Microwave-assisted reflux synthesis of spherical Co2Fe(CN)6 nanoparticles for high-performance asymmetric supercapacitors

The open framework materials with the Prussian blue structure facilitate the insertion of monovalent K+ ions and exhibit high capacitive performance. In this regard, the spherical Co2Fe(CN)6 (Co-HCF) nanoparticles were synthesized by the microwave-assisted reflux method. The X-ray diffraction pattern confirms the cubic structure, and the transmission electron microscopy images reveal the formation of spherical sized particles. The cyclic voltammetry analysis corroborated the reversibility of the electrode and delivered the specific capacitance of 1131 F g−1 at 2 mV s−1 in 1 M KNO3 electrolyte. Further, the 2 V asymmetric supercapacitor (Co-HCF//AC) was fabricated with activated carbon, which delivers the specific capacitance of 50 F g−1 at 10 mV s−1 and the energy density of 24.06 Wh kg−1 at the power density of 103.7 W kg−1 at 1 A g−1 with cycling stability of nearly 84% over 1000 cycles.