Enhanced Lithium Storage Performance of α-MoO3/CNTs Composite Cathode

Orthorhombic molybdenum oxide (α-MoO3), as a one-layered pseudocapacitive material, has attracted widespread attention due to its high theoretical lithium storage specific capacity (279 mAh/g) for lithium-ion batteries' cathode. Nevertheless, low conductivity, slack reaction kinetics, and large volume change during Li+ ions intercalation and deintercalation seriously limit the practical application of α-MoO3. Herein, we added a small number of CNTs (1.76%) to solve these problems in a one-step hydrothermal process for preparing the α-MoO3/CNTs composite. Because of the influence of CNTs, the α-MoO3 nanobelt in the α-MoO3/CNTs composite had a larger interlayer spacing, which provided more active sites and faster reaction kinetics for lithium storage. In addition, CNTs formed a three-dimensional conductive network between α-MoO3 nanobelts, enhanced the electrical conductivity of the composite, accelerated the electron conduction, shortened the ion transport path, and alleviated the structural fragmentation caused by the volume expansion during the α-MoO3 intercalation and deintercalation of Li+ ions. Therefore, the α-MoO3/CNTs composite cathode had a significantly higher rate performance and cycle life. After 150 cycles, the pure α-MoO3 cathode had almost no energy storage, but α-MoO3/CNTs composite cathode still retained 93 mAh/g specific capacity.

Optical Fiber, Nanomaterial, and THz-Metasurface-Mediated Nano-Biosensors: A Review

The increasing use of nanomaterials and scalable, high-yield nanofabrication process are revolutionizing the development of novel biosensors. Over the past decades, researches on nanotechnology-mediated biosensing have been on the forefront due to their potential application in healthcare, pharmaceutical, cell diagnosis, drug delivery, and water and air quality monitoring. The advancement of nanoscale science relies on a better understanding of theory, manufacturing and fabrication practices, and the application specific methods. The topology and tunable properties of nanoparticles, a part of nanoscale science, can be changed by different manufacturing processes, which separate them from their bulk counterparts. In the recent past, different nanostructures, such as nanosphere, nanorods, nanofiber, core-shell nanoparticles, nanotubes, and thin films, have been exploited to enhance the detectability of labelled or label-free biological molecules with a high accuracy. Furthermore, these engineered-materials-associated transducing devices, e.g., optical waveguides and metasurface-based scattering media, widened the horizon of biosensors over a broad wavelength range from deep-ultraviolet to far-infrared. This review provides a comprehensive overview of the major scientific achievements in nano-biosensors based on optical fiber, nanomaterials and terahertz-domain metasurface-based refractometric, labelled and label-free nano-biosensors.

In-situ preparation of molybdenum trioxide-silver composites for the improved photothermal catalytic performance of cyclohexane oxidation

The selective catalytic oxidation of cyclohexane has important theoretical and practical application value. However, high conversion rate and high selectivity are difficult to achieve simultaneously by conventional catalytic system. In this work, blue molybdenum trioxide (MoO₃) nanorods with oxygen vacancies were prepared by hydrothermal method using hydrated molybdic acid as a precursor under the reduction of formic acid, and in-situ produced MoO₃-silver (MoO₃-Ag) composites were further used in the photothermal catalytic oxidation of cyclohexane with high conversion and high selectivity using dry air as oxidant. The results showed that the best conversion rate of cyclohexanone and cyclohexanol (KA oil) could reach 8.6% with the selectivity of 99.0%. The excellent catalytic performance of MoO₃-Ag composites can be attributed to the significantly increased visible and near-infrared light absorption caused by the plasma resonance effect of Ag nanoparticles and oxygen vacancies, and the prevented charge recombination by MoO₃-Ag Schottky heterojunction. This work provides new reference solutions for the design and preparation of high-performance photothermal catalysts for the selective oxidation of hydrocarbons.

Cathode materials with mixed phases of orthorhombic MoO3 and Li0.042MoO3 for lithium-ion batteries

MoO3 is a promising cathode candidate for lithium-ion batteries and its electronic conductivity is usually improved by MoO3lithiation via reaction of MoO3 with LiCl solutions. However, this process might increase the manufacturing complexity and result in surface breakage of MoO3 cathodes. In this paper, by introducing lithium source into MoO3 synthesis, MoO3 can be lithiated through introduction of the Li0.042MoO3 phase into the MoO3 structure. XRD and ICP results indicate that the phase composition and lithium content can be regulated by changing the amount of lithium source in the reaction solutions. FESEM and specific surface area measurements show that the particle size becomes more uniform and the surface area is increased when the degree of MoO3 lithiation is higher. The lithiated MoO3 sample shows better cycling performance than that of pristine MoO3, which is mainly due to the enhanced conductivity and increased surface area of the lithiated MoO3.

Facile synthesis of ultrathin Ni-MOF nanobelts for high-efficiency determination of glucose in human serum

Ultrathin Ni-MOF nanobelts, [Ni₂₀(C₅H₆O₄)₂₀(H₂O)₈]·40H₂O(Ni-MIL-77 NBs), were synthesized by a facile one-pot solution process and can be used as an efficient catalyst electrode for glucose oxidation under alkaline conditions. Electrochemical measurements demonstrate that the NB/GCE, when used as a non-enzymatic glucose sensor, offers superior analytical performances with a wide linear range (from 1 μM to 500 μM), a low detection limit (0.25 μM, signal-to-noise = 3), and a response sensitivity of 1.542 μA mM^-1 cm^-2. Moreover, it can also be applied for glucose detection in human blood serum with the relative standard deviation (RSD) of 7.41%, showing the high precision of the sensor in measuring real samples.

CeO2-modified α-MoO3 nanorods as a synergistic support for Pt nanoparticles with enhanced COads tolerance during methanol oxidation

A new type of Ce-doped α-MoO₃ (Ce_0.2Mo_0.8O_3−δ) nanorod support was synthesized using a two-step hydrothermal method.

Molecular dynamics study of solvated aniline and ethylene glycol monomers confined in calcium silicate nanochannels: a case study of tobermorite

The combination of organic and inorganic materials can result in materials with extraordinary performance.

Equipment-Free Deposition of Graphene-Based Molybdenum Oxide Nanohybrid Langmuir-Blodgett Films for Flexible Electrochromic Panel Application

The potential electrochromic application of graphene-based nanohybrids is hampered by the challenges in interfacing the electrochromic nanoparticles with graphene at atomic scale and in fabricating their thin film on the substrate through a scalable method. In an effort to overcome these challenges, we demonstrate a highly dispersible graphene-based molybdenum oxide nanohybrid (mRGO-MoO3-x) for flexible electrochromic application. With only a squeeze pipet, mRGO-MoO3-x could be deposited with a high coverage on various substrates through a scalable equipment-free Langmuir-Blodgett film deposition method. By taking advantage of high transmittance benefited from its remarkable thinness, the mRGO-MoO3-x Langmuir-Blodgett film shows a superior reversible electrochromic property with high coloration efficiency on both hard and flexible substrates.

A novel polytype - the stacking fault based γ-MoO3 nanobelts

γ-MoO3 nanobelts prepared by hydrothermal synthesis were studied by synchrotron radiation powder diffraction, scanning electron microscopy, transmission electron microscopy and selected area electron diffraction. Their nm dimensions, in particular in two crystallographic directions, have a profound influence on electrochemical properties during cycling as the cathode material in lithium-ion batteries (LIBs). The diffraction analysis shows clearly that the crystal structure for the γ-MoO3 nanobelts differs significantly from that of bulk α-MoO3. The observed powder diffraction pattern, with asymmetric peaks, extremely broad peaks, as well as additional or absent diffraction peaks, is fully described by means of a model based on stacking disorder of MoO3 slabs.

Reduced graphene oxide-wrapped MoO3 composites prepared by using metal-organic frameworks as precursor for all-solid-state flexible supercapacitors

Reduced graphene oxide-wrapped MoO3M (rGO/MoO3 ) is prepared by a novel and simple method that is developed by using a metal-organic framework as the precursor. After a two-step annealing process, the obtained rGO/MoO3 composite is used for a high-performance supercapacitor electrode. Moreover, an all-solid-state flexible supercapacitor is fabricated based on the rGO/MoO3 composite, which shows stable performance under different bending states.

Facile Synthesis of Na0.33V2O5 Nanosheet-Graphene Hybrids as Ultrahigh Performance Cathode Materials for Lithium Ion Batteries

Na0.33V2O5 nanosheet-graphene hybrids were successfully fabricated for the first time via a two-step route involving a novel hydrothermal method and a freeze-drying technique. Uniform Na0.33V2O5 nanosheets with a thickness of about 30 nm are well-dispersed between graphene layers. The special sandwich-like nanostructures endow the hybrids with high discharge capacity, good cycling stability, and superior rate performance as cathodes for lithium storage. Desirable discharge capacities of 313, 232, 159, and 108 mA·h·g(-1) can be delivered at 0.3, 3, 6, and 9 A·g(-1), respectively. Moreover, the Na0.33V2O5-graphene hybrids can maintain a high discharge capacity of 199 mA·h·g(-1) after 400 cycles even at an extremely high current density of 4.5 A·g(-1), with an average fading rate of 0.03% per cycle.

Porous α-MoO3/MWCNT nanocomposite synthesized via a surfactant-assisted solvothermal route as a lithium-ion-battery high-capacity anode material with excellent rate capability and cyclability

A high-performance α-MoO3/multiwalled carbon nanotube (MWCNT) nanocomposite material is synthesized via a novel surfactant-assisted solvothermal process followed by low-temperature calcination. Its structure, composition, and morphology are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, carbon element analysis, nitrogen adsorption-desorption determination, scanning electron microscopy, and transmission electron microscopy techniques. Its electrochemical performance as a high-capacity lithium-ion-battery anode material is investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic discharge/recharge methods. This composite material exhibits not only high capacity but also excellent rate capability and cyclability. For example, when the discharge/charge current density is increased from 0.1 to 2 A g(-1), the reversible charge capacity is only decreased from 1138.3 to 941.4 mAh g(-1), giving a capacity retention of 82.7%. Even if it is cycled at a high current density of 20 A g(-1), a reversible charge capacity of 490.2 mAh g(-1) is still retained, showing a capacity retention of 43.1%. When it is repeatedly cycled at a current of 0.5 A g(-1), the initial reversible charge capacity is 1041.1 mAh g(-1). A maximum charge capacity of 1392.2 mAh g(-1) is achieved at the 292th cycle. After 300 cycles, a high charge capacity of 1350.3 mAh g(-1) is maintained. Enhancement of the electrical conduction contributed by the MWCNT composite component as well as the loose and porous texture of the MoO3/MWCNT composite is suggested to be responsible for the excellent performance.

High rate and durable, binder free anode based on silicon loaded MoO3 nanoplatelets

In order to make fast-charging batteries a reality for electric vehicles, durable, more energy dense and high-current density resistant anodes need to be developed. With such purpose, a low lithiation potential of 0.2 V vs. Li/Li⁺ for MoO₃ nanoplatelet arrays is reported here for anodes in a lithium ion battery. The composite material here presented affords elevated charge capacity while at the same time withstands rapid cycling for longer periods of time. Li₂MoO₄ and Li_1.333Mo_0.666O₂ were identified as the products of lithiation of pristine MoO₃ nanoplatelets and silicon-decorated MoO₃, respectively, accounting for lower than previously reported lithiation potentials. MoO₃ nanoplatelet arrays were deposited using hot-wire chemical vapor deposition. Due to excellent voltage compatibility, composite lithium ion battery anodes comprising molybdenum oxide nanoplatelets decorated with silicon nanoparticles (0.3% by wt.) were prepared using an ultrasonic spray. Silicon decorated MoO₃ nanoplatelets exhibited enhanced capacity of 1037 mAh g⁻¹ with exceptional cyclablity when charged/discharged at high current densities of 10 A g⁻¹.

Integrated SnO2 nanorod array with polypyrrole coverage for high-rate and long-life lithium batteries

Conversion/alloying reactions, in which more lithium ions are involved, are severely handicapped by the dramatic volume changes. A facile and versatile strategy has been developed for integrating the SnO2 nanorod array in the PPy nanofilm for providing a flexible confinement for anchoring each nanorod and maintaining the entire structural integrity and providing sustainable contact; therefore, exhibiting much more stable cycling stability (701 mA h g(-1) after 300 cycles) and better high-rate capability (512 mA h g(-1) at 3 A g(-1)) when compared with the core-shell SnO2-PPy NA.

Three dimensional metal oxides–graphene composites and their applications in lithium ion batteries

The review focuses on the effects of morphology, composition and interaction of 3d metal oxide–graphene composites on the performances of libs.

Rapid synthesis of rGO–MoO3 hybrids and mechanism of enhancing sensing performance to H2S

The 2.5 wt% rGO–MoO₃ hybrid prepared by an in situ microwave hydrothermal method has excellent sensing properties to ppm-level H₂S at 110 °C.

Fe2(MoO4)3 nanoparticle-anchored MoO3 nanowires: strong coupling via the reverse diffusion of heteroatoms and largely enhanced lithium storage properties

Fe₂(MoO₄)₃ nanoparticle-anchored MoO₃ nanowires via strong coupling via the reverse diffusion of heteroatoms and largely enhanced lithium-storage properties due to the synergistic effect of Fe₂(MoO₄)₃ nanoparticles and MoO₃ nanowires.

Graphene-based nanocomposite anodes for lithium-ion batteries

Graphene-based nanocomposites have been demonstrated to be promising high-capacity anodes for lithium ion batteries to satisfy the ever-growing demands for higher capacity, longer cycle life and better high-rate performance. Synergetic effects between graphene and the introduced second-phase component are generally observed. In this feature review article, we will focus on the recent work on four different categories of graphene-based nanocomposite anodes by us and others: graphene-transitional metal oxide, graphene-Sn/Si/Ge, graphene-metal sulfide, and graphene-carbon nanotubes. For the supported materials on graphene, we will emphasize the non-zero dimensional (non-particle) morphologies such as two dimensional nanosheet/nanoplate and one dimensional nanorod/nanofibre/nanotube morphologies. The synthesis strategies and lithium-ion storage properties of these highlighted electrode morphologies are distinct from those of the commonly obtained zero dimensional nanoparticles. We aim to stress the importance of structure matching in the composites and their morphology-dependent lithium-storage properties and mechanisms.

Network formation in graphene oxide composites with surface grafted PNIPAM chains in aqueous solution characterized by rheological experiments

Poly N-isopropyl acrylamide (PNI) radically polymerized in aqueous solution in the presence of graphene oxide (GO) can significantly change the properties of the resulting solution from a regular polymer solution to a soft solid with a GO content of only 0.176 wt% (3 wt% with respect to PNI).

Mesoporous carbon coated molybdenum oxide nanobelts for improved lithium ion storage

Mesoporous carbon-coated molybdenum oxide nanobelt composites were synthesized hydrothermally with subsequent organic–organic assembly and calcination, and used as Li-ion-battery anodes.

Graphene nanosheets encapsulated α-MoO3 nanoribbons with ultrahigh lithium ion storage properties

A facile and effective method has been reported to synthesize graphene-encapsulated α-MoO₃ nanoribbons by self-assembly of negatively charged graphene oxide and positively charged MoO₃ nanoribbons.