Molecular recognition effect enabled by novel crown ether as macrocyclic host towards highly reversible Zn anode

Abstract

Aqueous Zn2+ ion batteries present notable advantages, including high abundance, low toxicity, and intrinsic nonflammability. However, they exhibit severe irreversibility due to uncontrolled dendrite growth and corrosion reactions, which limit their practical applications. Inspired by their distinct molecular recognition characteristics, supramolecular crown ethers featuring interior cavity sizes identical to the diameter of Zn2+ ions were screened as macrocyclic hosts to optimize the Zn2+ coordination environment, facilitating the suppression of the reactivity of H2O molecules and inducing the in-situ formation of organic–inorganic hybrid dual-protective interphase. The in-situ assembled interphase confers the system with an “ion-sieving” effect to repel H2O molecules and facilitate rapid Zn2+ transport, enabling the suppression of side reactions and uniform deposition of Zn2+ ions. Consequently, we were able to achieve dendrite-free Zn2+ plating/stripping at 98.4% Coulombic efficiency for approximately 300 cycles in Zn||Cu cell, steady charge–discharge for 1360 h in Zn||Zn symmetric cell, and improved cyclability of 70% retention for 200 cycles in Zn||LMO full cell, outlining a promising strategy to challenge lithium-ion batteries in low-cost, and large-scale applications.