Reversible Aluminum‐Ion Intercalation in Prussian Blue Analogs and Demonstration of a High‐Power Aluminum‐Ion Asymmetric Capacitor

Electroanalytical, structural, and microanalytical techniques are combined to demonstrate the first clear and convincing case of electrochemical storage by Al-ion intercalation in a Prussian blue analog host. In addition, a high power asymmetric capacitor using Al-ion intercalation is demonstrated. Al, Fe, and Cu elemental maps of intercalated Al0.18 K0.02Cu[Fe(CN)6]0.7·3.7H2O obtained by transmission electron microscopy (TEM) energy-dispersive X-ray spectroscopy (EDX) area scan are shown.