High-performance solid-state electrolytes with healability to repair mechanical damages are important for the fabrication of Li-ion batteries (LIBs) with enhanced safety and prolonged service life. In this study, we present the fabrication of healable, highly conductive, flexible, and nonflammable ionogel electrolytes for use in LIBs by loading ionic liquids and Li salts within a hydrogen-bonded supramolecular poly(ionic liquid) copolymer network. The ionogel electrolytes exhibit ionic conductivities as high as 10 −3 S/cm, which is comparable to the conventional liquid electrolytes. The Li/LiFePO 4 battery assembled with the ionogel membrane exhibits excellent cycling performance and delivers a steady high discharge capacity of 147.5 mA h g −1 and Coulombic efficiency of 99.7% after 120 cycles at the charge/discharge rate of 0.2 C. Importantly, the ionogel membranes can heal damages outside or inside a battery because of the reversible nature of the supramolecular interactions between the components. The damaged ionogel membranes after being healed can effectively restore the original performance of the LIBs.

Fabrication of self-healing/healable materials using reversible interactions that are governed by their inherent chemical features is highly desirable because it avoids the introduction of extra groups that may present negative effects on their functions. The present study exploits the inherently featured electrostatic interactions of the ion pairs in polymeric ionic liquids (PILs) as the driving force to fabricate healable PIL copolymers. The healable PIL copolymers are fabricated through the copolymerization of the IL monomers with ethyl acrylate followed by the replacement of Br counteranions with bulkier ones such as bis(trifluoromethanesulfonyl)imide (TFSI). Without modifying the chemical structures of the PIL moieties, the healing performance of the as-prepared PIL copolymers can be effectively mediated by their counteranions. The PIL copolymers that do not possess healability when paired with Br counteranions become healable after exchanging the Br counteranions with larger-sized ones (e.g., TFSI). The PIL copolymers paired with bulky counteranions exhibit enhanced chain mobility and highly reversible ion-pair interactions, which facilitate the healing process. The PIL copolymers paired with TFSI anions can completely heal the damage/cut upon heating at 55 °C for 7.5 h. Meanwhile, the counteranions with larger sizes not only benefit the healing performance of the PIL copolymers but also enhance their ion conductivity. The ion conductivity of the PIL copolymers paired with TFSI is an order of magnitude higher than that of the PIL copolymers paired with Br. Therefore, the as-prepared healable PIL copolymers are potentially useful as solid electrolytes in PIL-based energy devices to improve their safety and reliability.

A new ionogel electrolyte with an organic–inorganic semi-interpenetrating network not only suppresses Li dendrite formation and Al current collector corrosion, but also improves Li+ transport capability and stability.

The development of high‐performance solid‐state electrolytes to replace conventional liquid organic electrolytes has received intensive attention because of the improvements in the safety, flexibility, reliability, and cycling stability of lithium‐ion batteries (LIBs). In this work, we present a double‐network ionogel electrolyte (DNIE) through the preparation of interpenetrating polymer networks (IPNs). This DNIE exhibits good mechanical properties, excellent flexibility, nonflammability, high ionic conductivity (4.13×10−4 S cm−1 at room temperature), electrochemical stability (>4.8 V), and the ability to suppress Li dendrite formation. The Li/LiFePO4 cell assembled with the DNIE exhibits superior cycling performance while also delivering a steady high discharge capacity of 133.7 mAh g−1 and a Coulombic efficiency of 99.8 % after 220 cycles at a charge/discharge rate of 0.2 C. Importantly, the DNIE(200 %)‐20 % electrolytes can be prepared on the surface of graphite anodes through in situ gelling, which can improve the stability of the active layer and the adhesion between the active layer and current collector in mechanical bending at different angles. After assembling into soft‐packed batteries in the configuration of LiCoO2|DNIE(200 %)‐20 %|graphite via the in situ gelling of DNIE(200 %)‐20 % on the surface of the graphite electrode, the flexible batteries showed excellent cycling stability (capacity retention >98 %) even when folded more than 100 times.

The Cover Feature shows a double‐network ionogel electrolyte (DNIE) through the preparation of interpenetrating polymer networks. This DNIE exhibits good mechanical properties, excellent flexibility, nonflammability, high ionic conductivity, electrochemical stability (>4.8 V), and the ability to suppress Li dendrite formation. More information can be found in the Research Article by Z. Li et al.