Rational design of multiple prussian-blue analogues/NF composites for high-performance surpercapacitors
In this project, a series of NiCoxFe1-x-PBA/NF (nickel foam) electrodes were successfully fabricated with different ratios of Co and Fe through in-situ chemical etching process. Their structures and morphology were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopes (SEM). Remarkably, this novel series of composites exhibit excellent supercapacitor performance. Among them, NiCo-PBA/NF electrode exhibits the best electrochemical performance with an area capacitance of 2242 mF cm-2 at 1 mA cm-2 in 3 M KOH solution and good cycling stability. Furthermore, asymmetric supercapacitor cells with NiCo-PBA/NF as the positive electrode and active carbon coated on the nickel foam as the negative electrode delivers very high energy density of 39.4 Wh kg-1 and high power density of 4003 W kg-1, which far exceeds other devices reported previously. This work highlights the designing strategy of such composite materials with optimized synergistic effect, which greatly promotes the supercapacitor development.