Tetramethylguanidine-Modified Graphene Oxide as a Gel Polymer Electrolyte Additive for Improving the Performance of Flexible Zinc-Air Batteries

Abstract

Flexible zinc-air batteries (FZABs) present a promising solution for the next generation of power sources in wearable electronics, owing to their high energy density, cost-effectiveness, and safety. However, solid-state electrolytes for FZABs continue to face challenges related to rapid water loss and low ionic conductivity. In this study, a hydrophilic and stable tetramethylguanidine-modified graphene oxide as an additive, which is incorporated into sodium polyacrylate to develop a high-performance gel polymer electrolyte (GPE), is designed. The addition of additives makes GPE more hydrophilic, allowing for a wider hydrogen bonding network and more efficient ion transport channels. Due to its stable structure, abundant water channels and fast OH⁻ conductivity, GPE also offers excellent mechanical properties, long-lasting water retention, and high ionic conductivity (173.9 mS cm⁻¹). FZABs assembled with this GPE exhibit a high open-circuit voltage of 1.558 V, a cycle life of 230 h, a specific capacity of 810.3 mAh g⁻¹, and a peak power density of 130.5 mW cm⁻², coupled with impressive flexibility. These characteristics underscore their significant potential for applications in wearable electronics.