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

Abstract

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 [ a n]daisy chain network ( DC MIN) into the ASEI to stabilize the Li metal/ASEI interface by combining the functions of energy dissipation and fast Li‐ion transport. The DC MIN featured by large‐range molecular motions is cross‐linked via efficient thiol‐ene click chemistry; thus, the DC MIN has flexibility and excellent mechanical properties. As an ASEI, the crown ether units in DC MIN 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 DC MIN. Therefore, a stable 2800 h‐symmetrical cycling (1 mA cm −2 ) and an excellent 5 C‐rate (full cell with LiFePO 4 ) performance are achieved by DC MIN‐based ASEI. Furthermore, the 1‐Ah pouch cell (LiNi 0.88 Co 0.09 Mn 0.03 O 2 cathode) with DC MIN‐coated LMA exhibits improved capacity retention (88%) relative to the Control. The molecular design of DC MIN provides new insights into the optimization of an ASEI for high‐energy LMAs.