Sulfonated lignin-based polymer electrolyte enables dendrite-free Zn anode for flexible Zn-air batteries.

Flexible zinc-air batteries (FZABs) are regarded as a promising energy source for wearable and portable electronic applications, owing to their environmental friendliness, inherent safety and the utilization of ambient oxygen as the cathode material in the current decade. However, the practical and large-scale deployment of FZABs is hindered by the presence of several bottleneck factors, including sluggish ion transport kinetics, poor alkali resistance, and inferior mechanical properties. The gel electrolyte represents a crucial component in FZAB and needs to be optimised to match the zinc anode to meet these challenges. Recently, gel electrolytes based on natural polymer-based have shown great potential in tackling these issues of FZABs. In this work, we designed a sulfonate-functionalized gel polymer electrolyte (GPE) for FZABs with enhanced alkali tolerance, high ionic conductivity, and improved zinc anode stability compared to conventional PVA gel electrolytes. Benefiting from these advantages, the fabricated FZAB delivers a high power density of 88.15 mW cm, and exceptional cyclic durability of 250 h. The assembled zinc-air batteries are capable of supplying dependable power to electronic clocks. This study contributes to the advancement of the design of natural high-performance polymer-based electrolyte materials and offers the prospect for next-generation wearable electronics.