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

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.