Janus Gel Polymer Electrolyte: Asymmetric Structure Design for Anti-CO₂ in Flexible Zinc-Air Batteries

Alkaline gel electrolytes in flexible zinc-air batteries (FZABs) suffer from CO₂ poisoning and water loss, causing decreased conductivity and carbonate crystal blockage. This work presents a Janus asymmetric PVA/PSSA‑K₂CO₃ gel polymer electrolyte (GPE) fabricated via a non-solvent induced phase separation (NIPS) method, which simultaneously provides. PVA, PSSA, and K₂CO₃ are polyvinyl alcohol, poly(4-styrenesulfonic acid), and potassium carbonate, respectively. The top dense layer (pores ∼0.28 µm) physically inhibits CO₂ diffusion and ensures H₂O retention, ensuring conductivity. The bulk spongy layer (pores ∼1.25 µm) stores OH^- and CO₃ ^2- for rapid transport. Pre‑embedded CO₃ ^2- acts as a chemical barrier, shifting the reaction CO₂ + 2OH^- ⇌ CO₃ ^2- + H₂O leftward to suppress carbonate crystallization. A FZAB using this GPE and Pt/C+RuO₂ cathode achieves 93.5 mS cm^-1 ionic conductivity, 121.3 mW cm^-2 peak power density, and prolonged cycling life in a 10 v% CO₂ atmosphere. Replacing Pt/C+RuO₂ with tri‑site FeCo_SA/NP@NGA‑600 further enhances performance due to faster cathode kinetics. This study demonstrates an effective design strategy combining Janus GPE and tri-site catalysts for high‑performance alkaline flexible ZABs.