Search Results (10)

Phase molybdenum disulfide (1T-MoS₂) holds significant promise as an anode material for sodium-ion batteries (SIBs) due to its metallic conductivity and expanded interlayer distance. However, the practical application of 1T-MoS₂ is hindered by its inherent thermodynamic metastability, which poses substantial challenges for the synthesis of high-purity, long-term stable 1T phase MoS₂. Herein, a synergetic ethanol molecule intercalation and electron injection engineering is adopted to induce the formation and stabilization of 1T-MoS₂ (E-1T MoS₂). The obtained E-1T MoS₂ consists of regularly arranged sphere-like ultrasmall few-layered 1T-MoS₂ nanosheets with expanded interlayer spacing. The high intrinsic conductivity and enlarged interlayer spacing are greatly favorable for rapid Na⁺ or e⁻ transport. The elaborated nanosheets structure can effectively relieve volume variation during Na⁺ intercalating/deintercalating processes, shorten transport path of Na⁺, and enhance diffusion kinetics. Furthermore, a novel sodium reaction mechanism involving the formation of MoS₂ nanoclusters during cycling is revealed to produce the higher surface pseudocapacitive contribution to Na⁺ storage capacity, accelerating Na⁺ reaction kinetics, as confirmed by the kinetics analysis and ex-situ structural characterizations. Consequently, the E-1T MoS₂ electrode exhibits an excellent sodium storage performance. This work provides an important reference for synthesis and reaction mechanism analysis of metastable metal sulfides for advanced SIBs. Full article

It is found that Mo doping can enhance the supercapacitor performance of VS₂ microflowers. The X-ray diffraction combined with energy dispersive X-ray, X-ray photoelectron spectroscopy, and Raman spectra results verify the successful doping of Mo atoms into the VS₂ matrix. As the electrode material of supercapacitors, the Mo-doped VS₂ performs better electrochemical performance than pristine VS₂, achieving the specific capacitance of 170 F g⁻¹ at 0.5 A g⁻¹ and 389.5 F g⁻¹ at 5 mV s⁻¹. Furthermore, the symmetric supercapacitor based on the Mo-doped VS₂ exhibits good stability and ideal rate capability. The enhanced capability is presumably ascribed to the more accessible active sites and faster electrons/ions diffusion kinetics, which are caused by the increased specific surface area, expanded interlayer spacing, and improved conductivity after Mo doping. This strategy can also be extended to strengthen the capacitive properties of other transition metal dichalcogenides for advanced energy storage devices. Full article

Aqueous zinc-ion batteries (ZIBs) represent an emerging energy storage solution that offers significant advantages in terms of safety, cost-effectiveness, and longevity in cycling. Among the various materials available, manganese-based oxides stand out as the most promising options for cathodes due to their impressive theoretical specific capacity, suitable operating voltage, and abundant natural availability. In published reports, pre-embedding is frequently used to modify the layered cathode; however, non-electrochemically active molecular embedding often results in a decrease in battery capacity. In this paper, a hydrothermal method is employed to intercalate poly(o-phenylenediamine) (PoPD) into δ-MnO₂ (MO) to produce PoPD-MO cathode materials. Here, PoPD serves a dual role in the cathode: (1) PoPD is inserted into the interlayer of MO, providing support within the intercalation layer, enhancing material stability, increasing ionic storage sites, and creating space for more Zn²⁺ to be embedded, and (2) inserting PoPD into the interlayer structure of MO effectively expands the space between layers, thus allowing for greater ion storage, which in turn enhances the rate and efficiency of electrochemical reactions. Consequently, PoPD-MO shows remarkable cycling durability and adaptability in ZIBs, achieving a specific capacity of 359 mAh g⁻¹ at a current density of 0.1 A g⁻¹, and even under the strain of a high current density of 3 A g⁻¹, it maintains a respectable capacity of 107 mAh g⁻¹. Based on this, PoPD-MO may emerge as a new cathode material with promising applications in the future. Full article

Lithium–sulfur (Li-S) batteries offer a high theoretical energy density but suffer from poor cycling stability and polysulfide shuttling, which limits their practical application. To address these challenges, we developed a PANI-modified MoS₂-NG composite, where MoS₂ nanoflowers were uniformly grown on graphene oxide (GO) through PANI modification, resulting in an increased interlayer spacing of MoS₂. This expanded spacing exposed more active sites, enhancing polysulfide adsorption and catalytic conversion. The composite was used to prepare MoS₂-NG/PP separators for Li-S batteries, which achieved a high specific capacity of 714 mAh g⁻¹ at a 3 C rate and maintained a low capacity decay rate of 0.085% per cycle after 500 cycles at 0.5 C. The larger MoS₂ interlayer spacing was key to improving redox reaction kinetics and suppressing the shuttle effect, making the MoS₂-NG composite a promising material for enhancing the performance and stability of Li-S batteries. Full article

Structural unsteadiness and sluggish diffusion of divalent zinc cations in cathodes during cycling severely limit further applications of MoS₂ for rechargeable aqueous zinc-ion batteries (ZIBs). To circumvent these hurdles, herein, phosphorus (P) atom embedded three-dimensional marigold-shaped 1T MoS₂ structures combined with the design of S vacancies (Sv) are synthesized via the oxygen-assisted solvent heat method. The oxygen-assisted method is utilized to aid the P-embedding into the MoS₂ crystal, which can expand the interlayer spacing of P-MoS₂ and strengthen Zn²⁺ intercalation/deintercalation. Meanwhile, the three-dimensional marigold-shaped structure with 1T phase retains the internal free space, can adapt to the volume change during charge and discharge, and improve the overall conductivity. Moreover, Sv is not only conducive to the formation of rich active sites to diffuse electrons and Zn²⁺ but also improves the storage capacity of Zn²⁺. The electrochemical results show that P-MoS₂ can reach a high specific capacity of 249 mAh g⁻¹ at 0.1 A g⁻¹. The capacity remains at 102 mAh g⁻¹ after 3260 cycles at a current of 0.5 A g⁻¹, showing excellent electrochemical performance for Zn²⁺ ion storage. This research provides a more efficient method of P atom embedded MoS₂-based electrodes and will heighten our comprehension of developing cathodes for the ZIBs. Full article

Potassium-ion batteries (PIBs) have aroused a large amount of interest recently due to the plentiful potassium resource, which may show cost benefits over lithium-ion batteries (LIBs). However, the huge volume expansion induced by the intercalation of large-sized potassium ions and the intrinsic sluggish kinetics of the anode hamper the application of PIBs. Herein, by rational design, nano-roses assembled from petals with a MoS₂/monolayer carbon (C-MoS₂) sandwiched structure were successfully synthesized. The interlayer distance of ultrathin C-MoS₂ was expanded from original MoS₂ of 6.2 to 9.6 Å due to the formation of the MoS₂-carbon inter overlapped superstructure. This unique structure efficiently alleviates the mechanical strain, prevents the aggregation of MoS₂, creates more active sites, facilitates electron transport, and enhances the specific capacity and K⁺ diffusion kinetics. As a result, the prepared C-MoS₂-1 anode delivers a high reversible specific capacity (437 mAh g⁻¹ at 0.1 A g⁻¹) and satisfying rate performance (123 mAh g⁻¹ at 6.4 A g⁻¹). Therefore, this work provides new insights into the design of high-performance anode materials of PIBs. Full article

All-solid-state batteries (SSBs) are prospective candidates for a range of energy accumulation systems, delivering higher energy densities compared to batteries which use liquid electrolytes. Amongst the numerous solid-state electrolytes (SEs), sulfide-based electrolytes in particular have received more attention given that they have a high ionic conductivity. However, the incompatibility between the electrode and SEs is still an ongoing challenge that leads to poor electrochemical performance. In this work, we focus on 1T-MoS₂. It is well known that 1T metallic MoS₂ is unstable even at room temperature. However, we showed that 1T-MoS₂ can be stabilized at 600 °C for at least 2 h, and the 1T-MoS₂-600 interlayer spacing expanded to 0.95 nm. The high crystallinity of the 1T phase is highly compatible with solid electrolytes and coupled with the increased interlayer spacing, so in the all-solid-state lithium-ion battery (ALLLIB), we achieved outstanding cycling performance. At the current density of 0.2 C (1 C = 670 mA g⁻¹), this material delivered a capacity of 406 mA h g⁻¹ after 50 cycles. Full article

Molybdenum disulfide (MoS₂) has been universally demonstrated to be an effective electrocatalytic catalyst for hydrogen evolution reaction (HER). However, the low conductivity, few active sites and poor stability of MoS₂-based electrocatalysts hinder its hydrogen evolution performance in a wide pH range. The introduction of other metal phases and carbon materials can create rich interfaces and defects to enhance the activity and stability of the catalyst. Herein, a new defect-rich heterogeneous ternary nanocomposite consisted of MoS₂, NiS and reduced graphene oxide (rGO) are synthesized using ultrathin αNi(OH)₂ nanowires as the nickel source. The MoS₂/rGO/NiS-5 of optimal formulation in 0.5 M H₂SO₄, 1.0 M KOH and 1.0 M PBS only requires 152, 169 and 209 mV of overpotential to achieve a current density of 10 mA cm⁻² (denoted as η₁₀), respectively. The excellent HER performance of the MoS₂/rGO/NiS-5 electrocatalyst can be ascribed to the synergistic effect of abundant heterogeneous interfaces in MoS₂/rGO/NiS, expanded interlayer spacings, and the addition of high conductivity graphene oxide. The method reported here can provide a new idea for catalyst with Ni-Mo heterojunction, pH-universal and inexpensive hydrogen evolution reaction electrocatalyst. Full article

Molybdenum disulfide (MoS₂) has attracted considerable attention as a promising electrocatalyst for the hydrogen evolution reaction (HER). However, the catalytic HER performance of MoS₂ is significantly limited by the few active sites and low electrical conductivity. In this study, the growth of multiorientated polycrystalline MoS₂ using plasma-enhanced chemical vapor deposition (PECVD) for the HER is achieved. The MoS₂ is synthesized by sulfurizing a sputtered pillar-shaped Mo film. The relatively low growth temperature during the PECVD process results in multiorientated MoS₂ with an expanded interlayer spacing of ~0.75 nm, which provides abundant active sites, a reduced Gibbs free energy of H adsorption, and enhanced intralayer conductivity. In HER applications, the PECVD-grown MoS₂ exhibits an overpotential value of 0.45 V, a Tafel slope of 76 mV dec⁻¹, and excellent stability in strong acidic media for 10 h. The high HER performance achieved in this study indicates that two-dimensional MoS₂ has potential as an electrocatalyst for next-generation energy technologies. Full article

Nano-structured molybdenum disulfide (MoS₂) catalysts have been extensively developed for the hydrogen evolution reaction (HER). Herein, a novel hydrothermal intercalation approach is employed to fabricate nanoflower-like 2H–MoS₂ with the incorporation of three polymers, polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), and polyethylenimine (PEI). The as-prepared MoS₂ specimens were characterized by techniques of scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), together with Raman and Fourier transform infrared spectroscopy (FTIR). The HER properties of these lamellar nanoflower-like composites were evaluated using electrochemical tests of linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The existent polymer enlarges the interlayer spacing of the lamellar MoS₂, and reduces its stacked thickness. The lamellar MoS₂ samples exhibit a promoting activity in HER at low additions of these three polymers (0.04 g/g MoS₂ for PVA and PEI, and 0.08 g/g MoS₂ for PVP). This can be attributed to the fact that the expanded interlayer of MoS₂ can offer abundant exposed active sites for HER. Conversely, high additions of the polymers exert an obvious interference in the HER activity of the lamellar MoS₂. Compared with the samples of MoS₂/PVP–0.08 and MoS₂/PEI–0.04, the MoS₂/PVA–0.04 composite exhibits excellent activity in HER, in terms of higher current density and lower onset potential. Full article