Insertion of Calcium Ion into Prussian Blue Analogue in Nonaqueous Solutions and Its Application to a Rechargeable Battery with Dual Carriers

Abstract

We observed the first electrochemical insertion of Ca 2+ into Prussian blue analogue, MnFe(CN) 6, in nonaqueous solutions of Ca(CF 3 SO 3 ) 2 and various solvents including ionic liquid at 60 °C. The kinetics for the Ca 2+ insertion reaction were studied by cyclic voltammetry, and were compared to those of Na + intercalation. By coupling this phenomenon with metallic anodes, two energy storage devices were made. Ca anode produced a primary cell that operated at a voltage of around 2.0 V. When Mg plate was used as an anode, the negative active material associated with CF 3 SO 3 –, which we have already reported was newly formed at the surface of Mg plate. By combining the negative active material, we have fabricated a novel rechargeable battery using dual ion transport species of Ca 2+ for the cathode and CF 3 SO 3 – for the anode, and demonstrated that the battery showed repeated discharge/charge performance.