Recyclable and CO2-retardant Zn–air batteries based on CO2-decorated highly conductive cellulose electrolytes

Abstract

The ever-increasing fossil fuel consumption and portable electronic device proliferation have caused numerous environmental challenges in terms of producing massive carbon dioxide (CO₂) emissions and end-of-life wastes. Incorporating naturally abundant resources into the recyclable and renewable battery components at the design stage has, therefore, become essential. Cellulose (CC) is an attractive raw material for eco-friendly solid/gel polymer electrolytes. However, they suffer from unsatisfactory ionic conductivity due to the narrow spacing between the molecular chains originating from the strong inherent inter- and intra-molecular hydrogen bonds. Herein, we propose a strategy to achieve highly conductive cellulose by bedecking the CC with CO₂via its ionization (CC-CO₂), which breaks the inherent inter- and intra-molecular hydrogen bonds. Upon being employed as quasi-solid-electrolytes for Zn–air batteries (ZABs), the CO₂-decorated CC with substantially enhanced conductivity can effectively impede the CO₂ poisoning of the electrolyte and Zn dendrite formation, endowing the fabricated ZABs with promoted electrochemical performance and stability even in a CO₂-rich atmosphere. The spent CC-CO₂ and all chemicals used for the ionization can be facilely and efficiently recycled. Moreover, the CC-CO₂ can be degraded to CO₂ and glucose on demand. The strategy here sheds light on integrating CO₂ utilization with bio-derived materials for renewable energy storage systems to meet sustainability targets.