Simultaneous Inhibitions of Volume Variation and Water Decomposition via Interwoven Structure of Hydrophilic/Hydrophobic Fibers for Stable Zn Electrode

Heterogeneous volume expansion and water decomposition-induced zinc (Zn) corrosion are two of the main challenges hindering stable Zn electrodes in rechargeable aqueous Zn batteries (AZBs). Herein, an interwoven structure of hydrophilic/hydrophobic fibers is proposed to address the complex issue of Zn electrode, via a self-assembly process of hydrophobic polyethylene terephthalate (PET) fibers and hydrophilic carboxylated carbon nanotubes (CNTs). It is revealed that O-containing groups on the carboxylated CNT clusters can improve the Zn²⁺ desolvation and transfer kinetics, thereby suppressing co-decomposition of water molecules that are further excluded from the structure by the hydrophobic PET fibers, significantly suppressing hydrogen evolution reactions and Zn corrosions. Meanwhile, favorable formation of high-work-function Zn-O sites on the O-containing groups of carboxylated CNTs further engenders an electron-withdrawing effect to enable in-depth and confined Zn deposition, leading to a low volume variation of 13.8% for a practical Zn deposition capacity of 4 mAh cm^-2. Based on the simultaneous inhibitions of volume variation and water decomposition, high coulombic efficiency beyond 99.3% is realized for Zn plating/stripping at elevated current density up to 3 mA cm^-2, demonstrating the reliability of the interwoven structure of hydrophilic/hydrophobic fibers for stable Zn electrode in AZBs.