In-situ-grown Co-doped Ni-hexacyanoferrate/Ni-foam composites as battery-type electrode materials for aqueous hybrid supercapacitors

Abstract

Prussian blue analogues (PBAs), a class of metal–organic materials, are gaining much importance as battery-type electrode materials for hybrid supercapacitors (HSCs), owing to their open-framework structure and high power density. In this work, which considers Ni-hexacyanoferrate (NiHCF) as a PBA subsystem, Co-doped NiHCF/ Ni-foam (NF) composites are synthesized through a simple hydrothermal process and their structural, morphological, and electrochemical properties are studied. The Co 0.7 Ni 0.3 HCF/NF electrodes exhibit improved battery-like behavior with excellent electrochemical performance, cycling stability, and specific capacitance. The HSC fabricated with Co 0.7 Ni 0.3 HCF/NF as the positive electrode and an activated carbon cloth as the negative electrode produces a high power density of 3938 W kg −1 at an energy density of 13 Wh kg −1 . These results emphasize that the proposed composite is a promising candidate as an electrode material and that it is well-suited for the development of supercapacitors. • Co-doped NiHCF/ Ni-foam (NF) composites are synthesized through one pot hydrothermal process. • These composites exhibited battery-like behavior with excellent electrochemical performance. • The Co 0.7 Ni 0.3 HCF/NF composite displays excellent specific capacity of 623 mAh g −1 at 1 A g −1 . • The constructed hybrid supercapacitor device displayed good cycling performance over 5000 cycles.