Nano-Nest Type Porous NiCo₂S₄@polyindole Core–Shell Array: Efficient Energy Storage Supercapacitor Device

Abstract

Designing materials in appropriate nanoarchitectures can improve several electrochemical properties to yield power storage devices. Here an inorganic−organic core−shell nanostructure in an appropriate morphology has been designed to improve ion-transportation as well as ion diffusion mechanism for possible application in supercapacitor materials and eventually in a solid state supercapacitor. The NiCo 2 S 4 @PI core/shell electrode material shows high specific capacitance with a 92% contribution from surface-controlled process, due to the presence of dual active metal sites for ion adsorption. Consequently, the fabricated prototype asymmetric supercapacitor delivered a high specific capacitance with high energy density and power density. Additionally, the device exhibits an exceptionally high capacitance retention of 100%. The device's performance under real-life conditions has also been demonstrated. This work significantly shows that surface morphology modification by adopting a core−shell architecture can substantially enhance the ion transport process and is an effective strategy to improve the overall electrochemical energy storage performance.