Enhanced electrochemical performance of MoS2@CdS@GO ternary heterostructures for asymmetric supercapacitors

Abstract

Graphene oxide (GO) combined with transition metal sulfides has been identified as a promising approach for energy storage, offering improved properties over pure transition metal sulfides. In this work, a ternary heterostructure of MoS₂, CdS, and GO (MoS₂@CdS@GO) was synthesized via a hydrothermal method. The structure was characterized using XRD, XPS, EDAX, Raman spectroscopy, UV–visible spectroscopy, and TEM. TEM images revealed that CdS nanoparticles are surrounded by MoS₂ and GO sheets. UV analysis confirmed that adding MoS₂@CdS to GO reduced the band gap of the composite. Electrochemical testing of GO, CdS, MoS₂, MoS₂@GO, MoS₂@CdS, and MoS₂@CdS@GO showed that the MoS₂@CdS@GO composite achieved an impressive specific capacitance of 1262 F/g at a scan rate of 6 mV/s and retained 91 % of its capacitance after 5000 cycles. This was attributed to the enhanced performance of MoS₂@GO in combination with CdS, which provides greater ion buffering and better charge storage. In practical terms, an asymmetric supercapacitor (ASC) utilizing MoS₂@CdS@GO showed 86.9 % capacitance retention after 5000 cycles and reached an energy density of 40.69 Wh/kg at a power density of 586.68 W/kg, highlighting its potential for energy storage devices.