Vertically Oriented Arrays of ReS₂ Nanosheets for Electrochemical Energy Storage and Electrocatalysis

Abstract

Transition-metal dichalcogenide (TMD) nanolayers show potential as high-performance catalysts in energy conversion and storage devices. Synthetic TMDs produced by chemical-vapor deposition (CVD) methods tend to grow parallel to the growth substrate. Here, we show that with the right precursors and appropriate tuning of the CVD growth conditions, ReS2 nanosheets can be made to orient perpendicular to the growth substrate. This accomplishes two important objectives; first, it drastically increases the wetted or exposed surface area of the ReS2 sheets, and second, it exposes the sharp edges and corners of the ReS2 sheets. We show that these structural features of the vertically grown ReS2 sheets can be exploited to significantly improve their performance as polysulfide immobilizers and electrochemical catalysts in lithium-sulfur (Li-S) batteries and in hydrogen evolution reactions (HER). After 300 cycles, the specific capacity of the Li-S battery with vertical ReS2 catalyst is retained above 750 mA h g(-1), with only ∼0.063% capacity decay per cycle, much better than the baseline battery (without ReS2), which shows ∼0.184% capacity decay per cycle under the same test conditions. As a HER catalyst, the vertical ReS2 provides very small onset overpotential (<100 mV) and an exceptional exchange-current density (∼67.6 μA/cm(2)), which is vastly superior to the baseline electrode without ReS2.

Ultrahigh, Ultrafast, and Self‐Powered Visible‐Near‐Infrared Optical Position‐Sensitive Detector Based on a CVD‐Prepared Vertically Standing Few‐Layer MoS2/Si Heterojunction

“…The distance between the two peaks in the line intensity profile shown in the bottom of Figure 2e is ≈0.307 nm, which matches well with the value of the unit cell parameter of MoS 2 39. 2D materials with high‐quality vertically oriented few‐layer structures have been reported to be ideal materials for photodetectors, energy storage, catalysis, and edge emitter devices because of their high active surface areas, strong light absorptions, and quick longitudinal intralayer transport speeds 34, 35, 36, 37, 40, 41, 42. Therefore, these V‐MoS 2 nanosheets may also have great potential applications in multifarious fields.…”

“…However, vertically oriented multilayer MoS 2 , which has the advantages of both strong light absorption and quick longitudinal in‐plane transport, may show huge potential in optoelectronic devices; e.g., in 2015, Wang et al first deposited the vertically standing layered MoS 2 directly on Si substrate to form MoS 2 /Si heterojunction photodetector by magnetron sputtering and realized an extremely high detectivity (≈10 13 Jones) and an ultrafast response time (≈3 µs) 33. Considering the outstanding properties and great potential in optoelectronic devices, recently, researchers have begun trying to synthesize other 2D materials of this vertically layered structure, and several large‐area, high‐quality, and vertically oriented few‐layered 2D nanosheets have been successfully prepared by chemical vapor deposition (CVD) 34, 35, 36, 37. Notably, compared with other preparation methods, the quality of CVD‐prepared MoS 2 should be much better due to the relatively intact layered structure and fewer defects.…”

Advent of 2D Rhenium Disulfide (ReS2): Fundamentals to Applications

“…[106] It has shown that ReS2 can be exploited as polysulfide immobilizer, and therefore, used to suppress the dissolution of polysulfides and enhance the cycle stability of the Li-S batteries. [107] The effect of ReS2 in (Figure 12 c). Moreover, binding polysulfides showed higher binding energy (2.24 to 2.66 eV) on ReS2 surfaces than that of carbon (~0.5 to 1 eV).…”

“…[121] Like other TMDs, ReS2 has shown 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 good HER performance -better than the more commonly used TMDs. [107,122] Gao et al [107] has tested HER on CVD grown ReS2@Au, and found that it exhibited ~ 200 mV less overpotential (η) than bare Au. Further decrease in overpotential (η < 100 mV) was achieved after lithiation using n-butyl lithium treatment (Figure 15 a).…”

Narrow-band anisotropic electronic structure of ReS2

“…This opens the exciting prospect to achieve optoelectronic functionality from bulk ReX 2 of a form that can only be realized by complex fabrication of single-layer samples and devices in group VI semiconducting TMDCs. Coupled with a pronounced anisotropy in their measured optical and electrical properties [7][8][9][10], ReX 2 materials are therefore important compounds for expanding the functionality of the TMDC class, and they have potential for next-generation technologies [11,12]. The electronic structure underpinning their striking optoelectronic properties, however, remains almost completely unexplored experimentally to date.…”