CoFe₂O₄@Carbon Spheres Electrode: A One‐Step Solvothermal Method for Enhancing the Electrochemical Performance of Hybrid Supercapacitors

Abstract

Abstract Constructing electrode materials with high energy densities are the effective way to develop asymmetric supercapacitor devices. Therefore, the inlay of conductive materials into pseudocapacitive constituents is a practical approach to increase the performance of supercapacitor electrodes. Herein, we declare a facile one‐step as an economic strategy for tailoring carbon spheres (CSs) impregnated by CoFe 2 O 4 to form a CoFe 2 O 4 @CSs composite. The CoFe 2 O 4 @CSs composite was fully characterized by X‐ray diffraction (XRD), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM), which evidenced that CoFe 2 O 4 nanoparticles were densely cored inside the carbon spheres. Moreover, the electrochemical characterization of the CoFe 2 O 4 @CSs composite was manifested high specific capacitance of (600 F/g) at a current density (1 A/g), high performance rate, and cycling stability. CoFe 2 O 4 @CSs has achieved capacitance retention of 94.1 % after 5000 charge/discharge cycles at a current density of 20 mA/g. The device‐based asymmetric supercapacitors were found to improve the energy density to 27.08 Wh/kg at a power density of 750 W/kg with 99 % capacitance retention, which is higher than the values previously reported. The exceptional performance of CoFe 2 O 4 @CSs composites gives high priority for such materials in variant electrochemical fields, owing to the harmony between CoFe 2 O 4 nanoparticles and carbon spheres.