Flexible Zinc–Air Batteries with Ampere‐Hour Capacities and Wide‐Temperature Adaptabilities

Abstract Flexible Zn–air batteries (FZABs) have significant potentials as efficient energy storage devices for wearable electronics because of their safeties and high energy‐to‐cost ratios. However, their application is limited by their short cycle lives, low discharge capacities per cycle, and high charge/discharge polarizations. Accordingly, herein, a poly(sodium acrylate)–polyvinyl alcohol (PANa–PVA)–ionic liquid (IL) hydrogel (PANa–PVA–IL) is prepared using a hygroscopic IL, 1‐ethyl‐3‐methylimidazolium chloride, as an additive for twin‐chain PANa–PVA. PANa–PVA–IL exhibits a high conductivity of 306.9 mS cm −1 and a water uptake of 2515 wt% at room temperature. Moreover, a low‐cost bifunctional catalyst, namely, Co 9 S 8 nanoparticles anchored on N‐ and S‐co‐doped activated carbon black pearls 2000 (Co 9 S 8 ‐NSABP), is synthesized, which demonstrates a low O 2 reversibility potential gap of 0.629 V. FZABs based on PANa–PVA–IL and Co 9 S 8 ‐NSABP demonstrate high discharge capacities of 1.67 mAh cm −2 per cycle and long cycle lives of 330 h. Large‐scale flexible rechargeable Zn–air pouch cells exhibit total capacities of 1.03 Ah and energy densities of 246 Wh kg cell −1 . This study provides new information about hydrogels with high ionic conductivities and water uptakes and should facilitate the application of FZABs in wearable electronics.