has flexibility and excellent mechanical properties. As an ASEI, the crown ether units in ^DCMIN not only interact with the dialkylammonium of a flexible chain, forming the energy dissipation behavior but also coordinate with Li ion to support the fast Li‐ion transport in ^DCMIN. Therefore, a stable 2800 h‐symmetrical cycling (1 mA cm⁻²) and an excellent 5 C‐rate (full cell with LiFePO₄) performance are achieved by ^DCMIN‐based ASEI. Furthermore, the 1‐Ah pouch cell (LiNi_0.88Co_0.09Mn_0.03O₂ cathode) with ^DCMIN‐coated LMA exhibits improved capacity retention (88%) relative to the Control. The molecular design of ^DCMIN provides new insights into the optimization of an ASEI for high‐energy LMAs.