Mixed-phase MoS₂ decorated reduced graphene oxide hybrid composites for efficient symmetric supercapacitors

In this work, we demonstrated the phase-tuned MoS₂ layers (2H- MoS₂, 1 T- MoS₂, and 2H/1 T-MoS₂) using a one-pot reaction, scientifically significant due to their impermeable characteristics. Strongly-bonded, vertically-aligned layers were perceived by transmission electron microscopy (TEM) for 2H/1 T-MoS₂ layers. The spacing between the two layers was expanded to 0.67 nm, which is favorable for intercalation process. Further, mixed-phase MoS₂ sheets were successively blended with reduced graphene oxide (rGO) to form 2H/1 T-MoS₂@rGO hybrid. Spectroscopic studies verified the formation of phase-tuned MoS₂ and 2H/1 T-MoS₂@rGO hybrid. The resulting 2H/1 T-MoS₂@rGO hybrid TEM micrograph shows the layered MoS₂ lattices decorated rGO nano-structure. Symmetric supercapacitors constructed from 2H/1 T-MoS₂@rGO hybrid electrodes demonstrated improved storage capacity with solid pseudo-capacitive behavior compared to the pure phases. Surface-modified 2H/1 T-MoS₂@rGO nanostructures exhibited a high energy density of 55 Wh·kg⁻¹ at a power density of 3 kW·kg⁻¹ with a symmetric capacitance of 275 F·g⁻¹ at a current density of 1 A·g⁻¹, along with an excellent cyclic constancy (~97% capacity after 5000 cycles).