Unilamellar Metallic MoS₂/Graphene Superlattice for Efficient Sodium Storage and Hydrogen Evolution

Abstract

Unilamellar metallic nanosheets possess superiority for electrochemical energy storage and conversion applications compared to the few-layered bulk and semiconducting counterparts. Here, we report the utilization of unilamellar metallic 1T phase MoS 2 nanosheets for efficient sodium storage and hydrogen evolution through a MoS 2 /graphene superlattice. The superlattice-like assembly composed of alternately restacked unilamellar MoS 2 and modified reduced graphene oxide nanosheets was prepared by a facile solution-phase direct restacking method. As an anode for sodium storage, the MoS 2 /graphene superlattice anode exhibited an excellent rate capability of ∼240 mA h g −1 at 51.2 A g −1 and a stable reversible capacity of ∼380 mA h g −1 after 1000 cycles at 10 A g −1 . In addition, a low onset potential of ∼88 mV and a small Tafel slope of 48.7 mV decade −1 were attained for the hydrogen evolution reaction. Our findings are important for further developing the potential of 2D nanosheets for energy storage and conversion.

Chemical Mass Production of MoS2/Graphene van der Waals Heterostructure as a High‐Performance Li‐ion Intercalation Host

“…Differently, two new broad peaks in low‐angle region (marked by #1 and #2) are observed. The calculated d ‐spacing of peak #1 is 1.0–1.2 nm, which should be ascribed to the distance of adjacent MoS 2 monolayers . In addition, the d ‐spacing of peak #2 is about 0.5 nm, which is assigned to the distance between GR monolayer and MoS 2 monolayer .…”

“…Owing to the electrostatic attraction of opposite charges, the MoS 4 2− anions ionized from (NH 4 ) 2 MoS 4 can easily combine with the amines in PEI−GO, resulting in the modification of MoS 4 2− anions on PEI−GO basal plane (MoS 4 2− /PEI−GO). Moreover, stacked layers of MoS 4 2− /PEI−GO generate via the electrostatic attraction‐induced self‐assembly approach, as the electrostatic forces can trigger the spontaneous stack of the MoS 4 2− /PEI−GO layers . Subsequently, an annealing process was applied at 750 °C under H 2 /Ar atmosphere.…”

“…Vacuum deposition techniques are not practical for creating battery electrode materials, and the conventional mixing inevitably leads to the agglomeration of the same 2D components . Recently, several groups have synthesized the MoS 2 /GR heterostructure by self‐assembly approaches in solution . However, before these assembly processes, chemically exfoliated MoS 2 monolayers are needed to be prepared using dangerous and time‐consuming exfoliation procedures .…”

“…[17,18] Very recently, 2D van der Waals (vdW) heterostructure assembled by stacking MoS 2 and GR layers in hetero-layered architectures (MoS 2 /GR heterostructure) is proposed as a promising electrode material for LIBs and other metal ion batteries. [19][20][21][22][23] In comparison with the reported MoS 2 /GR composites, the large accessible surface of GR can ensure high MoS 2 loading in MoS 2 /GR heterostructure while keeping MoS 2 effectively exposed, which is critical for electrochemical applications. [24] In particular, the intimate face-to-face contact between MoS 2 and GR in MoS 2 /GR heterostructure can effectively endow MoS 2 with superior electron transport.…”

Dependence of the Properties of 2D Nanocomposites Generated by Covalent Crosslinking of Nanosheets on the Interlayer Separation: A Combined Experimental and Theoretical Study

“…To enhance the HER activity of MoS 2 , theoretical and experimental studies have proposed anchoring of Co atoms and cobaloxime on the inert basal plane of MoS 2 , engineering in the defects sites and using metallic 1T‐MoS 2 . Remarkable advances in heterostructure designs such as MoS 2 /graphene superlattices, nanosized MoS 2 /graphene hybrids, nonmetal plasmonic MoS 2 /TiO 2 heterostructure and MoS 2 ‐WS 2 heterostructures by physiochemical process have led to enhanced HER activity . Some studies have also revealed enhanced HER activity by virtue of active sites –…”