Synergistically Modified CNF/PAM Hydrogel with LiCl and Carboxylated Graphene for Zinc–Air Batteries

Flexible zinc–air batteries (ZABs) with high theoretical energy density, intrinsic safety, and low cost have gained significant attention for flexible energy storage devices. However, conventional single-component electrolytes struggle to simultaneously meet comprehensive performance requirements, including mechanical strength, conductivity, practical specific capacity, and cycling stability. Herein, carboxylated graphene (CG) and lithium chloride (LiCl) were incorporated into a cellulose nanofibril/polyacrylamide (CNF/PAM) hydrogel matrix to fabricate a series of multi-component, dual-crosslinked high-performance composite hydrogel electrolytes toward flexible and rechargeable zinc–air batteries. The results reveal that the LiCl-CG@CNF/PAM composite hydrogel achieves an ionic conductivity of up to 4.473 mS·cm−1 and exhibits excellent mechanical properties, with a tensile elongation of 457% at a stress of 151.5 kPa. The assembled flexible ZABs deliver a peak power density of 60.7 mW·cm−2, a steady discharge duration of 38 h, and a long cycling lifetime of 47 h. This hydrogel electrolyte affords a novel strategy for the design and fabrication of high-performance, long-lifetime flexible wearable zinc–air batteries.