Establishing aqueous zinc-ion batteries for sustainable energy storage

Aqueous rechargeable Zn-ion batteries (ARZIBs) have been becoming a promising candidates for advanced energy storage owing to their high safety and low cost of the electrodes. However, the poor cyclic stability and rate performance of electrodes severely hinder their practical applications. Here, an ARZIBs configuration consisting of Cr³⁺-substituted Cu-Rich Prussian blue analogues (CuCrFe(CN)₆) cathode, electrodeposited zinc nanosheets on copperclad carbon framework (ZnNS@CuCF) anode, and Zn(OTf)₂-based electrolyte with ethylene sulfate (DTD) that are proposed. Combining the in situ characterization, ex situ synchrotron radiation and density functional theory (DFT) calculations, the Cr³⁺-substitution and K⁺ extraction can effectively lower the band gap of the electrodes and Zn ion diffusion activation energy. Thus, the assembled ARZIBs system delivers the excellent electrochemical performance such as large specific capacity of 183.9 mAh g⁻¹, high energy density of 239.2 Wh kg⁻¹ and impressive cyclic stability with the capacity retention of 92.4% after 13,000 discharging/charging cycles.