Performance Regulation of Sulfonated Poly(ether ether ketone) for Preparing Multi-Adaptive Electrolyte and Battery Separator of Wide-Temperature Flexible Zn-Air Batteries.

Abstract

Herein, sulfonated poly(ether ether ketone) (SPEEK) is employed to fabricate both the separator and gel electrolyte for solid zinc-air batteries (ZABs), leveraging its rigid backbone and abundant sulfonic acid groups in side chains of SPEEK. Incorporating glycerol into the separator (making SPEEKG-Zn²⁺) enhances its low-temperature performance. In the SPEEKG-Zn²⁺ separator, the sulfonic acid groups of SPEEKG-Zn²⁺ facilitate uniform deposition of Zn²⁺ on Zn anode and suppress OH^- transfer through interacting with Zn²⁺. This dual functionality effectively minimizes dendrite growth and chemical corrosion, as confirmed by experiments and theoretical calculation. Additionally, the gel electrolyte is prepared with SPEEK membrane and crosslinked chitosan-glycerol gel. The electrolyte exhibits excellent mechanical properties, thermal stability and high ionic conductivity (51.04 ± 0.3 mS cm^-1). ZABs with the electrolyte and SPEEKG-Zn²⁺ separator shows stable cyclic performance up to 56 h at 40 °C, high power density of 171.6 mW cm^-1, specific capacity of 896.1 mAh g^-1 at 60 °C, and wide temperature adaptability in -40 to 60 °C, which are superior to those of the recently reported ZABs. These properties are highly desirable for flexible ZABs functioning effectively under extreme temperature conditions.