Preparation and Electrochemical Characterization of Hollow Hexagonal NiCo₂S₄Nanoplates as Pseudocapacitor Materials

In this study, the binary transition metal sulfide NiCo 2 S 4 with a novel hollow hexagonal nanoplate (HHNs) structure has been synthesized through a sacrificial template method based on the Kirkendall effect. The hollow nanoplates have an average diameter of about 200 nm, thickness of about 50 nm, and shell thickness of about 10 nm. The resulting samples were characterized by means of XRD, XPS, EDX, SEM, TEM, and HRTEM. The electrochemical characterization results demonstrate that NiCo 2 S 4 hollow hexagonal nanoplates exhibit a high specific capacitance of 437 F g –1 in a 3 M KOH aqueous electrolyte at a current rate of 1 A g –1, along with a superior rate capability and Coulombic efficiency stability, indicating their potential application as electrode materials for supercapacitors.