Promoting Zn2+ migration through polar perovskite dielectric layer on Zn metal anode for the enhanced aqueous Zn-ion batteries

Abstract

Aqueous zinc-ion batteries (AZIBs) have gained significant attention as promising next-generation energy storage systems owing to their prominent features such as low cost, environmental friendliness, high theoretical capacity (819 mAh g−1 and 5849 mAh cm−2), and low redox potential (−0.762 V vs. standard hydrogen evolution). However, several challenges to Zn metal anodes, such as uncontrollable dendritic growth, hydrogen evolution, and corrosion reactions in water-based electrolytes, result in unstable and poorly reversible electrochemical performance. Herein, we demonstrate a highly polar perovskite SrTiO3 (STO) layer introduced on Zn metal as an artificial layer promotes Zn2+ migration and suppresses the random dendrite growth in the mild aqueous electrolyte. STO-coated Zn anode (STO@Zn) highly improves the reversibility of electrochemical reaction in a symmetrically configured cell relative to bare Zn, with a significantly lower overpotential of 4000 h. Various electrochemical characterizations show uniform and rapid Zn2+ transport via the artificial STO layer. A full-cell test with VO2 cathode confirmed the excellent properties of STO@Zn, demonstrating reversible and stable performance with long service life. This study presents new insights into the design and development of promising Zn metal anodes for next-generation energy storage systems.