A novel cobalt hexacyanoferrate/multi-walled carbon nanotubes nanocomposite: Spontaneous assembly synthesis and application as electrode materials with significantly improved capacitance for supercapacitors

Abstract Vast improvement of the capacitance of supercapacitors without sacrificing high power density and cycle performance brings bright application prospect. Here, a novel cobalt hexacyanoferrate/multi-walled carbon nanotubes (CoHCF/MWCNTs) nanocomposite is prepared by a simple and facile approach and further investigated as electrode materials for supercapacitors. The physical properties of as-prepared materials are characterized by XRD, FTIR, Raman and FE-SEM techniques. Furthermore, electrochemical performances of as-prepared materials are investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy in 1.0 M Na 2 SO 4 electrolyte. It is shown that as-prepared CoHCF/MWCNTs (25.0 wt% of MWCNTs) nanocomposite based electrode exhibits the best electrochemical performances, including higher specific capacitance/capacity (648.5 F g −1 /810.6 C g −1 at 1.4 A g −1 ), good rate capability (648.5 F g −1 /810.6 C g −1 and 436.3 F g −1 /545.3 C g −1 at 1.4 A g −1 and 15 A g −1 , respectively) and excellent cycling stability (94.3% capacitance retention after 3000 cycles at 2.0 A g −1 ) in all as-prepared electrodes. The results demonstrate that as-prepared CoHCF/MWCNTs nanocomposite is a promising candidate for electrochemical energy storage.