Zinc hexacyanoferrate as cathode material for aqueous copper-ion batteries

Abstract

Rechargeable aqueous multivalent ion batteries have attracted increasing attention as an alternative energy storage system for Lithium-ion batteries. In this research, zinc hexacyanoferrate (ZnHCF) is demonstrated as a high-performance cathode material for aqueous copper-ion batteries. It is worth noting that ZnHCF displays remarkable cycling performance with capacity of 55.6 mAh g–1 and a capacity retention of ∼95% after 3000 cycles. Furthermore, ex-situ XRD reveals the essence of copper ion de-/intercalation mechanism and irreversible structure transition of ZnHCF. Prussian blue analogs are a viable solution in copper- ion batteries despite the problem of ZnHCF dissolution in aqueous solutions.