Open-framework aluminum hexacyanoferrate as a cathode material for high voltage aqueous zinc-ion batteries: effect of Al3+ cations on three-phase transition of AlFe(CN)6

KAlFe(CN) 6 (AlHCF) is synthesized and its electrochemical performance in aqueous ZIBs is first reported. The Zn/AlHCF full cell exhibited a record-high output voltage of 1.8 V. A rare three-phase coexistence phenomenon is demonstrated in AlHCF.