Regulation of Zn²⁺ Solvation Configuration in Aqueous Batteries via Selenium-Substituted Crown Ether Engineering

The efficient utilization of the metallic Zn in rechargeable aqueous Zn-ion batteries (RAZBs) struggle to suffer from parasitic Zn dendrite formation, hydrogen evolution reactions as well as severe interfacial degradation at high areal capacity loadings. This study thus proposes to employ the modified crown ether as an aqueous electrolyte additive to regulate the Zn²⁺ desolvation kinetic and facilitates the horizontally oriented (002) deposition of Zn, extending the lifespan of both the symmetric cell and full cell models. Specifically, zincophilic cyano and hydrophobic selenium atoms are incorporated into the crown ether supramolecule to enhance Zn²⁺ coordination and desolvation capability. The addition of 4-cyanobenzo-21-crown-7-selenium at a low concentration of 0.5 wt.% effectively mitigates hydrogen evolution and Zn corrosion caused by water, promoting the oriented deposition of Zn²⁺. The Zn||V₂O₅ full cell prototype, assembled with the areal capacity loadings of 2 mAh cm^-2 and N/P ratio of 2.95, exhibits negligible capacity fading at 2.0A g^-1 for 300 cycles, highlighting the commercial feasibility of supramolecular macrocycles additive for practical RAZBs applications.