A highly stable zinc–air battery based on a non-alkaline agar gel electrolyte

Abstract

Zinc–air batteries are considered promising candidates for the next generation of batteries due to their significant advantages in theoretical specific capacity, safety, and environmental friendliness. The combination of gel polymer electrolytes and zinc–air batteries further expands future energy storage applications. However, traditional alkaline gel zinc–air batteries are usually constructed by post-stacking methods, and their poor interfacial contact and weakened long-term durability in the ambient air hinders practical applications. Here, we synthesized a non-alkaline gel electrolyte with a liquid–solid phase transition mechanism utilizing agar, and constructed an integrated gel zinc–air battery by direct injection and encapsulation methods. This strategy realizes the integrated assembly of non-alkaline gel zinc–air full batteries, thereby obtaining all-round high stability. The agar gel electrolyte endows the battery with outstanding performance, including a high output specific capacity (706 mAh g Zn⁻¹), a long discharge duration (270 h at 0.1 mA cm⁻²), and a significant operational life (850 h at 0.2 mA cm⁻²). Importantly, the integrated zinc–air pouch battery can achieve a high zinc utilization rate of over 80% in various discharge states and exhibit satisfactory cycling stability (>200 h at 0.1 mA cm⁻²). This technology alleviates the current challenges of gel zinc batteries, and highlights the direction for the development of non-alkaline gel zinc–air full batteries.