MoS2 Carbon Research Articles

Piezoelectric performance of monolayer molybdenum disulfide carbon nanogenerator

Smart sensing devices with high reliability and self-powering features are critical for future-generation wearable applications. In this study, a MoS2–carbon nanofiber (CNF) piezoelectric nanogenerator (PENG) was fabricated using MoS2 nanocrystals. The fabricated MoS2–CNFs device was used as a sensor for harvesting diverse deformation energies, demonstrating its high potential as an actuating and sensing material. The microstructure and morphology of the MoS2–CNFs were examined via X-ray diffraction, Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). These investigations confirmed the successful synthesis of monolayer MoS2 nanocrystalline structure with a size of 6 nm and uniform distribution. Further, the presence of monolayer MoS2 nanocrystalline structure enhanced the conductivity of CNFs, thereby improving its self-powering functionality and piezoelectric properties. The MoS2–CNFs composite achieved a maximum output voltage amplitude of 850 mV under applied bending deformation. This research offers a new approach for developing piezoelectric nanofibrous devices and energy-harvesting systems.

Mini-Review on Conducting Polymer–MoS2–Carbon Ternary Composite as a Hybrid Electrode Material for Supercapacitor Applications: Progress and Perspectives

Supercapacitors have drawn a lot of interest as a result of recent significant improvements in electronic devices to address the growing energy dilemma. In stoichiometric combinations of materials, the hybrid strategy of mixing an EDLC with a pseudocapacitive material can produce noticeable specific capacitance, energy, and power density with strong cycle stability. Research into developing more advanced hybrid materials finds a bright future based on the broad variety of applications in numerous power-related technologies. This brief overview summarizes recent advancements in research and technology pertaining to conducting polymer–MoS2–carbon ternary hybrid composite supercapacitors, their architectural design, and their performances.

MoS2—Carbon Materials Composite with Dual Phase of MoS2 and Their Application for Anode of Lithium Ion Battery

Carbon materials such as graphite, graphene, and CNT are mainly used as anode materials for LIBs because of their wide surface area and excellent stability in Lithium Ion Battery operation. However, graphite, which is mainly used as an anode material, has a very low theoretical capacity of 372 mAh/g. As high-capacity LIBs are increasingly needed like electric vehicles, many studies are being conducted to increase LIB capacity. For example, research on Si anode materials is attracting attention, and Si has a high theoretical capacity of ~4200 mAh/g. However, since there is a fatal disadvantage of volume expansion in cycle performance, stability can be a major defect in the driving condition of LIB.Transition Metal Dichalgogenides (TMD) materials are attraction a lot of attention as various energy materials such as HER and ORR as well as LIB. Their structural characteristics, low price, and high capacity in terms of energy storage make them very attractive to study as a new anode material for LIB batteries. MoS2 belonging to the TMD material is known to have a theoretical capacity of 670 mAh/g. In particular, MoS2 has a single layer structure, and this single layer structure is coupled by weak van der walls force. These properties are very advantageous for exfoliating MoS2 to form a layer-by-layer form with other materials. MoS2 is known to have a typical 1T, 2H structure. However, MoS2, which exists in a stable phase, generally has a 2H structure and has semiconducting properties. Therefore, it is less conductive than graphene, which can be an obstacle to being used as an anode. MoS2 is known to have a typical 1T, 2H structure. However, MoS2, which exists in a stable phase, generally has a 2H structure and has semiconducting properties. Therefore, it is less conductive than graphene, which can be an obstacle to being used as an anode. 1T structure is known to have very good conductivity because it has conductive properties. Therefore, when used as an anode, it has many advantages in that it has conductivity, but since it is a metastable structure, it can be converted to 2H very easily, so it is not easy to maintain the structure.In this study, the synthesis of MoS2 and graphene composites was performed in one pot using a chemical exfoliation method. In addition, it was possible to stably maintain the metastable 1T structure of MoS2 by using graphene as a support material through a post-treatment process in this process. The diffusion of Li+ was promoted by having a 1T structure with a wide interfacial spacing and high conductivity, and superior conductivity and high capacity were stably maintained compared to a composite having a 2H single phase. Through this, a stable and high-capacity anode material was realized using the high energy storage capacity of MoS2 and the stability of graphene.

MoS2/C nanotubes synthesized using halloysite as template through one-pot hydrothermal method for Li-ion batteries

One-dimension MoS2/carbon (MoS2/C) with expended interlayer spacing of MoS2 has been proposed as a promising strategy to improve the electrochemical performance of MoS2 materials in lithium-ion batteries (LIBs). Surface etched or functionalized carbon nanotubes/fibers are usually used as carriers or hosts for MoS2/C in preparing 1 D MoS2/C materials. However, the widespread adoption is hindered by the expensive carbon nanotubes/fibers and the tedious preparation process. Herein, low-cost natural halloysite was introduced as a template in synthesizing MoS2/C nanotube (NT-MoS2/C) with expended interlayer spacing through one-pot hydrothermal method. The tubular structure, larger specific surface area (43.81 m2/g) and larger mesopore volume (0.16 cm3 g−1, Vmes/Vtotal = 72.45 %) of NT-MoS2/C have been obtained with halloysite as template compared to NP-MoS2/C (without using halloysite as template) and NC-H@MoS2/C (without removal of halloysite template). When used as lithium storage electrodes, the rate performance and cycling stability of NT-MoS2/C have been significantly improved over NP-MoS2/C and NC-H@MoS2/C by the constructed tubular structure. The lithium storage electrochemical performance of MoS2/C with expended interlayer spacing can be further improved by tubular structure constructed with natural halloysite as template. This strategy is expected to offer a pathway towards the scalable application of MoS2/C materials in next-generation LIBs technology.

High-efficiency cycling piezo-degradation of organic pollutants over three liters using MoS2/carbon fiber piezocatalytic filter

Piezocatalysis has great potential commercial application for the high-efficiency degradation of organic pollutants in a dark environment. However, the recycling of catalyst materials and the subsequent generation of secondary pollution remain challenging. In this study, MoS2 nanoflowers (NFs)/carbon fiber was synthesized to develop a piezocatalytic filter that can recycle decomposed wastewater easily without generating secondary pollutants in treated water. The MoS2/carbon fiber was constructed in pipelines to form the piezoelectric degradation system, which demonstrated a high efficiency in decomposing organic molecules in wastewater through natural water flow. The piezocatalytic filters in the circulatory system completely degraded a large amount of dye solution (1000 mL) in 40 min and can repeat three-times degradation with the total organic carbon value decreased by 90%. The theoretical calculation indicated that MoS2 grew on carbon fiber, which exhibited a bending moment effect under natural water-flow-induced pressure. This established considerable piezoelectric potential at MoS2 NFs active edge sites and MoS2–carbon fiber interfaces, triggering electron–hole pair separation under the internal electric field. The MoS2/carbon fiber piezoelectric catalyst is advantageous for its reusability and recyclability, thus preventing secondary pollution and adverse effects on water bodies during practical high-flux wastewater treatment.

MXene-Bonded hollow MoS2/Carbon sphere strategy for high-performance flexible sodium ion storage

Sodium-ion batteries, as a promising alternative to the lithium-ion battery, have attracted extensive attention. However, due to the larger ion radius and higher standard reduction potential, the sodium-ion batteries still face poor cycle stability and relatively low energy density problems. In this work, a carbon sphere-supported Nb2CTx MXene/MoS2 hierarchical structure has been designed and synthesized through hydrothermal and electrostatic self-assembly methods. The design strategy successfully improves the utilization efficiency of the MoS2 carbon sphere as a support skeleton and reducing the diffusion path length of Na ions, leading to an improved specific capacity and rate performance. Moreover, Nb2CTx sheets also effectively inhibit the capacity attenuation caused by MoS2 shedding, thus achieving the long cycle life of the sodium-ion battery. As a result, the carbon-supported MXene/MoS2 anode delivers an ultrahigh reversible capacity, long cycling stability, and superior capacity retention rate. Notably, the carbon-supported MXene/MoS2 anode can also obtain a considerable capacity of 196 mAh g−1 at a current density of 20 A g−1. The full cell of SIBs was assembled, and the flexibility of the battery was tested. The density functional theory simulation results show that the sodium ion has a smaller diffusion barrier under this material design strategy.

Frontispiece: Covalently Aligned Molybdenum Disulfide–Carbon Nanotubes Heteroarchitecture for High‐Performance Electrochemical Capacitors

Energy Storage In their Research Article on page 21295, Guan Wu, Jianhong Xu, Ningzhong Bao et al. report a covalently aligned MoS2–carbon nanotube architecture for high-performance electrochemical capacitors.

Carbonaceous-MoS2 nanoflower-based counter electrodes for bifacial dye-sensitized solar cells

MoS2-based transition metal dichalcogenide nanoflowers are synthesized using the hydrothermal method and their potential as a counter electrode in dye-sensitized solar cells (DSSCs) is examined. Structural analysis of synthesized MoS2 is analysed using x-ray diffraction spectra and Raman spectroscopy. The morphology and microstructural properties are investigated using field-emission scanning electron microscopy and high-resolution transmission electron microscopy, respectively. DSSCs are fabricated using different counter electrodes (MoS2, MoS2-carbon black and MoS2-high conductive carbon paste (HCP)), which are deposited using a simple spin-coating method and annealed at a temperature of 80 °C. The electrochemical properties of the fabricated counter electrodes are studied using electrochemical impedance spectroscopy. Among the different counter electrodes, MoS2–HCP shows better electrochemical performance. The high electrocatalytic and conducting nature of the MoS2–HCP-based counter electrode produces 5% power conversion efficiency, which is comparable to expensive Pt-based counter electrodes (5.4%). To demonstrate the bifacial concept of DSSC, 2.2% power conversion efficiency is attained with rear-side illumination under one sun (100 mW cm−2, AM 1.5 G).

Engineering metallic MoS2 monolayers with responsive hydrogen evolution electrocatalytic activities for enzymatic reaction monitoring

Metallic and defect-rich MoS2 monolayers are prepared via a Schlenk line, exhibiting ROS-responsive performance. Engineered MoS2 carbon fibers are integrated with an enzymatic reaction, illustrating the practical applications of the HER-based electroanalysis.

Spherical MoS2/Carbon Composite with Improved Electrochemical Performance for Sodium-Ion Battery Anode

Lithium-ion batteries (LIBs) with high energy density and long cycle life have been widely applied as the power sources in a variety of fields from portable electronic devices to large-scale energy storage systems (ESSs). Particularly in recent years, owing to the rapid growth of global electric vehicle and ESS markets, the cost of lithium source has risen sharply and many researchers predict a lithium shortage in the near future. In this regard, sodium-ion batteries (SIBs) have recently attracted growing attention because of low price and huge natural abundance of sodium, compared to lithium. However, the larger ionic radius of sodium ion (1.02 Å) than that of lithium (0.76 Å) results in poor electrochemical behaviors, which makes it difficult to find suitable anode materials for SIBs. [1] Among many proposed anode materials for SIBs, molybdenum disulfide (MoS2) is one of promising sodium-ion host materials because of its 2D-layered structure and high theoretical capacity of 670 mA h g-1. Despite these advantages, when used as an anode for SIBs, MoS2 exhibits several problems associated with low cycling stability and poor rate performance caused by large volume change during sodium insertion and extraction and low electrical conductivity. [2] In order to solve the aforementioned drawbacks of MoS2, herein, we present a spherical-shaped MoS2/carbon (MoS2/C) composite as a high-performance anode for SIBs. The spherical MoS2/C composites were synthesized by a facile and simple in situ wet chemical method using furfural as a surfactant as well as a carbon source. The as-prepared MoS2/C composite showed uniform distribution of MoS2 particles in the mesoporous carbonaceous matrix, which not only effectively alleviates large volume variation during repeated cycling, but also ensures high electrical conductivity. Owing to these benefits of good dispersion of active materials and the introduction of multifunctional matrix, the spherical MoS2/C composite electrodes demonstrated improved electrochemical performance such as enhanced cycle stability and superior rate capability. Furthermore, we believe that our facile and effective approach to synthesize MoS2/C composites can be extended to design and develop various transition metal-chalcogenides as promising and desirable anode candidates for SIBs.REFERENCE[1] Y. Xiao, S. H. Lee, Y. K. Sun, Adv. Energy Mater. 2017, 7, 1601329[2] Q. Pan, Q. Zhang, F. Zheng, Y. Liu, Y. Li, X. Ou, X. Xiong, C. Yang, M. Liu, ACS Nano 2018, 12, 12578. Figure 1

Rational Design of Hierarchical TiO2/Epitaxially Aligned MoS2–Carbon Coupled Interface Nanosheets Core/Shell Architecture for Ultrastable Sodium‐Ion and Lithium–Sulfur Batteries

AbstractThe development of electrode materials with superior cycling stability is currently receiving intensive research for next‐generation portable electronic equipment. Herein, a novel 3D hierarchical architecture composed of TiO2/epitaxially aligned MoS2–carbon coupled interface nanosheets is reported for boosting sodium‐ion storage and lithium–sulfur batteries, in which the MoS2 nanosheets are epitaxially aligned grown on the surface of carbon nanosheets through a simple calculation conversion process. The resulting hybrid demonstrates ultralong‐life performance for sodium‐ion storage and lithium–sulfur batteries, owing to synergistic effects among the stable TiO2 nanowires, the high‐conductivity carbon nanosheets, and the vertical MoS2 nanostructure. Even at a high current density of 8 A g−1, the capacity can be maintained at 169 mA h g−1 after 15 000 cycles, one of the highest values for TiO2‐based electrodes. Moreover, such peculiar sheet‐on‐sheet structure also brings benefits for lithium–sulfur batteries, providing an effective physical shield against polysulfide shuttling and chemical adsorption of polysulfides, with a low fading rate (0.039% per cycle over 1500 cycles). The present work highlights that this rationally designed hybrid nanoarchitecture is an effective strategy to boost the stability of electrochemical energy storage.

Sodium storage in a promising MoS2-carbon anode: elucidating structural and interfacial transitions in the intercalation process and conversion reactions.

Sodium-ion batteries and capacitors are considered as low-cost energy storage devices, compared to Li-ion counterparts. However, most anodes for sodium-ion devices show sluggish kinetics and poor structural stability caused by the large radius (1.02 Å) of Na+. One candidate anode is MoS2, a 2D atomic layered material with a large interlayer spacing of 6.2 Å, that can take up and release Na+via two working principles: a two-electron intercalation process and a four-electron conversion reaction. Herein, we report a facile method to synthesize a MoS2-amorphous carbon (MoS2-AC) nanocomposite and further study the effect of the two working principles on the structure, interphase, and charge storage properties of MoS2-AC. The two-electron intercalation reaction enables the MoS2-AC electrode to have a higher rate capability and superior stability than that via the four-electron Na+ conversion reaction. This favorable Na+ charge storage performance of MoS2-AC via the two-electron intercalation process is attributed to its pseudocapacitive behavior, a stable solid electrolyte interphase and robust stability of the structure, which enables us to fabricate a sodium-ion capacitor that can deliver high energy density at a high rate. This work underscores the potential importance of realizing fast Na+ charge storage via an intercalation process as a strategy for the fabrication of high-performance sodium-ion capacitors and batteries.

2D MoS2–carbon quantum dot hybrid based large area, flexible UV–vis–NIR photodetector on paper substrate

While all reports on 2D–0D hybrid photodetectors are on silicon substrate and based on heavy metals quantum dots exhibiting limited range detection, this paper is the first demonstration of 2D MoS2–carbon quantum dot (CQD) based flexible broadband photodetector (PD) wherein MoS2 was grown on cellulose paper using hydrothermal method and CQD was synthesized using a low cost, one step pyrolytic process of chia seeds. The absorbance of CQD in UV region combined with the broadband absorption of MoS2 in visible and NIR region broadens the absorbance range. Structural characterization revealed few layered MoS2 and CQD to be in the range of 2–6nm. Responsivity for the fabricated sensor was found to be 8.4, 2.62 and 18.12mA/W in UV, NIR and visible region respectively which are comparable and even better compared to photodetector fabricated using sophisticated cleanroom techniques. The PD showed negligible variation in photoresponse under repeated (up to 500 cycles) bending conditions. Discrete distribution of CQD over MoS2 creates unipolar junctions which helps in generation of small local electric fields thereby increasing the sensitivity of the sensor. The work presented here is a major step ahead in fabrication of low-cost flexible broadband photodetectors which finds potential applications in the field of flexible and wearable electronics, security and surveillance systems, etc.

Elucidating the Intercalation Pseudocapacitance Mechanism of MoS2-Carbon Monolayer Interoverlapped Superstructure: Toward High-Performance Sodium-Ion-Based Hybrid Supercapacitor.

Two-dimensional (2D) layered materials have shown great promise for electrochemical energy storage applications. However, they are usually limited by the sluggish kinetics and poor cycling stability. Interface modification on 2D layered materials provides an effective way for increasing the active sites, improving the electronic conductivity, and enhancing the structure stability so that it can potentially solve the major issues on fabricating energy storage devices with high performance. Herein, we synthesize a novel MoS2-carbon (MoS2-C) monolayer interoverlapped superstructure via a facile interface-modification route. This interlayer overlapped structure is demonstrated to have a wide sodium-ion intercalation/deintercalation voltage range of 0.4-3.0 V and the typical pseudocapacitive characteristics in fast kinetics, high reversibility, and robust structural stability, thus displaying a large reversible capacity, a high rate capability, and an improved cyclability. A full cell of sodium-ion hybrid supercapacitor based on this MoS2-C hybrid architecture can operate up to 3.8 V and deliver a high energy density of 111.4 Wh kg-1 and a high power density exceeding 12 000 W kg-1. Furthermore, a long cycle life of 10 000 cycles with over 77.3% of capacitance retention can be achieved.

One-pot synthesis of multifunctional magnetic ferrite–MoS2–carbon dot nanohybrid adsorbent for efficient Pb(ii) removal

Multifunctional MFe2O4 (M = Mn, Co)–MoS2–carbon dot nanohybrid composites were fabricated using a one-pot solvothermal method and applied for efficient Pb(ii) removal.

2D Monolayer MoS₂-Carbon Interoverlapped Superstructure: Engineering Ideal Atomic Interface for Lithium Ion Storage.

A novel strategy for the controlled synthesis of 2D MoS2/C hybrid nanosheets consisting of the alternative layer-by-layer interoverlapped single-layer MoS2 and mesoporous carbon (m-C) is demonstrated. Such special hybrid nanosheets with a maximized MoS2 /m-C interface contact show very good performance for lithium-ion batteries in terms of high reversible capacity, excellent rate capability, and outstanding cycling stability.

The dopamine-Mo(VI) complexation-assisted large-scale aqueous synthesis of a single-layer MoS₂/carbon sandwich structure for ultrafast, long-life lithium-ion batteries.

Single-layer MoS2-carbon nanocomposites (SLMoS2/C) are facilely prepared via a dopamine (DOPA)-Mo(VI) complexation-assisted approach. The large interlayer spacing, sandwich structure and crumpled nanosheet morphology of SLMoS2/C render it excellent electrochemical performances as a lithium-ion battery anode, showing a reversible capacity of 500 mA h g(-1) at a discharge rate of 5 A g(-1).

Self-assembled MoS2–carbon nanostructures: influence of nanostructuring and carbon on lithium battery performance

Composites of MoS2 and amorphous carbon are grown and self-assembled into hierarchical nanostructures via a hydrothermal method. Application of the composites as high-energy electrodes for rechargeable lithium-ion batteries is investigated. The critical roles of nanostructuring of MoS2 and carbon composition on lithium-ion battery performance are highlighted.