Zn 2+ /Mo 6+ Modulated Phase Structure and Morphology of FeCoNi High-Entropy Hydroxide for Boosted Supercapacitor Electrode Performance

Abstract

FeCoNi-based hydroxides are considered as great potential supercapacitor electrode materials, but their practical application is hindered by unsatisfactory specific capacitance and lifespan. In this study, FeCoNiMoZn high entropy hydroxide was fabricated via a facial one-pot hydrothermal method. The experimental results reveal the introduction of Mo and Zn can not only thin the nanosheets and create defects but also change the phase structure from Ni(OH) 2 to Zn(OH) 2 , achieving an ultra-high specific capacitance and excellent cycling stability. The specific capacitance of FeCoNiMoZn high entropy hydroxide electrode reaches 9.96 F cm -2 at 5 mA cm -2 and 78.0 % initial capacitance retains in 5000 cycles at 50 mA cm -2 in 2 mol L -1 KOH solution. This study clarifies the effects of phase structure transition and vacancy regulation on electrochemical performance, offering a new pathway for designing advanced electrode materials.