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 FeCoSA/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.