Potassium cobalt hexacyanoferrate nanocubic assemblies for high-performance aqueous aluminum ion batteries

• The K 2 CoFe(CN) 6 is equipped with a nanocubic assembled structure. • The as-prepared aqueous AIB exhibited well discharge capacity and cycle stability. • Possible charge-discharge mechanism of K 2 CoFe(CN) 6 is elucidated. Prussian blue analogues are considered as a class of extremely promising electrode materials for various energy storage devices. Here, the potassium cobalt hexacyanoferrate (K 2 CoFe(CN) 6 ) with a nanocubic assembled structure was successfully synthesized via a one-step hydrothermal method and low-temperature calcination operation; this material is employed as the working electrode for aqueous aluminum ion batteries (AIBs). To some extent, such a 3D open-framework structure accelerated the electronic and ionic transmission and optimized the electrochemical properties. The as-prepared K 2 CoFe(CN) 6 demonstrated a reversible discharge capacity of 50 mA h g −1 at a of 0.1 A/g and showed a desirable cycling stability, which makes it a feasible electrode material for aqueous AIBs.