Safe, Flexible, and High-Performing Gel-Polymer Electrolyte for Rechargeable Lithium Metal Batteries
Julen Castillo, Alexander Santiago, Xabier Júdez, Íñigo Garbayo, José Antonio Coca Clemente, Maria C. Morant‐Miñana, Aitor Villaverde, José A. González‐Marcos, Heng Zhang, Michel Armand, Chunmei Li
Abstract
The use of gel polymer electrolytes (GPEs) is of great interest to build high-performing rechargeable lithium metal batteries (LMBs) owing to the combination of good electrochemical properties and improved safety. Herein, we report a facile and scalable one-pot preparation method of a GPE based on highly safe polyethylene glycol dimethyl ether (PEGDME) plasticizer in a poly(vinylidenefluoride-co-hexafluoropropylene) (PVDF-HFP) polymer matrix. The prepared GPE exhibits excellent safety (nonflammability and thermal stability up to 250 °C) and outstanding electrochemical properties at room temperature (high ionic conductivity of 3.4 × 10–4 S cm–1 and high lithium transference number). Moreover, high loading LiFePO4 (6–7 mg cm–2) LMB using such GPE delivers a good C-rate response and high capacity (ca. 1 mAh cm–2 at C/10) with an excellent retention of 98% after 60 cycles in coin cell configuration. Notably, the prototype pouch cell (ca. 19 mAh at C/10) provides remarkable safety, mechanical flexibility, and strong tolerance toward bending and cutting. These results suggest that the prepared GPE is a promising candidate for the development of high performance, flexible, and safe LMBs that operate at room temperature, as well as for other energy storage systems beyond lithium-ion technologies.