Yunxiao Zheng

Preparation and Li-storage properties of SnSb/graphene hybrid nanostructure by a facile one-step solvothermal route

A SnSb nanocrystal/graphene hybrid nanocomposite was synthesized by a facile one-step solvothermal route using graphite oxide, SnCl2.2H2O and SbCl3 as the starting materials, absolute ethanol as the solvent, and NaBH4 as the reductant. The formation of SnSb alloy and the reduction of the graphene oxide occur simultaneously. SnSb nanoparticles with a size of 30–40 nm were uniformly anchored and confined by the graphene sheets, forming a unique SnSb/graphene hybrid nanostructure. The electrostatic attraction between the positively charged ions (Sn2+ and Sb3+) and the negatively charged graphene oxide plays an important role in the uniform distribution of the SnSb particles on the graphene sheets. The electrochemical Li-storage properties of the nanocomposite were investigated as a potential high-capacity anode material for Li-ion batteries. The results show that the nanocomposite exhibits an obvious enhanced Li-storage performance compared with bare SnSb. The improvement of the electrochemical performance could be attributed to the formation of two-dimensional conductive networks, homogeneous dispersion and confinement of SnSb nanoparticles and the enhanced wetting of active material with the electrolyte for increased specific surface area by the introduction of graphene into SnSb nanoparticles. Li-ion chemical diffusion coefficient and ac impedance were measured to understand the underlying mechanism for the improved electrochemical performance.

One-pot In-situ Synthesis of Sn/Carbon-fibers Nanocomposite by Chemical Vapor Deposition and Its Li-storage Properties

Sn/carbon-fibers (CFs) nanocomposite has been prepared by chemical vapor deposition with in-situ catalytic growth of CFs. The nanocomposite has been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and Raman spectrum. The electrochemical performance of the nanocomposite has been investigated by galvanostatic cycling and cyclic voltammetry (CV). It has been found that a three-dimensional conductive network forms by the interconnected CFs, which offers conductive channels for the Sn nanoparticles. The nanocomposite gives a first charge capacity of 385 mAh·g −1 and exhibits an improved cycling stability than bare Sn.

RAPID SYNTHESIS OF CoSb3/GRAPHENE NANOCOMPOSITES BY ONE-POT SOLVOTHERMAL ROUTE AND THEIR ELECTROCHEMICAL PROPERTIES

A facile synthetic approach for CoSb3/graphene nanocomposite has been developed in this work. By adjusting Co/Sb molar ratio, reaction temperature, and reaction time, we found that nanocrystalline CoSb3 (5–10 nm) can form at a low temperature of 180°C and a short time of only 1 h via a one-pot solvothermal route. At the same time, graphite oxide can be reduced to graphene with uniformly loaded CoSb3 nanoparticles. The composites have been characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The nanocomposite shows improved cycling stability compared to bare CoSb3.