Mixed 1T–2H Phase MoS₂/Reduced Graphene Oxide as Active Electrode for Enhanced Supercapacitive Performance

Abstract

A hybrid aerogel, composed of MoS 2 sheets of 1T (distorted octahedral) and 2H (trigonal prismatic) phases, finely mixed with few layers of reduced graphene oxide (rGO) and obtained by means of a facile environment-friendly hydrothermal cosynthesis, is proposed as electrode material for supercapacitors. By electrochemical characterizations in three- and two-electrode configurations and symmetric planar devices, unique results have been obtained, with specific capacitance values up to 416 F g –1 and a highly stable capacitance behavior over 50000 charge–discharge cycles. The in-depth morphological and structural characterizations through field emission scanning electron microscopy, Raman, X-ray photoelectron spectroscopy, X-ray diffraction, Brunauer–Emmett–Teller, and transmission electron microscopy analysis provides the proofs of the unique assembly of such 3D structured matrix. The unpacked MoS 2 structure exhibits an excellent distribution of 1T and 2H phase sheets that are highly exposed to interaction with the electrolyte, and so available for surface/near-surface redox reactions, notwithstanding the quite low overall content of MoS 2 embedded in the reduced graphene oxide (rGO) matrix. A comparison with other “more conventional” hybrid rGO-MoX 2 electrochemically active materials, synthesized in the same conditions, is provided to support the outstanding behavior of the cosynthesized rGO-MoS 2 .