Preparation of nanowire-like core–shell Ni3Se4@NiCo2O4/NF composite electrodes for high-performance supercapacitors

Double transition metal oxides and oxygen group element compounds are widely used in supercapacitor electrode materials. In this work, nanowire-like NiCo 2 O 4 was synthesised using a hydrothermal method, and Ni 3 Se 4 was deposited on a nickel foam using NiCo 2 O 4 as the base material utilizing electrodeposition. Composites exhibit superior electrochemical properties with lower impedance values than single materials. Ni 3 Se 4 @NiCo 2 O 4 /NF composite showed an areal capacitance of 1404.17 mF cm −2 at 1 mA cm −2 , outperforming both NiCo 2 O 4 /NF (735.83 mF cm −2 ) and Ni 3 Se 4 /NF (523.5 mF cm −2 ) electrodes. The asymmetric supercapacitor is formed by using Ni 3 Se 4 @NiCo 2 O 4 /NF composite electrode as anode and carbon electrode as cathode with 3 M KOH solution as electrolyte. The device has an energy density of 0.0864 mWh cm −2 at a power density of 0.8 mW cm −2 and 0.0231 mWh cm −2 at a power density of 7.996 mW cm −2 . The capacitance retention of this asymmetric supercapacitor remained 91.76% after 5000 cycles at a current density of 10 mA cm −2 .