Investigating the role of non-ionic surfactants as electrolyte additives for improved zinc anode performance in...

Zinc metal anodes encounter significant challenges, including dendrite growth, hydrogen evolution, and corrosion, all of which impede the rate capability and longevity of aqueous zinc-ion batteries (AZIBs). To effectively tackle these issues, we introduced Tween-80 into the traditional ZnSO₄ electrolyte as an additive. Tween-80 possesses electronegative oxygen atoms that enable it to adsorb onto the zinc (Zn) anode surface, facilitating the directional deposition of Zn metal along the (002) orientation. The hydroxyl and ether groups within Tween-80 can displace some of the coordinated water molecules in the Zn²⁺ inner solvation shell. This disruption of the hydrogen bond network regulates the solvation structure of Zn²⁺ ions and suppresses the possibility of hydrogen evolution. Moreover, the long hydrocarbon chain present in Tween-80 exhibits excellent hydrophobic properties, aiding in the resistance against corrosion of the Zn anode by water molecules and reducing hydrogen evolution. Consequently, a symmetric cell equipped with the Tween-80 additive can cycle stably for over 4000 h at 1 mA cm^-2 and 1 mA h cm^-2. When paired with the V₂O₅ cathode, the full cell demonstrates a high-capacity retention rate exceeding 80 % over 1000 cycles at a current density of 2 A g^-1. This study underscores the advantages of utilizing non-ionic surfactants for achieving high-performance aqueous zinc-ion batteries.