CO₂ Ionized Poly(vinyl alcohol) Electrolyte for CO₂‐Tolerant Zn‐Air Batteries

Abstract CO₂ poisoning of alkaline electrolytes is a critical issue that affects the energy efficiency and lifespan of Zn‐air batteries. However, few strategies have been explored to address this issue because it is challenging to block CO₂ from the outer atmosphere. Herein, a CO₂‐tolerant flexible quasi‐solid‐state electrolyte for Zn‐air batteries, which is achieved by the pre‐fixation of CO₂ on poly(vinyl alcohol) (PVA) via its ionization in the form of side ‐OCO₂^‐ groups (PVA‐TMG), is reported. The pre‐fixation of CO₂ enables excellent CO₂ tolerance and alleviates the Zn dendrite and ZnO deposition, because the ‐OCO₂^‐ groups can strongly interact with the Zn²⁺. In addition, PVA‐TMG exhibits higher ionic conductivity and better water retention capability than the pristine PVA. Consequently, the fabricated Zn‐air batteries deliver excellent performance in both air and a CO₂‐rich atmosphere. The optimized PVA‐TMG presents a cycling lifetime 12 times longer than that of the pristine PVA in the atmosphere with 22.7 vol% CO₂. The feasible study presented here presents a new milestone in CO₂ utilization with energy storage technology.