Unique Layered Structure Research Articles

An ultrasensitive electrochemical sensor based on antimonene simultaneously detect multiple heavy metal ions in food samples.

Here, we constructed a novel ultra-sensitive electrochemical sensor based on ZIF-67@antimonene (AMNFs) nanocomposites which are based on the first-principles density functional theory the adsorption properties of antimonene on heavy metal ions were studied for simultaneous determination of Cu2+, Pb2+ and Hg2+. The ZIF-67@AMNFs was prepared by using ZIF-67 MOF surface loaded with a large amount of antimonene sheet. Its morphology and crystal structure were characterized by Transmission electron microscope (TEM), Energy Dispersive Spectroscopy (EDS), X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). Functional ZIF-67@AMNFs due to its unique layered structure, large active surface area, strong adsorption capacity and good electrical conductivity. In addition, the adsorption capacity of the sensor electrode for Cu2+, Pb2+ and Hg2+ was effectively enhanced. The detection limits of Cu2+, Pb2+ and Hg2+ were 0.01pM, 0.042pM and 0.031pM, respectively. The determination mechanism of Cu2+, Pb2+ and Hg2+ was further clarified based on the adsorption properties and electrochemical accumulation of antimonene on metal atoms. It has been successfully applied to the simultaneous determination of Cu2+, Pb2+ and Hg2+ in rice, sorghum, corn, milk, honey and tea samples, and has good practicability.

Mechanistic insights into the deprotonation of methanol by facile synthesized 3D flower-like BiOX (X= Cl, Br, I) catalysts for rapid hydrogen generation from NaBH4 methanolysis: The ‘X’ factor

Bismuth oxyhalides (BiOX, X = Cl, Br, I) have been showing promising catalytic activity in various applications due to their electronic properties and unique layered structure. However, their catalytic potential for hydrogen generation from chemical hydrides is unrevealed. Herein, BiOX (X = Cl, Br, I) catalysts were prepared via a simple co-precipitation method. The physical and chemical characteristics of the as-prepared samples were then duly characterized using various techniques such as X-ray diffractometer spectroscopy (XRD), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Nitrogen adsorption-desorption, and Scanning electron microscope (SEM). The catalysts were then applied to NaBH4 methanolysis for the production of hydrogen. Among the BiOX catalysts, BiOCl exhibits excellent performance which is attributed to the highest electronegativity possessed by the Cl− halogens clinging onto the catalytic layers, simply overriding the substitution reactions. Subsequently, superior performances were depicted with rapid generation of hydrogen, High rate of hydrogen generation, HGR = 42,740 mL H2 g−1min−1, and calculated activation energy of Ea = 43.5 kJ/mol with stability for over 5 successive cycles. Withal, a plausible mechanism based on the exchange reactions promoted by the BiOX catalysts, which comprises interlacing [Bi2O2] slabs with double halogen slabs coupled with a strong ionic nature is illustrated in line with the experimental results.

Anammox granule destruction and reconstruction in a partial nitrification/anammox system under hydroxylamine stress

Nitrite oxidizing bacteria (NOB) outcompeting anammox bacteria (AnAOB) poses a challenge to the practical implementation of the partial nitrification/anammox (PN/A) process for municipal wastewater. A granules-based PN/A bioreactor was operated for 260 d with hydroxylamine (NH2OH) added halfway through. qPCR results detected the different amounts of NOB among granules and flocs and the dynamic succession during operation. CLSM images revealed a unique layered structure of granules that NOB located inside led to the inhibition effect of NH2OH delayed. Besides, the physical and morphological characteristics revealed that anammox granules experienced destruction. AnAOB took the broken granules as an initial biofilm aggregate to reconstruct new granules. RT-qPCR and high throughput sequencing results suggested that functional gene expression and community structure were regulated for the AnAOB metabolism process. Correspondingly, the rapid proliferation (0.52 → 1.99%) of AnAOB was realized, and the nitrogen removal rate achieved a nearly quadruple improvement (0.21 → 0.83 kg-N/m3·d). This study revealed that anammox granules can self-reconstruct in the PN/A system when granules are disintegrated under NH2OH stress, broadening the feasibility of applying PN/A process.

Discovery of new MAX-phase-like layered ternary carbide V8P6C: Crystal structure, thermal expansion, and elastic properties

Due to the laminated structure, MAX phases and MAX-phase-like compounds possess outstanding damage tolerance capability with good thermal/electrical conductivity and other charming functional properties, showing a bright future for structural-functional uses. Here, a new MAX-phase-like ternary carbide V8P6C with layered characteristics was discovered. Contrary to the alternate stacking of hexagonal-arranged M/A/X atom layers in MAX phases, V8P6C has a layered structure formed by a repeated stacking of the slabs consisting of V6C-octahedrons and VP6-distorted-octahedrons in three-atomic layers thick. The thermal expansion anisotropy was revealed, with the thermal expansion coefficients (TECs) along a-axis, c-axis, and the average value, equal to αa=8.55(5) μK−1, αc=10.23(5) μK−1, and αL=9.14(5) μK−1, respectively. The dilation along the c-axis was mainly dominated by out-plane V-P bonds between layered slabs. According to the pressure-dependent lattice parameters, the polycrystalline bulk modulus (B0 = 185(9) GPa) and high compressibility anisotropy factor (Ba/Bc = 1.64) was found. Meanwhile, the second-order elastic constants were calculated, and the elastic moduli, E=303 GPa, B=198 GPa, G=122 GPa, and ν = 0.246, were obtained. And the weak connection between layer slabs by out-plane V1-P bond was revealed by the bond stiffness model, with a bond stiffness close to the M-A bond in MAX phases. Furthermore, good damage tolerance capability was predicted according to Paugh's ratio (G/B=0.616) and Cauchy pressure (Pa = 0 GPa, Pc = -7.5 GPa), even better than those of typical MAX phases. The discovery of V8P6C provides a new member of MAX-phase-like damage-tolerant ceramic with relatively low density, moderate thermal expansion, and anisotropic compressibility, and the unique layered structure is inspiring for exploring new layered ternary ceramics.

PH-responsive magnetic graphene oxide composite as an adsorbent with high affinity for rapid capture of nucleosides.

Anovel pH-responsive magnetic graphene oxide composite (MGO@PEI-BA) isproposed for the first time as an adsorbent for the rapid capture and detection of nucleosides (cytidine, uridine, guanosine, and adenosine). The morphology, structure, and magnetic properties of thecomposite were evaluated using various characterization techniques. The results indicated that the composite was successfully fabricated. A series of parameters that affect extraction and elution were optimized through one-factor-at-a-time and Box-Behnken design of response surface methodology (BBD-RSM). The unique layered structures and easily accessible active sites of the composite facilitated molecular transport, resulting in instantaneous equilibrium of nucleosides adsorption within 5 min. Based on this study, a magnetic dispersive micro-solid-phase extraction (MD-μ-SPE) method assisted by the MGO@PEI-BA was developed in combination with UHPLC-UV analysis for the determination of nucleosides in rat urine. Under the optimum conditions, a wide linear range (10-2000 ng mL-1), good linearity (r > 0.99), low detection limits (1-3 ng mL-1), low relative standard deviations (RSDs ≤ 3.9%), and satisfactory recoveries (82.7-96.3%) were achieved. These results demonstrate that the MGO@PEI-BA is an excellent adsorbent for extracting nucleosides from biological samples.

Graphene oxide-coated Ag-TiO2 hybrid nanocomposites for superior photocatalytic activity.

Graphene oxide (GO) has now emerged as one of the most promising materials in different areas such as photocatalysis, adsorption, and energy storage due to its high surface area, unique layered structure, etc. Among various types of precursors, anthracite coal has attracted a lot of attention nowadays as it affords GO a high concentration of sp2 carbons resulting in high conductivity and superior absorbance in the visible region. In this report, we have prepared GO-TiO2 nanocomposites as it is supposed to possess high photocatalytic activity owing to facile electron transmission from the conduction band of TiO2 to the GO surface resulting in a much lower degree of electron-hole pair recombination. To boost the photocatalytic activity further, TiO2 was coated with Ag nanoparticles as well. These hybrid structures were characterized by different analytical techniques, for example, XRD, HR-TEM, SEM, and Raman spectroscopy. The XRD pattern of these composites consists of characteristic peaks corresponding to GO, TiO2, and Ag. The HR-TEM studies confirm the presence of GO layers, cube-shaped TiO2, and spherical Ag nanoparticles. Phenol and 4-nitrophenol have been used as model pollutants to evaluate the photooxidation efficiencies under both UV and visible light irradiation. Under UV irradiation, the GO/Ag-TiO2 ternary nanocomposite shows better photooxidation efficiency (62%) compared to Ag-TiO2 (38%), GO-TiO2 (9%), GO (17%), and TiO2 (8%) toward phenol degradation. The GO/Ag-TiO2 is also having the highest photocatalytic activity toward the removal of phenol under visible light irradiation (34%). The ternary heterostructure (85%) also possesses superior photooxidation activity compared to Ag-TiO2 (44%) and GO-TiO2 (71%) toward the degradation of p-nitrophenol under UV light radiation for 60 min. The above observation reveals that the cooperative effect of Ag, TiO2, and GO is playing a crucial role to result in the high photooxidation activity of the GO/Ag-TiO2 hetero-nanocomposites.

Valence modulation and morphological engineering of MoO3 as high-performance cathode for aqueous zinc ion batteries

Molybdenum trioxide (MoO3) has become the preferred choice of cathode materials for aqueous zinc ion batteries (AZIBs) because of their multivalency, high theoretical capacity, and unique layered structure. However, MoO3 suffers from low conductivity and poor cycling stability, which severely limits its practical application for commercialization. Here, we develop a morphological engineering couple valence modulation to remarkably enhance the Zn2+ storage capability of commercial MoO3 powder. Uniform MoO3 with low-valence-state Mo (denoted as MoO3−x) nanoparticles are readily manufactured through a simple solvothermal method with ethylene glycol as a reductant. Taking the merits of the increased electrical conductivity, Zn2+ diffusion rate and active sites, the Zn//MoO3−x battery achieves a boosted capacity of 144 mAh g−1 at 2 A g−1, substantially superior to the Zn//MoO3 one (only 17 mAh g−1). In addition, the Zn//MoO3−x battery exhibits an excellent energy density of 146 Wh kg−1 and good cycle stability with a capacity loss of only 0.07% per cycle over 500 cycles. This work provides an attractive approach to enhance the electrochemical properties of molybdenum-based materials and may open new idea to design advanced cathode material for AZIBs.

Flexible free-standing BixSey@C/PEDOT:PSS thermoelectric composite film with high-performance electromagnetic interference shielding

Due to the component advantages and structural features, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) based inorganic–organic composite films shows huge application potential in various fields. However, there are few reports on the bi-functions of thermoelectric (TE) and electromagnetic interference (EMI) shielding for the PEDOT:PSS-based functional films. Herein, metal–organic frameworks (MOFs)-derived BixSey@C sheets with average size about ∼ 7.32 μm are obtained via the solvothermal reaction and selenization pyrolysis treatment, and then flexible free-standing BixSey@C/PEDOT: PSS (BSCP) composite films are obtained by a feasible vacuum filtration combined with cold pressing treatment, using different contents of BixSey@C content as inorganic component. Micrometer BixSey@C sheets are uniformly dispersed in the PEDOT:PSS matrix constructing bi-functional composite films with unique layered structure. When the MOFs-derived BixSey@C content is 70%, BSCP-70 composite film gets a power factor of 11.23 μW m−1 K−2 at 340 K. Meanwhile, the BSCP-70 composite film reaches the highest average total EMI shielding effectiveness (SET) value of 45.0 dB at only 41.9 μm thickness at X-band. Based on multi-physical properties of MOF-derived BixSey@C and PEDOT:PSS, flexible BixSey@C/PEDOT:PSS composite films display good application potentiality in the flexible TE devices and EMI shielding protection.

Boosting the sonophotocatalytic performance of BiOCl by Eu doping: DFT and an experimental study

Bismuth oxychloride (BiOCl) has a unique layered structure and uneven charge distribution, resulting in an internal electric field under polarization, which promotes the efficient separation and migration of photogenerated carriers. BiOCl could be a candidate for sonophotocatalysts. However, the low utilization of visible light limits the application of BiOCl in photocatalysts. In this study, the photocatalytic performance of rare earth element (Nd, Sm, Eu, Er and Er)-doped BiOCl was studied by density functional theory (DFT) and experimentally to screen high-performance catalysts. The band structure, density of states, and optical properties were calculated by the DFT method to predict the photocatalytic activity of rare earth-doped BiOCl. The built-in electric field formed in Eu-doped BiOCl inhibiting electron and hole recombination can be observed. Subsequently, the activity of the photocatalyst and sonophotocatalysts was evaluated. The results show that the photocatalytic and sonophotocatalytic activity of Eu-doped BiOCl is improved, which is consistent with the theoretical prediction. Combining theoretical calculations with experiments, the sonophotocatalytic activity of Eu-doped BiOCl is enhanced, mainly due to the synergistic effect of inhibiting carrier recombination, and expansion to the visible light absorption region.

Controlled Synthesis of Flower-like Hierarchical NiCo-Layered Double Hydroxide Integrated with Metal-Organic Framework-Derived Co@C for Supercapacitors.

Layered double hydroxides (LDHs) have come to the foreground recently, considering their unique layered structure and short ion channels when they act as electrode materials for supercapacitors (SCs). However, due to their poor rate and cycle performance, they are not highly sought after in the market. Therefore, a flower-like hierarchical NiCo-LDH@C nanostructure with flake NiCo-LDH anchored on the carbon skeleton has emerged here, which is constructed by calcination and hydrothermal reaction and applying flake ZIF-67 as a precursor. In this structure, NiCo-LDH grows outward with abundant and homogeneously distributed Co nanoparticles on Co@C as nucleation sites, forming a hierarchical structure that is combined tightly with the carbon skeleton. The flower-like hierarchical nanostructures formed by the composite of metal-organic frameworks (MOFs) and LDHs have successfully enhanced the cycle and rate performance of LDH materials on the strength of strong structural stability, large specific surface area, and unique cooperative effect. The NiCo-LDH@C electrode displays superb electrochemical performance, with a specific capacitance of 2210.6 F g-1 at 1 A g-1 and 88.8% capacitance retention at 10 A g-1. Furthermore, the asymmetric supercapacitor (ASC) constructed with NiCo-LDH@C//RGO reveals a remarkable energy density of 45.02 W h kg-1 with a power density of 799.96 W kg-1. This project aims to propose a novel avenue to exploit NiCo-LDH electrode materials and provide theory and methodological guidance for deriving complex structures from MOF derivatives.

Exfoliation behavior and superior photothermal conversion performance of MXenes beyond Ti3C2Tx

Two dimensional transition metal carbides (MXenes) have attracted significant interest due to their unique layer structure, chemical diversity and superior physiochemical performances. However, most studies have focused on Ti3C2Tx, and the synthesis process and photothermal conversion capability of other MXenes remain unclear. In this work, we have systematically investigated the exfoliation behavior of six different MXenes, including mono-transition-metal (Ti3C2Tx, V2CTx, and Nb2CTx) and double-transition-metal (TiVCTx, TiNbCTx, and NbVCTx) MXenes derived from MAX phases, integrated with their photothermal conversion performance by combining experimental and theoretical studies. The phase, morphology, composition and surface groups of the different MXenes have been analyzed using XRD, SEM, XPS, and HRTEM techniques. Our results indicate a systematic variation in etching difficulty from difficult to easy, as Nb2AlC > NbVAlC > V2AlC > TiNbAlC > TiVAlC > Ti3AlC2, which correlates with the chemical composition and etching duration. Furthermore, the exfoliation factor m from density functional theory calculations reveals that the bond energies of M−A bonds are much weaker than M−X bonds in MAX phases, which agrees well with the experimental results. Interestingly that, all the obtained MXenes exhibit remarkable photothermal conversion performance with fast response, where the MXenes beyond Ti3C2Tx, such as V2CTx, NbVCTx, Nb2CTx, TiVCTx, and TiNbCTx, display higher saturation temperature of 95, 88, 81, 78, and 71 °C, respectively, than that of Ti3C2Tx (65 °C). These findings could potentially facilitate the efficient design and development of diverse MXene materials with outstanding photothermal conversion performance for applications in wearable devices, biomedical technology and solar water desalination.

Co-doped SnS microsphere decorated carbon nanofiber flexible films for supercapacitor applications

SnS is an ideal material for supercapacitors because of its unique layered structure and excellent electrochemical performance, but the research of SnS based electrode materials of flexible self-supporting supercapacitors has been rarely exploited. In this study, microsphere like Co doped SnS grown on carbon nanofibers (Co-SnS@CNF) was prepared by electrospinning, hydrothermal method and annealing treatment. Co-SnS@CNF has great flexibility, high specific capacitance, excellent rate performance and cycle stability. Specifically, the specific capacitance is 750 F g−1 at the current density of 1 A g−1. The special microsphere structure with more electrochemical active sites and lower resistance of ion and charge transfer by Co doping are responsible for the superior electrochemical performances. Furthermore, when assembled Co-SnS@CNF as the symmetrical supercapacitor device, the energy density of 20.89 Wh Kg−1 and the power density of 376 W Kg−1 are achieved at the current density of 1 A g−1, while showing ultra-high cycle stability. Therefore, the Co-SnS@CNF offers excellent application potential for flexible self-supporting supercapacitors.

In-situ growth of 3D porous tunnel-like NaV6O15@C on carbon cloth as high-capacity zinc ion battery cathode

As a widely used electrode material, carbon cloth possesses the advantages of a stable self-supporting structure and fast electron conduction rate. Sodium vanadate has gradually attracted the attention of researchers owing to its unique layered tunnel-like structure. In this work, in-situ growth of NaV6O15 on carbon fiber with a 3D porous tunnel-like structure for cathode material of aqueous zinc ion batteries is reported. NaV6O15 nanorods are uniformly dispersed on the surface of carbon cloth fibers and coated perfectly, which intertwined to form rich 3D porous tunnels. The as-prepared NaV6O15 @C has a reversible capacity of 487.7 mAh·g−1 at 0.1 A·g−1, which is 2.6 times that of pure NaV6O15-A. The coulomb efficiency (CE) is always maintained at 100 %, which proposed a scheme for the design of higher capacity cathode materials.

MoS2-Based Nanocomposites for Photocatalytic Hydrogen Evolution and Carbon Dioxide Reduction.

Photocatalysis is a facile and sustainable approach for energy conversion and environmental remediation by generating solar fuels from water splitting. Due to their two-dimensional (2D) layered structure and excellent physicochemical properties, molybdenum disulfide (MoS2) has been effectively utilized in photocatalytic H2 evolution reaction (HER) and CO2 reduction. The photocatalytic efficiency of MoS2 greatly depends on the active edge sites present in their layered structure. Modifications like reducing the layer numbers, creating defective structures, and adopting different morphologies produce more unsaturated S atoms as active edge sites. Hence, MoS2 acts as a cocatalyst in nanocomposites/heterojunctions to facilitate the photogenerated electron transfer. This review highlights the role of MoS2 as a cocatalyst for nanocomposites in H2 evolution reaction and CO2 reduction. The H2 evolution activity has been described comprehensively as binary (with metal oxide, carbonaceous materials, metal sulfides, and metal-organic frameworks) and ternary composites of MoS2. Photocatalytic CO2 reduction is a more complex and challenging process that demands an efficient light-responsive semiconductor catalyst to tackle the thermodynamic and kinetic factors. Photocatalytic reduction of CO2 using MoS2 is an emerging topic and would be a cost-effective substitute for noble catalysts. Herein, we also exclusively envisioned the possibility of layered MoS2 and its composites in this area. This review is expected to furnish an understanding of the diverse roles of MoS2 in solar fuel generation, thus endorsing an interest in utilizing this unique layered structure to create nanostructures for future energy applications.

Study on the performance of hydrotalcite-based ozone decomposition catalyst

AbstractOzone in the indoor environment is seriously harmful to human health, and the catalytic decomposition method is one of the most effective ozone purification technologies. The development of ozone decomposition catalyst with superior activity and stability is the bottleneck, especially under high humidity, high space velocity, and ambient temperature. Layered double hydroxide (LDH) has a unique two-dimensional layered structure and excellent water resistance. In the paper, Ni3Fe, Ni3Co, Ni3Mn, and Co3Fe hydrotalcite-structured catalysts were prepared by the coprecipitation method. And their ozone catalytic decomposition performance was tested under 30 °C, 600000 mL/(g·h), low humidity (RH < 5%), and high humidity (RH > 90%). The results showed that Ni3Co-LDH exhibited excellent ozone decomposition performance, and the ozone conversion was 88% and 77% under low humidity and high humidity, respectively. Combined with XRD, BET, SEM, XPS, Raman, FT-IR, TG and other characterizations, the intrinsic mechanism of the excellent ozone decomposition performance of LDH catalysts was revealed. The paper provided new ideas for developing transition metal ozone decomposition catalysts.

MoSe2 hollow nanospheres with expanded selenide interlayers for high-performance aqueous zinc-ion batteries

Transition metal dichalcogenides (TMDs) as materials for aqueous zinc-ion batteries (ZIBs) have received a lot of interest because of their large theoretical capacity and unique layered structure. However, the sluggish kinetics and inferior cyclic stability limit the usefulness of ZIBs. In the present investigation, the interlayer spacing enlarged MoSe2 hollow nanospheres comprised of nanosheets with ultrathin shells have been successfully synthesized through a combined strategy of template assistance and anion-exchange reaction. The hierarchical ultrathin nanosheets and hollow structure effectively suppress the agglomeration of pure nanosheets and ameliorate volume fluctuations induced by ion migration during (dis)charging/charging. The interlayer expansion provides good channels for the transport of Zn2+ ions and speeds up the insertion/extraction of Zn2+. In addition, in-situ carbon modification can significantly improve electronic conductivity. Therefore, the electrode prepared from MoSe2 hollow nanospheres with enlarged interlayer spacing not only exhibits outstanding cycle stability (capacity retention of 94.5% after 1600 cycles) but also exhibits high-rate capability (266.1 mA h g−1 at 0.1 A g−1 and 203.6 mA h g−1 at 3 A g−1). This work could provide new insights into the design of cathode using TMDs of hollow structure for Zn2+ storage.

MoS2 nanoflowers implanted in nitrogen-doped carbon fibers with Fe2O3 nanoparticles decorated for enhanced lithium storage performance

MoS2 has attracted extensive attention due to its unique two-dimensional layered structure and high theoretical capacity. Unfortunately, the large volume variation and sluggish lithiation kinetics during charging/discharging result in low-rate capability and poor cyclic stability. To solve those issues, MoS2/Fe2O3 @ carbon fiber (CNF) composite was designed delicately by implanting MoS2 nanoflowers in nitrogen-doped carbon fibers with Fe2O3 nanoparticles decorated. The carbon nano-fibers served as a holder to accommodate the volume expansion of MoS2 and provide a high-speed channel for electron transport, while Fe2O3 nanoparticles are apt to form heterojunction with MoS2, producing an internal electric field to enhance the ionic dynamic. As a result, the optimized sample, denoted as MoS2/Fe2O3 @CNF-3, exhibits high first discharge capacity of ∼1370 mAh g−1 at 50 mA g−1 and excellent cycle performance (559.74 mAh g−1 after 500 cycles at 1 A g−1, with capacity retention rate of 71.6%). In summary, the design techniques of heterojunction building and carbon encapsulation can be applied to different energy storage materials and have significant potential for enhancing lithium-ion battery performance electrochemically.

Preparation and Application Analysis of MXene

As an emerging two-dimensional transition metal carbide and/or nitride in recent years, MXene has become a research hotspot in many fields such as energy storage, catalysis, and adsorption with its unique two-dimensional layered structure, large specific surface area, excellent electrical conductivity, mechanical stability and magnetic properties. In this paper, the preparation method of two-dimensional material MXenes is briefly described, and its application progress in various fields in recent years is reviewed and summarized. Finally, the existing problems at this stage and the future research direction and development prospects are analyzed.

Recent Advances in Molybdenum Disulfide and Its Nanocomposites for Energy Applications: Challenges and Development.

Energy storage and conversion are critical components of modern energy systems, enabling the integration of renewable energy sources and the optimization of energy use. These technologies play a key role in reducing greenhouse gas emissions and promoting sustainable development. Supercapacitors play a vital role in the development of energy storage systems due to their high power density, long life cycles, high stability, low manufacturing cost, fast charging-discharging capability and eco-friendly. Molybdenum disulfide (MoS2) has emerged as a promising material for supercapacitor electrodes due to its high surface area, excellent electrical conductivity, and good stability. Its unique layered structure also allows for efficient ion transport and storage, making it a potential candidate for high-performance energy storage devices. Additionally, research efforts have focused on improving synthesis methods and developing novel device architectures to enhance the performance of MoS2-based devices. This review article on MoS2 and MoS2-based nanocomposites provides a comprehensive overview of the recent advancements in the synthesis, properties, and applications of MoS2 and its nanocomposites in the field of supercapacitors. This article also highlights the challenges and future directions in this rapidly growing field.

Properties of hollow yolk-shell NiS2/FeS2@NC@NiFe LDH/FeO(OH) nanoflower microspheres as anode materials for lithium-ion batteries

As an anode material of lithium-ion batteries, transition metal sulfides have high theoretical capacity, and the structure design is an effective strategy to gain better electrochemical performance. Layered double hydroxides (LDHs) have significant preponderances in the field of energy storage on account of their exchangeable anions and biggish specific surface area. Nevertheless, its defects such as poor conductivity, easy agglomeration of nanosheets and biggish volume change during the cycle result in poor cycling durability and rate performance, which gravely constrain its further application. In this study, hollow yolk-shell NiS2/FeS2@NC@NiFe LDH/FeO(OH) nanoflower microspheres are prepared successfully by solvothermal and hydrothermal methods. Firstly, introducing N-doped carbon layer can availably heighten the electro-conductivity of the materials and stop the metallic particles from falling off to boost the structural stability. The design of hollow yolk-shell and nanoflower structure can effectively inhibit cubical expansion. In addition, the unique layered structure of the nanosheets can provide more active sites, shorten the ion transport path, and enhance the lithium storage performance. As a result, the NiS2/FeS2@NC@NiFe LDH/FeO(OH) electrode has splendid cycling performance (709.9 mAh g−1 at 0.2 A g−1 after 200 cycles). These prominent electrochemical properties demonstrate convincingly that the NiS2/FeS2@NC@NiFe LDH/FeO(OH) is a viable anode material.