The Design of Interfacial Organic-Riched Phase by Molecular Interlocking for Stable Zn Anodes

Rechargeable aqueous zinc-ion batteries (ZIBs) are promising energy storage devices due to their high safety and environmental friendliness. However, they suffer from some issues in Zn anodes, including dendrites, hydrogen evolution reaction, and byproducts. Herein, an organic-riched phase (ORP) layer was constructed on Zn anode by introducing sodium anthraquinone-1-sulfonate (AQS) into the aqueous electrolyte with ethylene glycol (EG). In such an electrolyte, the zincophilic -SO₃ ^- groups of AQS molecules preferentially adsorb on Zn anodes, and stable chemical bonds are achieved between them. After that, the low-polarity and hydrophobic anthraquinone group in the AQS layer tends to repel H₂O molecules. Simultaneously, more AQS and EG molecules are attracted and migrate toward AQS layer due to polar compatibility, constructing the AQS/EG-riched layer on the Zn anode by the interlocking effect among them. When Zn²⁺ solvated structures migrate through the ORP layer on Zn anode surface, AQS and EG molecules enter Zn²⁺ solvated structures, and thus, the solvated H₂O molecules are removed. As a result, hydrogen evolution and side reactions were significantly suppressed, and the Coulombic efficiency of Zn anodes during plating/stripping process reached 99.56%. To illustrate the feasibility of the ORP layer, Zn||V₂O₅ full cells were assembled and exhibited superior cycling performance.