Carbon-coated SnO2 riveted on a reduced graphene oxide composite (C@SnO2/RGO) as an anode material for lithium-ion batteries.

The research on graphene-based anode materials for high-performance lithium-ion batteries (LIBs) has been prevalent in recent years. In the present work, carbon-coated SnO2 riveted on a reduced graphene oxide sheet composite (C@SnO2/RGO) was fabricated using GO solution, SnCl4, and glucose via a hydrothermal method after heat treatment. When the composite was exploited as an anode material for LIBs, the electrodes were found to exhibit a stable reversible discharge capacity of 843 mA h g-1 at 100 mA g-1 after 100 cycles with 99.5% coulombic efficiency (CE), and a specific capacity of 485 mA h g-1 at 1000 mA g-1 after 200 cycles; these values were higher than those for a sample without glucose (SnO2/RGO) and a pure SnO2 sample. The favourable electrochemical performances of the C@SnO2/RGO electrodes may be attributed to the special double-carbon structure of the composite, which can effectively suppress the volume expansion of SnO2 nanoparticles and facilitate the transfer rates of Li+ and electrons during the charge/discharge process.

Synthesis of MnCO3/Multiwalled Carbon Nanotube Composite as Anode Material for Lithium-Ion Batteries.

A MnCO3 /Multiwalled carbon nanotube (MnCO3/MWCNT) composite has been successfully fabricated by an in-suit hydrothermal method. When the MnCO3/MWCNT composite is applied as anode materials in lithium-ion batteries (LIBs), the electrodes exhibit a reversible capacity of 645 mA h g-1 at 100 mA g-1 after 80 cycles, reaching an initial coulombic efficiency (CE) of up to 60.6%. Furthermore, the as-prepared MnCO3/MWCNT composite displays more excellent rate performances than the pure multiwalled carbon nanotube (MWCNT) and pure MnCO3 particles. The reason is that the MnCO3 particles can be effectively connected by the MWCNT, thus enhancing the electrochemical performance of the MnCO3/MWCNT composite.

Preparation of novel two-stage structure MnO micrometer particles as lithium-ion battery anode materials.

MnO micrometer particles with a two-stage structure (composed of mass nanoparticles) were produced via a one-step hydrothermal method using histidine and potassium permanganate (KMnO4) as reagents, with subsequent calcination in a nitrogen (N2) atmosphere. When the MnO micrometer particles were utilized in lithium-ion batteries (LIBs) as anode materials, the electrode showed a high reversible specific capacity of 747 mA h g-1 at 100 mA g-1 after 100 cycles, meanwhile, the electrode presented excellent rate capability at various current densities from 100 to 2000 mA g-1 (∼203 mA h g-1 at 2000 mA g-1). This study developed a new approach to prepare two-stage structure micrometer MnO particles and the sample can be a promising anode material for lithium-ion batteries.

Theoretical design of a new family of two-dimensional topological insulators.

A new family of two-dimensional topological insulator, hydrogenated monolayer Pb2XY (X = Ga/In, Y = Sb/Bi), has been predicted using first-principles density functional theory. The electronic bulk band gap of the proposed systems can be induced in the presence of a spin-orbit coupling effect and its highest value (0.25 eV) was observed in the hydrogenated monolayer Pb2GaBi, which is suitable for practical application. Our simulation study points out that the nanoribbons derived from this new family harbor gapless edge channels. The non-trivial topological nature was further confirmed by calculating the Z2 topological invariant. These novel systems provide a new platform for topological phenomena observation and spintronic applications.

Enhanced antimicrobial activities of silver-nanoparticle-decorated reduced graphene nanocomposites against oral pathogens.

As a means of capitalizing on the synergistic properties between reduced graphene nanosheets (R-GNs) and silver nanoparticles (AgNPs), an efficient and convenient chemical reduction method was used to prepare silver-nanoparticle-decorated reduced graphene nanocomposites (R-GNs/Ag). The products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy, which confirmed the loading of well-dispersed silver nanoparticles on reduced graphene sheets. Their antimicrobial activities against oral pathogens such as Candida albicans, Lactobacillus acidophilus, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans were investigated by MIC determination, the counting of colony-forming units (CFU), agar diffusion tests, and growth curve observation. Compared with pure R-GNs and AgNPs, R-GNs/Ag composites exhibited enhanced antimicrobial properties owing to highly dispersed AgNPs on R-GNs.