Iron-cobalt-nickel-copper-zinc (FeCoNiCuZn) high entropy alloy as positive electrode for high specific capacitance supercapacitor

Abstract

High entropy alloys (HEAs) are new-generation supercapacitive materials providing multiple active sites for enhanced electrochemical redox reactions. In this regard, we have successfully synthesized HEA comprising of Iron-Cobalt-Nickel-Copper-Zinc (Fe-Co-Ni-Cu-Zn) using induction melting and reduced its dimensions via ball milling. The ball-milled Fe-Co-Ni-Cu-Zn sample is throughly characterized by using basic structural and morphological techniques. A positive electrode is fabricated for supercapacitor application. This quinary HEA shows the highest gravimetric capacitance of 325.17 F g − 1 at 1 A g − 1 (3 M potassium hydroxide, aqueous electrolyte) in single electrode system. The asymmetric device also demonstrates energy density of 23.82 Wh kg−1 by consuming a power density of 325 W kg−1. Additionally, theoretical studies (DFT) shows that the electronic distribution of quinary Fe-Co-Ni-Cu-Zn elements in the alloy enhances chemical stability which is the reason for higher specific capacitance.