Interface storage of vanadium based materials in zinc-ion batteries

Abstract

In the study of aqueous zinc-ion batteries, vanadium-based materials, as typical insertion-type cathode materials, present an inherent contradiction in simultaneously achieving high energy density (deep-level insertion) and high power density (fast kinetics), a phenomenon referred to as the “Ragone conflict”. While constructing artificial interfaces has been shown to enhance both capacity and kinetics, the underlying mechanisms of these improvements primarily rely on qualitative understanding. In this brief focus article, we elucidate the interface storage model of vanadium-based materials, providing a more quantitative approach to describing interface kinetics and specific capacity. In some reports involving vanadium-based heterostructures, there is evidence suggesting that zinc storage may rely on interfacial storage in specific materials, accompanied by reversible interfacial bond rearrangement (interfacial breathing) and decoupled ionic/electronic transport (job-sharing), thereby achieving more and faster zinc ion storage, providing an effective solution to the Ragone conflict.