One-Step Electrochemical Synthesis of Co0.8Fe0.2Se@NiF Spheres Enclosed with Nanoparticles and Integrated Porous FeSe2@NiF as Electrode Materials for High-Performance Asymmetric Supercapacitor

Herein, we offer a new method to prepare Co0.8Fe0.2Se spheres enclosed with nanoparticles (Co0.8Fe0.2Se@NiF) as a cathode electrode and integrated porous FeSe2 (FeSe2@NiF) as an anode electrode to construct a high-performance asymmetric supercapacitor. The Co0.8Fe0.2Se@NiF electrochemical energy storage material shows a remarkable improvement of electrochemical performance containing low internal resistance, fast kinetics, good reversibility, considerable durability, and significant specific capacity (SC) of 309.31 mAh g(-1). The advancement in electrochemical performance of the FeSe2@NiF subtends a good SC of 227.34 mAh g(-1) and favorable durability. An asymmetric supercapacitor (ASC) device comprised of Co0.8Fe0.2Se@NiF as a cathode and FeSe2@NiF as an anode was assembled and evaluated. The assembled device shows an SC of 108.52 mAh g(-1) and energy density (ED) of 89.53 Wh kg(1-) at a power density (PD) of 824.95 W kg(1-). This improved electrochemical performance is dependent on the structural and intrinsic properties of both electrode materials, which can guarantee a hopeful potential for later generations of electronic systems.