Safe, Flexible, and High-Performing Gel-Polymer Electrolyte for Rechargeable Lithium Metal Batteries

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 degrees C) and outstanding electrochemical properties at room temperature (high ionic conductivity of 3.4 x 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.

Automated summary

The study demonstrates a facile and scalable method to prepare gel polymer electrolytes (GPEs) using highly safe PEGDME plasticizer in a PVDF-HFP polymer matrix, resulting in excellent safety and electrochemical properties at room temperature. The GPE exhibits high ionic conductivity and lithium transference number, making it a promising candidate for the development of high performance, flexible, and safe LMBs.