Liquid Crystalline Dispersions of Graphene‐Oxide‐Based Hybrids: A Practical Approach towards the Next Generation of 3D Isotropic Architectures for Energy Storage Applications

We report the use of the spray pyrolysis method to design self‐assembled isotropic ternary architectures made up of reduced graphene oxide (GO), functionalized multiwalled carbon nanotubes, and nickel oxide nanoparticles for cost‐effective high‐performance supercapacitor devices. Electrodes fabricated from this novel ternary system exhibit exceptionally high capacitance (2074 Fg^?1) due to the highly conductive network, synergistic link between GO and carbon nanotubes and achieving high surface area monodispersed NiO decorated rGO/CNTs composite employing the liquid crystallinity of GO dispersions. To further assess the practicality of this material for supercapacitor manufacture, we assembled an asymmetric supercapacitor device incorporating activated carbon as the anode. The asymmetric supercapacitor device showed remarkable capacity retention (>96%), high energy density (23 Wh kg^?1), and a coulombic efficiency of 99.5%.     

Hydrothermal Synthesis of Nickel Phosphate Nanorods for High‐Performance Flexible Asymmetric All‐Solid‐State Supercapacitors

Ni₂₀[(OH)₁₂(H₂O)₆][(HPO₄)₈(PO₄)₄]·12H₂O nanorods are successfully synthesized via a one‐pot hydrothermal reaction. A high‐performance flexible asymmetric all‐solid‐state supercapacitor based on the obtained Ni₂₀[(OH)₁₂(H₂O)₆][(HPO₄)₈(PO₄)₄]·12H₂O nanorods (positive electrode) and graphene nanosheets (negative electrode) is successfully assembled. It is the first report of this nanomaterial applied for all‐solid‐state supercapacitors. Interestingly, a maximum volumetric energy density of 0.446 mW h cm^?3 at a current density of 0.5 mA cm^?2 and a maximum power density of 44.1 mW cm^?3 at a current density of 6.0 mA cm^?2 are achieved by the as‐assembled device. What's more, the device also shows excellent mechanical flexibility and little capacitance change after over 5000 charge/discharge cycles at a current density of 0.5 mA cm^?2.     

Hierarchically Porous NaCoPO4–Co3O4 Hollow Microspheres for Flexible Asymmetric Solid‐State Supercapacitors

A template‐free hydrothermal method is developed to prepare hierarchical hollow precursors. An inside‐out Ostwald ripening mechanism is proposed to explain the formation of the hollow structure. After the calcination in the air, hierarchically meso/macroporous NaCoPO₄–Co₃O₄ hollow microspheres can easily be obtained. When being evaluated as electrode materials for a supercapacitor, the hierarchically porous NaCoPO₄–Co₃O₄ hollow microspheres electrode shows a specific capacitance of 268 F g^?1 at 0.8 A g^?1 and offers a good cycle life. More importantly, the obtained materials are successfully applied to fabricate flexible solid‐state asymmetric supercapacitors. The device exhibits a specific capacitance of 28.6 mF cm^?2 at 0.1 mA cm^?2, a good cycling stability with only 5.5% loss of capacitance after 5000 cycles, and good mechanical flexibility under different bending angles, which confirms that the hierarchically porous NaCoPO₄–Co₃O₄ hollow microspheres are promising active materials for the flexible supercapacitor.     

Three‐Dimensional Multilayer Assemblies of MoS2/Reduced Graphene Oxide for High‐Performance Lithium Ion Batteries

Three‐dimensional (3D) multilayer molybdenum disulfide (MoS₂)/reduced graphene oxide (RGO) nanocomposites are prepared by a solution‐processed self‐assembly based on the interaction using different sizes of MoS₂ and GO nanosheets followed by in situ chemical reduction. 3D multilayer assemblies with MoS₂ wrapped by large RGO nanosheets and good interface are observed by transmission electron microscopy. The interaction of Na⁺ ions with oxygen‐containing groups of GO is also investigated. The measurement of lithium ion batteries (LIBs) shows that MoS₂/RGO anode nanocomposite with a weight ratio of MoS₂ to GO of 3:1 exhibits an excellent rate performance of 750 mAh g^?1 at 3 A g^?1 outperforming many previous studies and a high reversible capacity up to ≈1180 mAh g^?1 after 80 cycles at 100 mA g^?1. Good rate performance and high capacity of MoS₂/RGO with 3D unique layered‐structures are attributed to the combined effects of continuous conductive networks of RGO, good interface facilitating charge transfer, and strong RGO sheets preventing the volume expansion. Results indicate that 3D multilayer MoS₂/RGO prepared by a facile solution‐processed assembly can be developed to be an excellent nanoarchitecture for high‐performance LIBs.     

Transition of hexagonal to square sheets of Co3O4 in a triple heterostructure of Co3O4/MnO2/GO for high performance supercapacitor electrode

Cobalt oxide and manganese oxides are promising electrode materials amongst the transition metal oxides (TMOs) for pseudocapacitors. The lack of reversibility and deterioration of capacitance at higher current densities is major flaw in Co₃O₄ as an electrode for supercapacitor while MnO₂ suffers from low electrical conductivity and poor cycling stability. It is inevitable to bridge the performance gap between these two TMOs to obtain a high performance supercapacitor based on environmental benign and earth abundant materials. Herein, we fabricated a hybrid triple heterostructure high-performing supercapacitor based on hexagonal sheets of Co₃O₄, MnO₂ nanowires and graphene oxide (GO) to form a composite structure of Co₃O₄/MnO₂/GO by all hydrothermal synthesis route. The Co₃O₄ square sheets serves as an excellent backbone with good mechanical adhesion with the current collector providing a rapid electronic transfer channel while the integrated nanostructure of MnO₂ NW/GO permits more electrolyte ions to penetrate capably into the hybrid structure and allows effective utilization of more active surface areas. A triple heterostructured device exhibits a high areal capacitance of 3087 mF cm⁻² at 10 mV s⁻¹ scan rate along with the exceptional rate capability and cycling stability having capacitance retention of ∼170% after 5000 charge/discharge cycles. The TMOs based pseudocapacitor with the conducting scaffolds anchoring based on graphene derivatives like this will pave an encouraging alternatives for next generation energy storage devices.     

Flexible Ti‐Doped FeOOH Quantum Dots/Graphene/Bacterial Cellulose Anode for High‐Energy Asymmetric Supercapacitors

Ti‐doped FeOOH quantum dots (QD) decorated on graphene (GN) sheets are designed and fabricated by a facile and scalable synthesis route. Importantly, the Ti‐doped FeOOH QD/GN are successfully dispersed within bacterial cellulose (BC) substrate as bending anode with large loading mass for flexible supercapacitor. By virtue of its favorable architecture, this composite electrode exhibits a remarkable areal capacitance of 3322 mF cm^?2 at 2 mA cm^?2, outstanding cycle performance (94.7% capacitance retention after 6000 cycles), and excellent mechanical strength (68.7 MPa). To push the energy density of flexible supercapacitors, the optimized asymmetric supercapacitor using Mn₃O₄/GN/BC as positive electrode and Ti‐doped FeOOH QD/GN/BC as negative electrode can be cycled reversibly in the operating voltage range of 0–1.8 V and displays ultrahigh areal energy density of 0.541 mWh cm^?2, ultrahigh volumetric energy density of 9.02 mWh cm^?3, reasonable cycling performance (9.4% decay in specific capacitance after 5000 cycles), and good capacitive retention at bending state.     

Facile Construction of 3D Reduced Graphene Oxide Wrapped Ni3S2 Nanoparticles on Ni Foam for High‐Performance Asymmetric Supercapacitor Electrodes

3D reduced graphene oxide (rGO)‐wrapped Ni₃S₂ nanoparticles on Ni foam with porous structure is successfully synthesized via a facile one‐step solvothermal method. This unique structure and the positive synergistic effect between Ni₃S₂ nanoparticles and graphene can greatly improve the electrochemical performance of the NF@rGO/Ni₃S₂ composite. Detailed electrochemical measurements show that the NF@rGO/Ni₃S₂ composite exhibits excellent supercapacitor performance with a high specific capacitance of 4048 mF cm^?2 (816.8 F g^?1) at a current density of 5 mA cm^?2 (0.98 A g^?1), as well as long cycling ability (93.8% capacitance retention after 6000 cycles at a current density of 25 mA cm^?2). A novel aqueous asymmetric supercapacitor is designed using the NF@rGO/Ni₃S₂ composite as positive electrode and nitrogen‐doped graphene as negative electrode. The assembled device displays an energy density of 32.6 W h kg^?1 at a power density of 399.8 W kg^?1, and maintains 16.7 W h kg^?1 at 8000.2 W kg^?1. This outstanding performance promotes the as‐prepared NF@rGO/Ni₃S₂ composite to be ideal electrode materials for supercapacitors.     

Graphene‐Based Phosphorus‐Doped Carbon as Anode Material for High‐Performance Sodium‐Ion Batteries

Graphene‐based phosphorus‐doped carbon (GPC) is prepared through a facile and scalable thermal annealing method by triphenylphosphine and graphite oxide as precursor. The P atoms are successfully doped into few layer graphene with two forms of P–O and P–C bands. The GPC used as anode material for Na‐ion batteries delivers a high charge capacity 284.8 mAh g^?1 at a current density of 50 mA g^?1 after 60 cycles. Superior cycling performance is also shown at high charge?discharge rate: a stable charge capacity 145.6 mAh g^?1 can be achieved at the current density of 500 mA g^?1 after 600 cycles. The result demonstrates that the GPC electrode exhibits good electrochemical performance (higher reversible charge capacity, super rate capability, and long‐term cycling stability). The excellent electrochemical performance originated from the large interlayer distance, large amount of defects, vacancies, and active site caused by P atoms doping. The relationship of P atoms doping amount with the Na storage properties is also discussed. This superior sodium storage performance of GPC makes it as a promising alternative anode material for sodium‐ion batteries.     

Fabrication of Ni-Co binary oxide/reduced graphene oxide composite with high capacitance and cyclicity as efficient electrode for supercapacitors

Nickel-cobalt binary oxide/reduced graphene oxide (G-NCO) composite with high capacitance is synthesized via a mild method for electrochemical capacitors. G-NCO takes advantages of reduced graphene oxide (RGO) and nickel-cobalt binary oxide. As an appropriate matrix, RGO is beneficial to form homogeneous structure and improve the electron transport ability. The binary oxide owns more active sites than those of nickel oxide and cobalt oxide to promote the redox reaction. Attributed to the well crystallinity, homogeneous structure, increased active sites, and improved charge transfer property, the G-NCO composite exhibits highly enhanced electrochemical performance compared with G-NiO and G-Co₃O₄ composites. The specific capacitance of the G-NCO composite is about 1750 F g^?1 at 1 A g^?1 together with capacitance retention of 79 % (900/1138 F g^?1) over 10,000 cycles at 4 A g^?1. To research its practical application, an asymmetric supercapacitor with G-NCO as positive electrode and activated carbon as negative electrode was fabricated. The asymmetric device exhibits a prominent energy density of 37.7 Wh kg^?1 at a power density of 800 W kg^?1. The modified G-NCO composite shows great potential for high-capacity energy storage.     

Hydrothermal synthesis of carbon- and reduced graphene oxide-supported CoMoO4 nanorods for supercapacitor

Hybrid CoMoO₄ nanorods with carbon (C) and graphene oxide (rGO) are successfully synthesized via one-step hydrothermal process. Hybrid α-CoMoO₄ nanorods have shown excellent electrochemical performances compared to pristine CoMoO₄ in alkaline electrolyte. Specifically, CoMoO₄/C nanorod exhibits a maximum specific capacitance of 451.6 F g^?1 at the current density of 1 A g^?1, whereas CoMoO₄/rGO shows high specific capacitance of 336.1 F g^?1 at the same current density. Both the hybrid nanorods show good rate capability even at high current density of 20 A g^?1 and long-term cyclic stability. The observed electrochemical features of the hybrid CoMoO₄ nanostructure could be attributed to the presence of highly conductive carbonaceous material on unique one-dimensional nanorod microstructure which enhances the electrical conductivity of the nanorods thereby allowing faster electrolyte ion diffusion during the redox process.     

Rapid,Microwave‐Assisted,and One‐Pot Synthesis of Magnetic Palladium–CoFe2O4–Graphene Composite Nanosheets and Their Applications as Recyclable Catalysts

Here, a microwave‐assisted approach has been demonstrated to rapidly prepare magnetic Pd–CoFe₂O₄–graphene (GE) composite nanosheets in ethylene glycol (EG) solvent. The generation of both Pd and CoFe₂O₄ nanoparticles is accompanied with the reduction process of graphene oxide (GO) by EG. The surface morphologies and chemical composition of the composite nanosheets are characterized by transmission electron microscopy (TEM), energy‐dispersive X‐ray spectrometer (EDS), powder X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) measurements. The as‐prepared Pd–CoFe₂O₄–GE composite nanosheets exhibit a remarkable catalytic activity towards the reduction of 4‐nitrophenol by sodium borohydride (NaBH₄) at room temperature. The apparent kinetic rate constant (K _app) of this catalytic reaction could reach about 11.0 × 10^?3 s^?1. Moreover, the CoFe₂O₄ component exhibits a magnetic property, which could make the Pd–CoFe₂O₄–GE composite nanocatalysts separated from the suspension system. The catalytic conversion of the 4‐nitrophenol to 4‐aminophenol could reach 87.2% after four cycles. This work presents a simple, rapid, and versatile method to fabricate both metal and spinel‐type complex oxides on GE nanosheets, providing a new opportunity for their applications in the recyclable catalytic reaction.     

Conformational analysis of 3‐methyl‐3‐silathiane and 3‐fluoro‐3‐methyl‐3‐silathiane

The conformational equilibria of 3‐methyl‐3‐silathiane 5 , 3‐fluoro‐3‐methyl‐3‐silathiane 6 and 1‐fluoro‐1‐methyl‐1‐silacyclohexane 7 have been studied using low temperature ¹³C NMR spectroscopy and theoretical calculations. The conformer ratio at 103 K was measured to be about 5 _ax: 5 _eq = 15:85, 6 _ax: 6 _eq = 50:50 and 7 _ax: 7 _eq = 25:75. The equatorial preference of the methyl group in 5 (0.35 kcal mol^?1) is much less than in 3‐methylthiane 9 (1.40 kcal mol^?1) but somewhat greater than in 1‐methyl‐1‐silacyclohexane 1 (0.23 kcal mol^?1). Compounds 5–7 have low barriers to ring inversion: 5.65 (ax → eq) and 6.0 (eq → ax) kcal mol^?1 ( 5 ), 4.6 ( 6 ), 5.1 (Me_ax → Me_eq) and 5.4 (Me_eq → Me_ax) kcal mol^?1 ( 7 ). Steric effects cannot explain the observed conformational preferences, like equal population of the two conformers of 6 , or different conformer ratio for 5 and 7 . Actually, by employing the NBO analysis, in particular, considering the second order perturbation energies, vicinal stereoelectronic interactions between the Si–X and adjacent C–H, C–S, and C–C bonds proved responsible. Copyright © 2010 John Wiley & Sons, Ltd.     

Epitaxial Growth of Urchin‐Like CoSe2 Nanorods from Electrospun Co‐Embedded Porous Carbon Nanofibers and Their Superior Lithium Storage Properties

A facile synthesis of porous graphitic carbon nanofibers (CNFs) with encapsulated Co nanoparticles (denote as Co@CNFs) via electrospinning and subsequent annealing is reported. The in situ generated Co nanoparticles (NPs) promote the CNF graphitization under a low temperature of 700 °C, which simultaneously results in the porous structure of the Co@CNFs with a large surface area (416 m² g^?1). Furthermore, urchin‐like CoSe₂ nanorods are epitaxially grown from the Co@CNFs via a facile hydrothermal selenation, in which the embedded Co NPs serve as directing seeds and sacrificial Co‐source, and CoSe₂ nanorods are rooted into the CNFs (denote as CoSe₂@CNFs). When used as anode materials for lithium ion batteries, the CoSe₂@CNFs demonstrate superior lithium storage properties, delivering a high reversible capacity of 1405 mA h g^?1 after 300 cycles at a current density of 200 mA g^?1. The enhanced lithium storage performance can be attributed to the novel hybrid structure, namely, the porous and graphitic CNFs can not only facilitate the charge/ion transfer but also buffer the volume changes of the electrode during lithiation/delithiation processes. More importantly, a general strategy is provided to graphitize amorphous carbon materials via the use of in situ generated transition metal nanoparticles as catalyst.     

Core–Shell Composite Synthesized through In Situ Polymerization in Emulsion with High Electrical Conductivity Sensitive to Humidity

A core–shell composite has been synthesized through in situ polymerization in emulsion with an average of 205 nm of diameter. Each composite consists of a graphene oxide (GO) core and a poly(methyl methacrylate/butyl acrylate) shell. The latex is homogeneous without any aggregation after stability testing in normal temperature for 100 d and can be applied as an ideal conductive adhesive whose glass transition temperature (T _g) is under ?30 °C and lucid conductive film whose T _g is above 17 °C. There exists half core–shell structure in the composite with part of GO exposed which contributes to the electrical conductivity of film formed by composite. The electrical conductivity of the composite is sensitive to humidity, increasing from 0.233 to 0.357 S m^?1, while the related humidity ranges from 0% to 60%. The flexible aliphatic shell established by polyacrylate chains with nanolevel of interspaces makes it easy for hydrone to move in and interact with the oxygen groups on the chains, and then the interaction enhances the difficulty for hydrone to move out, on account of which film formed by core–shell composite can hold hydrone and exhibit advanced electrical conductivity in high humidity atmosphere.     

Catalysis by hydrogen chloride in the gas‐phase elimination kinetics of 2‐phenyl‐2‐propanol and 3‐methyl‐1‐buten‐3‐ol

A homogeneous, molecular, gas‐phase elimination kinetics of 2‐phenyl‐2‐propanol and 3‐methyl‐1‐ buten‐3‐ol catalyzed by hydrogen chloride in the temperature range 325–386 °C and pressure range 34–149 torr are described. The rate coefficients are given by the following Arrhenius equations: for 2‐phenyl‐2‐propanol log k₁ (s^?1) = (11.01 ± 0.31) ? (109.5 ± 2.8) kJ mol^?1 (2.303 RT)^?1 and for 3‐methyl‐1‐buten‐3‐ol log k₁ (s^?1) = (11.50 ± 0.18) ? (116.5 ± 1.4) kJ mol^?1 (2.303 RT)^?1. Electron delocalization of the CH₂?CH and C₆H₅ appears to be an important effect in the rate enhancement of acid catalyzed tertiary alcohols in the gas phase. A concerted six‐member cyclic transition state type of mechanism appears to be, as described before, a rational interpretation for the dehydration process of these substrates. Copyright © 2007 John Wiley & Sons, Ltd.     

Raman spectroscopy and characterisation of α‐gallium oxyhydroxide and β‐gallium oxide nanorods

Raman spectroscopy complemented by infrared spectroscopy was used to characterise both gallium oxyhydroxide (α‐GaO(OH)) and gallium oxide (β‐Ga₂O₃) nanorods synthesised with and without the surfactants using a soft chemical methodology at low temperatures. Nano‐ to micro‐sized gallium oxyhydroxide and gallium oxide materials were characterised and analysed by both X‐ray diffraction and Raman spectroscopy. Rod‐like GaO(OH) crystals with average length of ∼2.5 µm and width of 1.5 µm were obtained. Upon thermally treating gallium oxyhydroxide GaO(OH) to 900 °C, β‐Ga₂O₃ was synthesised retaining the initial GaO(OH) morphology. Raman spectroscopy has been used to study the structure of nanorods of GaO(OH) and Ga₂O₃ crystals. Raman spectroscopy shows bands characteristic of GaO(OH) at 950 and ∼1000 cm⁻¹ attributed to Ga OH deformation modes. Bands at 261, 275, 433 and 522 cm⁻¹ are assigned to vibrational modes involving Ga OH units. Bands observed at 320, 346, 418 and 472 cm⁻¹ are assigned to the deformation modes of Ga₂O₆ octahedra. Two sharp infrared bands at 2948 and 2916 cm⁻¹ are attributed to the GaO(OH) symmetric stretching vibrations. Raman spectroscopy of Ga₂O₃ provides bands at 630, 656 and 767 cm⁻¹ which are assigned to the bending and stretching of GaO₄ units. Raman bands at 417 and 475 cm⁻¹ are attributed to the symmetric stretching modes of GaO₂ units. The Raman bands at 319 and 347 cm⁻¹ are assigned to the bending modes of GaO₂ units. Copyright © 2008 John Wiley & Sons, Ltd.     

Facile Synthesis of Single‐Phase Mesoporous Gd2O3:Eu Nanorods and Their Application for Drug Delivery and Multimodal Imaging

In this work, a new and facile strategy is developed to synthesize a single‐phase Eu³⁺‐doped mesoporous gadolinium oxide nanorods (MS‐Gd₂O₃:Eu@PEG) by incorporating a facile wet‐chemical route, which includes an induced silica layer being coated onto the nanorods, and evolution of pores and formation of channels, as well as a surface‐modified process for multimodal imaging and anti‐cancer drug delivery. The properties of these as‐prepared Gd₂O₃:Eu nanorods are characterized by transmission electron microscopy (TEM), X‐ray diffraction (XRD), N₂ adsorption/desorption, and photoluminescence (PL). The in vitro cytotoxicity test, drug loading, and drug release experiments reveal that the MS‐Gd₂O₃:Eu@PEG nanorods have good biocompatibility, efficient loading capacity, and pH‐sensitive releasing behavior, suggesting the nanorods could be an ideal candidate as drug delivery vehicles for cancer therapy. Furthermore, the MS‐Gd₂O₃:Eu@PEG nanorods show clearly dose‐dependent contrast enhancement in T₁‐weighted magnetic resonance images and can potentially be used as a T₁‐positive contrast agent. These results indicate our prepared multifunctional mesoporous gadolinium oxide nanorods can serve as a promising platform for simultaneous anti‐cancer drug delivery and multimodal imaging.     

Influences of interfacial adhesion on gas barrier property of functionalized graphene oxide/ultra-high-molecular-weight polyethylene composites with segregated structure

The segregated graphene oxide(GO)/ultra-high-molecular-weight polyethylene (UHMWPE) composite films with various interfacial adhesion property were prepared by mechanical blending method from UHMWPE, GO, dodecyl amine (DA) functionalized graphene oxide(DA–GO) or uniform DA–GO/high density polyethylene (DA–GO/HDPE) powder. The results of XRD and XPS indicated that DA chain was successfully grafted onto GO sheets via a chemical method, which enhanced the interfacial adhesion between UHMWPE particles and GO sheets. The characterizations of POM and SEM proved that good segregated structure was only obtained in DA–GO/UHMWPE or DA–GO/HDPE/UHMWPE composite. Strong interfacial adhesion between fillers and matrix exhibits positive effect on gas barrier property. Compared to the GO/UHMWPE composite film, dramatic decrease in O₂ permeability coefficient by 42.2 and 48.1%, from 15.4 × 10^?14 to 8.9 × 10^?14 and 8.0 × 10^?14 cm³ cm cm^?2 s^?1 Pa^?1, is achieved upon the addition of only 0.5 wt% fillers, respectively. The DSC results demonstrated that the enhanced gas barrier performance was ascribed to the strong interfacial adhesion between DA–GO/HDPE and UHWMPE matrix, rather than the crystallinity of UHWMPE matrix. Additionally, the decrease in UHMWPE particle size might be conducive to improving the gas barrier property of composite films due to the formation of more isolation layers perpendicular to the film plane.     

Facile Synthesis of Gd(OH)3‐Doped Fe3O4 Nanoparticles for Dual‐Mode T1‐ and T2‐Weighted Magnetic Resonance Imaging Applications

The facile hydrothermal synthesis of polyethyleneimine (PEI)‐coated iron oxide (Fe₃O₄) nanoparticles (NPs) doped with Gd(OH)₃ (Fe₃O₄‐Gd(OH)₃‐PEI NPs) for dual mode T₁‐ and T₂‐weighted magnetic resonance (MR) imaging applications is reported. In this approach, Fe₃O₄‐Gd(OH)₃‐PEI NPs are synthesized via a hydrothermal method in the presence of branched PEI and Gd(III) ions. The PEI coating onto the particle surfaces enables further modification of poly(ethylene glycol) (PEG) in order to render the particles with good water dispersibility and improved biocompatibility. The formed Fe₃O₄‐Gd(OH)₃‐PEI‐PEG NPs have a Gd/Fe molar ratio of 0.25:1 and a mean particle size of 14.4 nm and display a relatively high r₂ (151.37 × 10^?3m ^?1 s^?1) and r₁ (5.63 × 10^?3m ^?1 s^?1) relaxivity, affording their uses as a unique contrast agent for T₁‐ and T₂‐weighted MR imaging of rat livers after mesenteric vein injection of the particles and the mouse liver after intravenous injection of the particles, respectively. The developed Fe₃O₄‐Gd(OH)₃‐PEI‐PEG NPs may hold great promise to be used as a contrast agent for dual mode T₁‐ and T₂‐weighted self‐confirmation MR imaging of different biological systems.     

Porous Silicon@Polythiophene Core–Shell Nanospheres for Lithium‐Ion Batteries

Polythiophene‐coated porous silicon core–shell nanospheres (Si@PTh) composite are synthesized by a simple chemical oxidative polymerization approach. The polythiophene acts as a flexible layer to hold silicon grains when they are repeatedly alloying/dealloying with lithium during the discharge/charge process. The long lifespan and high‐current‐density rate ­capability (at a current of 8 A g^?1) of the Si@PTh composite are vastly improved compared with as‐prepared Si spheres. Typically, these Si@PTh composite electrodes achieve a reversible capacity of 1130.5 mA h g^?1 at 1 A g^?1 current density after 500 cycles, and can even possess a discharge capacity up to 451.8 mA h g^?1 at 8 A g^?1. The improved electrochemical performance can be ascribed to the synergy effects of the flexible PTh coating and the distinctive core–shell nanospheres with porous structure, which can largely alleviate the volume expansion of the Si during alloying with lithium.