Preparation and Performance of Integrated Cathode All-Gel Flexible Zinc-Air Batteries

Abstract

Zinc-air batteries (ZABs) attract significant attention for their suitability in addressing the expanding need for adaptable, portable devices, benefiting from their substantial energy density and affordable pricing. Conventional flexible zinc-air batteries typically employ a sandwich-style assembly. This configuration relies on simple interfacial adhesion between the electrode and electrolyte, failing to establish robust integration. Consequently, the layers experience relative slippage during mechanical stress, leading to three critical failure modes: elevated interfacial resistance, catalyst delamination, and compromised structural integrity during operation. The acceleration of the diffusion process, in conjunction with the reduction of interfacial high resistance, is instrumental in enhancing the electrochemical performance of the battery. In this study, we propose a fully hydrogel-integrated flexible zinc-air battery (ZAB), where both the electrolyte and air electrode consist of hydrogel substrates. The PVA hydrogel enhances interfacial adhesion, minimizes interfacial resistance, facilitates electron transport, and improves the battery's electrochemical performance. A PVA all-hydrogel flexible zinc-air battery containing 15% monomer has a cycling stability of 34 h and a high round-trip efficiency. This pouch hydrogel battery maintains a high-voltage output when folded to 135°, powering a wide range of microelectronic devices. It demonstrates excellent electrochemical performance under the conditions of repeated mechanical deformation. With its integrated gel electrolyte, the ZAB battery delivers efficient energy supply across diverse electronic systems. Its exceptional electrochemical stability and mechanical adaptability to bending deformations position it as a promising candidate for next-generation flexible and wearable technologies.