Formation of Hierarchical Core-Shell Hollow Co3s4@Nico2s4 Nanocages with Enhanced Performance for Supercapacitor

Abstract

Metal-organic frameworks (MOFs) have sparked considerable interest as prospective metal precursors or sacrificial templates to design high-performance supercapacitor electrode materials. Here Co 3 S 4 @NiCo 2 S 4 nanocage supercapacitor electrode material with dual-core layer hollow structure was successfully constructed through an appropriate ion-exchange strategy of MOFs and the subsequent vulcanization treatment. The specific capacitance of the Co 3 S 4 @NiCo 2 S 4 electrode was up to 601 C g −1 at 1 A g −1 current density, and it was still able to achieve 80% rate performance when there was a tenfold difference between low current density and high current density. The integrated Co 3 S 4 @NiCo 2 S 4 //AC asymmetric supercapacitor achieved 58 Wh Kg −1 of energy density at 750 W kg −1 of power density. The asymmetric supercapacitor retained 89% of its capacitance after 3000 galvanostatic charge-discharge cycles. In this study, the individual nanostructure and exceptional electrochemical properties of MOFs derivatives provide a rational strategy for developing high-energy-density supercapacitor electrode materials.

Keywords: MOFs, Hollow structure, Co3S4@NiCo2S4, Supercapacitor