Ni-doped cobalt hexacyanoferrate microcubes as battery-type electrodes for aqueous electrolyte-based electrochemical supercapacitors

Ni-doped cobalt hexacyanoferrate (NiCoHCF) microcubes were fabricated through co-precipitation method at room temperature. The doping of nickel ions shows positive effect on the nanostructure and electrochemical properties of the cobalt hexacyanoferrate (CoHCF). The results of scanning electron microscopy (SEM) and X-ray diffractometer (XRD) indicate that the doping of nickel ions can reduce the grain size of CoHCF microcubes. The as-synthesized NiCoHCF microcubes are studied as electrode materials for supercapacitor showing a high specific capacitance of 129.4 mAh g(-1) (466 F g(-1)) at a scan rate of 5 mV s(-1) and good cycling stability of retaining 87.9% after 2000 cycles in 1 M Na2SO4 under 0-1 V at 2 A g(-1) when the molar ratio of nickel-cobalt is 1:2 mmol. The enhanced electrochemical performance of NiCoHCF benefits from the strong synergistic utilization of nickel ions and cobalt ions. (C) 2019 Elsevier B.V. All rights reserved.