A Skin‐Mimicked Polymer Gel Electrolyte for Stabilizing Lithium Metal Batteries

Abstract The electrolytes for advanced lithium‐metal batteries need to simultaneously achieve high‐performances in ion‐conductivity, lithium‐ion transference number, elasticity and mechanical strength, and safety etc. Gel polymer electrolytes (GPEs) are promising, however, conventional GPEs find it challenging to achieve all these performances, mainly due to a poor control of the liquid plasticizer inside. Here, inspired by the animal skins that can perfectly overcome the trade‐off between the mechanics and complex biofunctions via water‐encapsulation inside cellular network, it is attempted to design and fabricate a type of skin‐inspired nonflammable elastic GPE (SINE‐GPE) to address this challenge. To do that, an anti‐solvent induced self‐assembly (ASISA) strategy is proposed to fabricate a porous vesicular membrane based on a triblock thermoplastic polyurethane (i.e., the SINE‐skeleton). Then, nonflammable liquid electrolyte is encapsuled inside the SINE‐skeleton to prepare the SINE‐GPE. The resultant SINE‐GPE achieves not only a high gel‐strength of 2.0 ± 0.1 MPa, a recoverable strain of 90% and a high ionic conductivity of 1.2 × 10 −3 S cm −1 at RT, but also selective lithium‐ion transport (t Li+ = 0.82). Consequently, this SINE‐GPE can effectively stabilize lithium‐metal anode with a smooth solid‐electrolyte‐interphase, which is explained by a self‐massaging mechanism of the SINE‐GPE during lithium stripping and deposition.