Agar-PVA/GO double network gel electrolyte for high performance flexible zinc-air batteries

Flexible zinc-air batteries (FZABs) have attracted a lot of attention because of their high energy density, low cost, and good safety. As the ‘blood’ of FZABs, electrolytes are one of the research focuses. In this paper, we report a double network hydrogel as FZABs electrolyte. The hydrogel is cross-linked by stiff agar as the first network and tough polyvinyl alcohol microcrystals and polymer chains as the second network. The maximum extension at maximum tensile strength (388 Kpa) of the prepared double network gel is close to 246%. The gel is suitable for alkaline and neutral electrolytes in FZABs. The alkaline gel electrolyte has high ionic conductivity (75 mS/cm) and the assembled alkaline FZAB has a high power density of 123.7 mW/cm2. While the better water retention of neutral gel electrolyte makes it more stable, the assembled neutral FZAB has a long discharge time and favorable cycle life of more than 60 h at a current density of 0.5 mA/cm2. In addition, FZABs can not only change shape and size but also operate under different bending conditions without reducing the electrochemical performance, indicating that high-performance FZABs assembled by this electrolyte with efficient, safe, and flexible, and have great potential for applications.