Binder-free copper hexacyanoferrate electrode prepared by pulse galvanostatic electrochemical deposition for aqueous-based Al-ion batteries

Copper hexacyanoferrate (CuHCF) nanoparticles with tunnel-like Prussian blue structure were deposited on a graphite substrate via pulse galvanostatic electrodeposition at 25 mA cm-2 with two 0.1 speriods of on/off-time. The prepared electrodereversibly showed the intercalation/de-intercalation ability of Al ions in aqueous solution. The crystal structure of the as-prepared CuHCF film was characterized by X-ray diffraction (XRD) analysis. The surface morphology of the film was examined by a field-emission scanning electron microscope (FESEM). Moreover, the electrochemical energy storage performance of the prepared binder-free electrode was inspected by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) measurements at various rates in aqueous-based aluminum sulfate electrolyte. The CuHCF was verified that canbe a promising cathode material for the aqueous Alion batteries. The prepared CuHCF electrode exhibited a high specific capacity of 77.7 mAh g1 and a good rate capability with 67.1% capacitance retention rate at a current density of 50 mA g1and 400 mA g1, respectively. Furthermore, after 400 cycles at 400 mA g1, the electrode showed a good cycle performance with a capacity retention rate of 74.4%.