In situ construction of multifunctional metaphosphate interphase enabling stable zinc anode with fast Zn2+ transport kinetics

Abstract

Aqueous zinc-ion batteries have significant potential application in large-scale energy storage due to their high safety, affordability, and high energy density. However, serious dendrite growth and side reactions, primarily caused by uneven zinc deposition and direct electrolyte contact, significantly reduce the lifespan of the Zn metal anode. Here, we introduce a multifunctional zinc metaphosphate interphase on ultrahighly oriented Zn with a (002) texture. It is fabricated in situ on Zn foil with no boundaries through a straightforward one-step annealing method. The highly conductive zinc metaphosphate interphase is thin with approximately 40 nm thickness. It facilitates rapid Zn-ion transport kinetics and promotes uniform zinc deposition through an epitaxial growth strategy. Additionally, the insulating and stable interphase inhibits corrosion and the hydrogen evolution reaction. As a result of these advantages, the modified Zn foils demonstrate excellent electrochemical performance. In symmetric cells, the zinc metaphosphate interphase-modified Zn anode operates continuously for over 1400 h at an ultrahigh current density of 100 mA cm⁻² and has an outstanding cycle lifespan of 5900 h at 0.5 mA cm⁻². This sustainable protection strategy for the Zn anode lays the foundation to develop high-performance electrodes for aqueous Zn-ion batteries.