Vertically Aligned Molybdenum Disulfide for Efficient Lithium Storage

Layered transition-metal disulfides (LTMDs) have played a prominent role in the development of electronic, energy conversion and storage devices. Molybdenum disulfide (MoS2) has been widely investigated as a highly efficient alternative to existing materials. Most fabrication pathways of MoS2 focus on its planar growth on various substrates to reach high-quality layers with planar orientation (PO). Nevertheless, in most energy-storage applications, the most relevant orientation is the vertical alignment (VA) of well-defined layers. VA growth paves the way to highly dense devices with exposed active sites on the surface. Here, the chemical vapor deposition (CVD) process has been investigated to grow 2H-MoS2 films hundreds of nanometers thick with VA stacking. The films show large domains of perfectly aligned layers with high crystallinity and density and low surface roughness. CVD-grown VA-MoS2 films show superior behavior in lithium storage, with stable capacity even at a high current density compared to PO-MoS2 films. The VA-MoS2 films show a high reversible capacity of 800 mAh/g for lithium storage, which corresponds to the full conversion to Mo and Li2S.

HR-TEM images of VA-MoS2 Capacity of VA-MoS2 compare to PO-MoS2