Synthesis of monodispersed SnO2@C composite hollow spheres for lithium ion battery anode applications

RSC Publishing: Tin oxides and carbon (SnO2@C) composite hollow spheres with improved electrochemical performance were fabricated via a facile hard template route. Monodispersed polystyrene (PS) spheres were synthesized and utilized as hard templates. A thin and porous layer of SnO2 nanoparticles was deposited on a PS surface using a well controlled sol–gel method, so that the morphology of the active SnO2 layer could be optimized for a better electrochemical performance.

Furthermore, a continuous carbon coating layer was incorporated with an aim of enhancing the conductivity, holding the structure integrity, and thus improving the cycling performance of the anode material.

With such a carefully designed nanostructure, the as-prepared SnO2@C composite hollow spheres possessed the desired features for a good electrode material. After 50 successive cycles, SnO2@C anode was able to deliver a capacity of 495 mAh g−1 at a scan rate of 100 mA g−1.

Synthesis and characterization of low temperature Sn nanoparticles for the fabrication of highly conductive ink

IOP Science: To fabricate a low cost, highly conductive ink for inkjet printing, we synthesized a gram scale of uniformly sized Sn nanoparticles by using a modified polyol process and observed a significant size-dependent melting temperature depression from 234.1 'C for bulk Sn to 177.3 'C for 11.3 nm Sn nanoparticles.

A 20 wt% of Sn nanoparticles was dispersed in the 50% ethylene glycol: 50% isopropyl alcohol mixed solvent for the appropriate viscosity (11.6 cP) and surface tension (32 dyn cm − 1). To improve the electrical property, we applied the surface treatments of hydrogen reduction and plasma ashing.

The two treatments had the effect of diminishing the sheet resistance from 1kΩ/sq to 50Ω/sq. In addition, conductive patterns (1cm x 1cm) were successfully drawn on the Si wafer using an inkjet printing instrument with conductive Sn ink. The maximum resistivity for an hour of sintering at 250 'C was 64.24Ωcm, which is six times higher than the bulk Sn resistivity (10.1Ωcm).