Mumukshu D. Patel

Directly deposited MoS2 thin film electrodes for high performance supercapacitors

Two dimensional (2D) layered materials have recently attracted significant research interest owing to their unique physical and chemical properties for efficient electrochemical energy storage devices. Here, we present a neoteric approach to fabricate high performance MoS2 thin film supercapacitor electrodes by using a direct magnetron sputtering technique. The novel three-dimensional (3D) porous structure of the MoS2 film exhibits an excellent capacitance of ∼330 F cm−3 along with a high volumetric power and energy density of 40–80 W cm−3 and 1.6–2.4 mW h cm−3, respectively. Moreover, the optimized MoS2 electrode shows an outstanding cyclic stability, yielding capacitance retention over 97% after 5000 cycles of charging/discharging. The contemporary approach to MoS2 supercapacitor electrode fabrication will enable new opportunities in flexible electronic and energy devices.

2D MoS 2 as an efficient protective layer for lithium metal anodes in high-performance Li–S batteries

Among the candidates to replace Li-ion batteries, Li–S cells are an attractive option as their energy density is about five times higher (~2,600 Wh kg−1). The success of Li–S cells depends in large part on the utilization of metallic Li as anode material. Metallic lithium, however, is prone to grow parasitic dendrites and is highly reactive to several electrolytes; moreover, Li–S cells with metallic Li are also susceptible to polysulfides dissolution. Here, we show that ~10-nm-thick two-dimensional (2D) MoS2 can act as a protective layer for Li-metal anodes, greatly improving the performances of Li–S batteries. In particular, we observe stable Li electrodeposition and the suppression of dendrite nucleation sites. The deposition and dissolution process of a symmetric MoS2-coated Li-metal cell operates at a current density of 10 mA cm−2 with low voltage hysteresis and a threefold improvement in cycle life compared with using bare Li-metal. In a Li–S full-cell configuration, using the MoS2-coated Li as anode and a 3D carbon nanotube–sulfur cathode, we obtain a specific energy density of ~589 Wh kg−1 and a Coulombic efficiency of ~98% for over 1,200 cycles at 0.5 C. Our approach could lead to the realization of high energy density and safe Li-metal-based batteries.An ~10-nm-thick MoS2 layer stabilizes lithium metal anodes and the composite can be used in full-cell Li–S batteries with enhanced performances.

Vertically oriented MoS2 nanoflakes coated on 3D carbon nanotubes for next generation Li-ion batteries

The advent of advanced electrode materials has led to performance enhancement of traditional lithium ion batteries (LIBs). We present novel binder-free MoS2 coated three-dimensional carbon nanotubes (3D CNTs) as an anode in LIBs. Scanning transmission electron microscopy analysis shows that vertically oriented MoS2 nanoflakes are strongly bonded to CNTs, which provide a high surface area and active electrochemical sites, and enhanced ion conductivity at the interface. The electrochemical performance shows a very high areal capacity of ~1.65 mAh cm-2 with an areal density of ~0.35 mg cm-2 at 0.5 C rate and coulombic efficiency of ~99% up to 50 cycles. The unique architecture of 3D CNTs-MoS2 is indicative to be a promising anode for next generation Li-ion batteries with high capacity and long cycle life.

Publisher Correction: 2D MoS 2 as an efficient protective layer for lithium metal anodes in high-performance Li–S batteries

In the version of this Article originally published, a technical error in typesetting led to the traces in Fig. 3a being trimmed and made to overlap. The figure has now been corrected with the traces as supplied by the authors; the original and corrected Fig. 3a are shown below. Also, in the last paragraph of the section “Mechanistic study on Li diffusion in MoS2” the authors incorrectly included the term ‘high-concentration’ in the text “the Li diffusion will be dominated by high-concentration Li migration on the surface of T-MoS2 with a much smaller energy barrier (0.155 eV) to overcome”. This term has now been removed from all versions of the Article. Finally, the authors have added an extra figure in the Supplementary Information (Supplementary Fig. 19) to show galvanostatic tests at 1 and 3 mA cm–2 for the MoS2-coated Li symmetric cells. The caption to Fig. 3 of the Article has been amended to reflect this, with the added wording “Galvanostatic tests at 1 and 3 mA cm–2 can be found in Supplementary Fig. 19.”