Super‐Stretchable Zinc–Air Batteries Based on an Alkaline‐Tolerant Dual‐Network Hydrogel Electrolyte

TLDR

Stretchable devices require elastic hydrogel electrolytes, but most hydrogels lose stretchability in strong alkaline solutions, which has prevented the development of highly stretchable zinc‑air batteries. The study develops the first super‑stretchable flat (800 %) and fiber‑shaped (500 %) zinc‑air batteries using an alkaline‑tolerant dual‑network hydrogel electrolyte, aiming to enable zinc‑air batteries for flexible electronics, smart clothes, and other alkaline‑based energy devices. The dual‑network hydrogel electrolyte combines sodium polyacrylate chains forming soft domains with carboxyl groups neutralized by hydroxyls and cellulose as a potassium hydroxide stabilizer, yielding high alkaline tolerance. The batteries deliver 108.6 mW cm⁻² (210.5 mW cm⁻² at 800 % stretch) and retain stable power under heavy deformation, with 500 % fiber‑shaped versions showing comparable performance, and the authors also demonstrate a bendable battery‑display system and a waterproof weavable fiber zinc‑air battery.

Abstract

Abstract Stretchable devices need elastic hydrogel electrolyte as an essential component, while most hydrogels will lose their stretchability after being incorporated with strong alkaline solution. This is why highly stretchable zinc–air batteries have never been reported so far. Herein, super‐stretchable, flat‐ (800% stretchable) and fiber‐shaped (500% stretchable) zinc–air batteries are first developed by designing an alkaline‐tolerant dual‐network hydrogel electrolyte. In the dual‐network hydrogel electrolyte, sodium polyacrylate (PANa) chains contribute to the formation of soft domains and the carboxyl groups neutralized by hydroxyls as well as cellulose as potassium hydroxide stabilizer are responsible for vastly enhanced alkaline tolerance. The obtained super‐stretchable, flat zinc–air battery exhibits a high power density of 108.6 mW⋅cm −2 , increasing to 210.5 mW⋅cm −2 upon being 800% stretched. Similar phenomena are observed for the 500% stretchable fiber‐shaped batteries. The devices can maintain stable power output even after being heavily deformed benefiting from the highly soft, alkaline‐tolerant hydrogel electrolyte developed. A bendable battery‐display system and water proof weavable fiber zinc–air battery are also demonstrated. This work will facilitate the progress of using zinc–air battery powering flexible electronics and smart clothes. Moreover, the developed alkaline‐tolerant super‐stretchable electrolyte can also be applied for many other alkaline electrolyte‐based energy storage/conversion devices.