On the impact of Vertical Alignment of MoS2 for Efficient Lithium Storage

Abstract

Herein, we report energy storage devices, which are based on densely packed, vertically aligned MoS2 (VA-MoS2) or planar oriented MoS2 (PO-MoS2) and compare their electrochemical performances. The VA-MoS2 films have been processed by chemical vapor deposition (CVD) to reach unprecedented micron-scale thick films while maintaining the vertical alignment for the whole thickness. The VA-MoS2 and the PO-MoS2 films form a high-performance Li-ion electrode, reaching the theoretical limits of reversible capacity for this material (800 mAh/g; twice the specific capacity of graphite). The vertical alignment allows faster charge-discharge rates while maintaining a high specific capacity (C-rate measurements). Noteworthy, the reversible cycling of the Li-ion electrode also benefits from the vertical alignment. In this article, we present the full synthesis, structural and electrochemical characterization of VA-MoS2 along with the properties of PO-MoS2 to deconvolute the intrinsic properties of MoS2 from the influence of the layers’ orientation.

Large‐Scale and Robust Multifunctional Vertically Aligned MoS2 Photo‐Memristors

“…Atomic‐thin semiconductors, such as the transition metal dichalchogenide (TMDC) family have attracted great scientific, and technological attention due to their interesting physical and chemical properties, which make them promising candidates in a wide range of applications, such as nanoeletcronics, [ 7 ] optoelectronics, [ 8 ] catalysis, [ 9 ] and energy storage. [ 9c–e,10 ] Such atomic crystals were also suggested as solid electrolytes in resistive switching devices. [ 1a,11 ] To our knowledge, only planar single‐ and few‐layer 2D materials were implemented into memristor devices with top and bottom metal contacts.…”

“…Vertically aligned (VA) TMDCs were shown to be formed by the calchogenization of transition metal thin films or foils. [ 9a,13 ] Thin films of VA‐MoS 2 , [ 9a,10,13a,b ] ‐MoSe 2 , [ 13b ] and ‐WSe 2 [ 13c ] were reported and their electronic and catalytic properties tested. These films therefore, offer some interesting features, not available on planar few‐layer TMDCs.…”

“…Second, the VA‐TMDC configuration can be advantageous in a vertical memristive device due to the enhanced ionic/cationic diffusion in between vdW layers. [ 9a,d,e,10 ] Furthermore, such VA‐TMDCs can in principle be doped/alloyed in situ during the sulfurization process, therefore, adding functionality to the films. [ 9a,14 ]…”

Morphological Evolution of Vertically Standing Molybdenum Disulfide Nanosheets by Chemical Vapor Deposition

“…Li found that larger, dense exposed edges of vertical MoS 2 sheets can lead to a more active HER electro-catalyst [ 15 ]. However, while extensive studies have been devoted to two-dimensional materials which lie flat on the substrates [ 18 , 19 , 20 , 21 ], few reports have been developed regarding the growth of vertically standing MoS 2 nanosheets [ 6 , 11 , 22 , 23 , 24 , 25 , 26 ]. The growth of such vertically standing nanosheets is still challengeable, and more efforts should be made to explore the growth characteristics of nanosheets.…”

Preparation of MoS2 Nanopetals by RF Magnetron Sputtering and Electron-Beam Irradiation

“…4(c) and 4(d), EBI-treated MoS 2 grew uniformly with exposed edge sites. Since these vertically exposed edge sites of MoS 2 play an important role in improving catalytic activity and sensing property [16], we expected EBI-treated MoS 2 to be a potential candidate for gas sensor and hydrogen evolution reaction (HER). Furthermore, because morphology of MoS 2 is significantly affected by fabrication parameters [14,15], optimized sputtering and EBI parameters for more dense and uniform morphology would be required to application of EBI-treated MoS 2 in gas sensor and HER.…”