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

Abstract

Abstract CO 2 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 CO 2 from the outer atmosphere. Herein, a CO 2 ‐tolerant flexible quasi‐solid‐state electrolyte for Zn‐air batteries, which is achieved by the pre‐fixation of CO 2 on poly(vinyl alcohol) (PVA) via its ionization in the form of side ‐OCO 2 ‐ groups (PVA‐TMG), is reported. The pre‐fixation of CO 2 enables excellent CO 2 tolerance and alleviates the Zn dendrite and ZnO deposition, because the ‐OCO 2 ‐ groups can strongly interact with the Zn 2+ . 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 CO 2 ‐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% CO 2 . The feasible study presented here presents a new milestone in CO 2 utilization with energy storage technology.