Binding SnO2 nanocrystals in nitrogen-doped graphene sheets as anode materials for lithium-ion batteries.

Hybrid anode materials for Li-ion batteries are fabricated by binding SnO2 nanocrystals (NCs) in nitrogen-doped reduced graphene oxide (N-RGO) sheets by means of an in situ hydrazine monohydrate vapor reduction method. The SnO2NCs in the obtained SnO2NC@N-RGO hybrid material exhibit exceptionally high specific capacity and high rate capability. Bonds formed between graphene and SnO2 nanocrystals limit the aggregation of in situ formed Sn nanoparticles, leading to a stable hybrid anode material with long cycle life.

Solution effect on diazonium-modified Au(111): reactions and structures.

Surface modifications of a Au(111) electrode with 4-bromobenzenediazonium tetrafluoroborate (BBD) in acetonitrile (ACN) and 0.1 M HClO4 have been characterized by scanning tunneling microscopy (STM). In ACN, STM results reveal the formation of disordered thin organic films.

Molecular evidence for the intermolecular S···S interaction in the surface molecular packing motifs of a fused thiophene derivative.

A microscopic investigation of the molecular packing structures of a fused thiophene derivative reveals the important role of intermolecular S···S interaction in directing the 2D self-assembly. Thermal annealing of the assembly results in the irreversible phase transition to a new structure with different molecular trimeric packing motifs.

Synthesis of MoS2 nanosheet-graphene nanosheet hybrid materials for stable lithium storage.

A facile method to synthesize a MoS(2) nanosheet-graphene nanosheet hybrid has been developed via the combination of a lithiation-assisted exfoliation process and a hydrazine monohydrate vapour reduction technique. The as-obtained nanosheet-nanosheet hybrid is more robust and exhibits much improved cycle life (>700), which make it an efficient morphological solution to the stable lithium storage problem of nanomaterials.

Globally homochiral assembly of two-dimensional molecular networks triggered by co-absorbers.

Understanding the chirality induction and amplification processes, and the construction of globally homochiral surfaces, represent essential challenges in surface chirality studies. Here we report the induction of global homochirality in two-dimensional enantiomorphous networks of achiral molecules via co-assembly with chiral co-absorbers. The scanning tunnelling microscopy investigations and molecular mechanics simulations demonstrate that the point chirality of the co-absorbers transfers to organizational chirality of the assembly units via enantioselective supramolecular interactions, and is then hierarchically amplified to the global homochirality of two-dimensional networks.

pH-responsive mechanism of a deoxycholic acid and folate comodified chitosan micelle under cancerous environment.

Smart pH-responsive polymeric micelles have attracted much attention as one of the most promising drug delivery candidates. In this paper, a different substitution of deoxycholic acid (DCA) and folic acid (FA) comodified hydroxypropyl chitosans (HPCHS) were synthesized for doxorubicin (DOX) targeted delivery and controllable release. The results indicate that the DOX-release behavior is pH-responsive and closely related with the grafting proportions of the two hydrophobic ingredients.

In situ scanning tunneling microscopy investigation of subphthalocyanine and subnaphthalocyanine adlayers on a Au(111) electrode.

The adsorption behaviors of subphthalocyanine (SubPc) and subnaphthalocyanine (SubNc) on the Au(111) surface were investigated by electrochemical scanning tunneling microscopy (ECSTM). Two types of ordered adlayer structures of SubPc were observed at 550 mV versus the reversible hydrogen electrode (RHE). All of the SubPc molecules take the Cl-down adsorption configuration on Au(111) in both structures.

Smaller sulfur molecules promise better lithium-sulfur batteries.

The lithium-sulfur battery holds a high theoretical energy density, 4-5 times that of today's lithium-ion batteries, yet its applications have been hindered by poor electronic conductivity of the sulfur cathode and, most importantly, the rapid fading of its capacity due to the formation of soluble polysulfide intermediates (Li(2)S(n), n = 4-8). Despite numerous efforts concerning this issue, combatting sulfur loss remains one of the greatest challenges. Here we show that this problem can be effectively diminished by controlling the sulfur as smaller allotropes.

Ionothermal synthesis of sulfur-doped porous carbons hybridized with graphene as superior anode materials for lithium-ion batteries.

Sulfur-doped porous carbons hybridized with graphene (SPC@G) have been synthesized via a simple ionothermal method. The obtained SPC@G nanocomposite exhibits both high capacity and excellent rate performance, making it a promising anode material for lithium-ion batteries.

Hanging Pt hollow nanocrystal assemblies on graphene resulting in an enhanced electrocatalyst.

Pt hollow nanostructures assembled by nanocrystals were in situ grown and hung onto graphene layers to combine the merits from favorable catalyst morphology control and synergetic improvement effect of the graphene support, resulting in a composite with enhanced electrocatalytic performance.

Nanocarbon networks for advanced rechargeable lithium batteries.

Carbon is one of the essential elements in energy storage. In rechargeable lithium batteries, researchers have considered many types of nanostructured carbons, such as carbon nanoparticles, carbon nanotubes, graphene, and nanoporous carbon, as anode materials and, especially, as key components for building advanced composite electrode materials. Nanocarbons can form efficient three-dimensional conducting networks that improve the performance of electrode materials suffering from the limited kinetics of lithium storage.

Facile synthesis of MoS2@CMK-3 nanocomposite as an improved anode material for lithium-ion batteries.

MoS(2)@CMK-3 nanocomposite consisting of confined nanosized MoS(2) in CMK-3 carbon matrix exhibits much improved cycling performance and rate capability due to the enlarged interlayer distance and favorable conductivity.

Block copolymer-templated chemical nanopatterning on pyrolyzed photoresist carbon films.

Block copolymer nanolithography has been extended to the nanopatterning of organic functionalities on pyrolyzed photoresist carbon films (PPFs) via diazonium chemistry, using PS-b-P4VP as the template.

Nanostructured polyaniline-decorated Pt/C@PANI core-shell catalyst with enhanced durability and activity.

We have designed and synthesized a polyaniline (PANI)-decorated Pt/C@PANI core-shell catalyst that shows enhanced catalyst activity and durability compared with nondecorated Pt/C. The experimental results demonstrate that the activity for the oxygen reduction reaction strongly depends on the thickness of the PANI shell and that the greatest enhancement in catalytic properties occurs at a thickness of 5 nm, followed by 2.5, 0, and 14 nm.

Anisotropic photoresponse properties of single micrometer-sized GeSe nanosheet.

Micrometer-sized single-crystal GeSe nanosheets have been synthesized by a solution method. The single GeSe nanosheet exhibits novel anisotropic photoresponse properties in two photodetectors based on individual nanosheet. The on/off switching ratio of the photodetector perpendicular to the nanosheet is 3.

Synthesis of nanostructured SnO2/C microfibers with improved performances as anode material for Li-ion batteries.

Nanostructured SnO2/C microfibers were prepared by thermal decomposition of tin alginate fibers produced via wet-spinning technique. Results of X-ray diffraction and scanning electron microscopy show that the as-obtained SnO2/C microfibers consist of nano-sized SnO2 crystals with a mean diameter of 10-15 nm. Transmission electron microscopy visualization reveals that the composite fibers exhibit a porous structure consisting of both micropores and mesopores.

Efficient 3D conducting networks built by graphene sheets and carbon nanoparticles for high-performance silicon anode.

The utilization of silicon particles as anode materials for lithium-ion batteries is hindered by their low intrinsic electric conductivity and large volume changes during cycling. Here we report a novel Si nanoparticle-carbon nanoparticle/graphene composite, in which the addition of carbon nanoparticles can effectively alleviate the aggregation of Si nanoparticles by separating them from each other, and help graphene sheets build efficient 3D conducting networks for Si nanoparticles. Such Si-C/G composite shows much improved electrochemical properties in terms of specific capacity and cycling performance (ca.

Rutile-TiO2 nanocoating for a high-rate Li4Ti5O12 anode of a lithium-ion battery.

Well-defined Li(4)Ti(5)O(12) nanosheets terminated with rutile-TiO(2) at the edges were synthesized by a facile solution-based method and revealed directly at atomic resolution by an advanced spherical aberration imaging technique. The rutile-TiO(2) terminated Li(4)Ti(5)O(12) nanosheets show much improved rate capability and specific capacity compared with pure Li(4)Ti(5)O(12) nanosheets when used as anode materials for lithium ion batteries. The results here give clear evidence of the utility of rutile-TiO(2) as a carbon-free coating layer to improve the kinetics of Li(4)Ti(5)O(12) toward fast lithium insertion/extraction.

Initial solid electrolyte interphase formation process of graphite anode in LiPF6 electrolyte: an in situ ECSTM investigation.

Understanding the structure and formation dynamics of the solid electrolyte interphase (SEI) on the electrode/electrolyte interface is of great importance for lithium ion batteries, as the properties of the SEI remarkably affect the performances of lithium ion batteries such as power capabilities, cycling life, and safety issues. Herein, we report an in situ electrochemical scanning tunnelling microscopy (ECSTM) study of the surface morphology changes of a highly oriented pyrolytic graphite (HOPG) anode during initial lithium uptake in 1 M LiPF(6) dissolved in the solvents of ethylene carbonate plus dimethyl carbonate. The exfoliation of the graphite originating from the step edge occurs when the potential is more negative than 1.

Improving the electrode performance of Ge through Ge@C core-shell nanoparticles and graphene networks.

Germanium is a promising high-capacity anode material for lithium ion batteries, but it usually exhibits poor cycling stability because of its huge volume variation during the lithium uptake and release process. A double protection strategy to improve the electrode performance of Ge through the use of Ge@C core-shell nanostructures and reduced graphene oxide (RGO) networks has been developed. The as-synthesized Ge@C/RGO nanocomposite showed excellent cycling performance and rate capability in comparison with Ge@C nanoparticles when used as an anode material for Li ion batteries, which can be attributed to the electronically conductive and elastic RGO networks in addition to the carbon shells and small particle sizes of Ge.

Facile synthesis of silicon nanoparticles inserted into graphene sheets as improved anode materials for lithium-ion batteries.

Silicon nanoparticles have been successfully inserted into graphene sheets via a novel method combining freeze-drying and thermal reduction. The as-obtained Si/graphene nanocomposite exhibits remarkably enhanced cycling performance and rate performance compared with bare Si nanoparticles for lithium-ion batteries.

Construction and repair of highly ordered 2D covalent networks by chemical equilibrium regulation.

The construction of well-ordered 2D covalent networks via the dehydration of di-borate aromatic molecules was successfully realized through introducing a small amount of water into a closed reaction system to regulate the chemical equilibrium.

Chiral hierarchical molecular nanostructures on two-dimensional surface by controllable trinary self-assembly.

The bottom-up fabrication of surface hierarchical nanostructures is of great importance for the development of molecular nanostructures for chiral molecular recognition and enantioselective catalysis. Herein, we report the construction of a series of 2D chiral hierarchical structures by trinary molecular self-assembly with copper phthalocyanine (CuPc), 2,3,7,8,12,13-hexahexyloxy-truxenone (TrO23), and 1,3,5-tris(10-carboxydecyloxy) benzene (TCDB). A series of flower-like chiral hierarchical molecular architectures with increased generations are formed, and the details of these structures are investigated by high resolution scanning tunneling microscopy (STM).