Synthesis of nanostructured SnO2 for lithium‐ion batteries.

Abstract

This report presents the development of a novel hydrothermal synthesis method to prepare tin dioxide (SnO2) with a unique nanostructure for lithium-ion battery (LIB) application. This project requires the use of scanning electron microscope (SEM) and transmission electron microscope (TEM) to study the structure of the sample. X-ray diffraction (XRD) is employed to determine the purity of SnO2 obtained.

Phase-pure SnO2 nanosheets are synthesized under the following condition: 0.45 g tin dichloride (SnCl2•2H2O) and 0.22 g ammonium fluoride (NH4F) are dissolved in 50 ml distilled water (H2O), and are then heated at 200 °C for 20 hours, giving rise to flower-like crystalline structures with a diameter of approximately 3 um. Different concentration and type of tin precursor and surfactant will result in significant difference in the morphology of SnO2 samples. There is a trend of SnO2 nanosheets aggregating together with increasing SnCl2•2H2O or NH4F. Nevertheless, they will only form flower-like structures if 0.45 g SnCl2•2H2O is to react with 0.22 g NH4F. On the other hand, the effects of temperature and reaction time are considered to be not as significant. Furthermore, if heated at 170 °C for 20 hours with the addition of PVP – 1.3 × 10^6, SnO2 nanosheets are also formed with a different organized structure, where flower-like structures with diameter of approximately 200 nm composed of much smaller nanosheets are obtained.

The electrochemical properties of these SnO2 nanosheets are investigated. Results prove that both samples demonstrate comparably good cyclic retention upon extended cycling up to 50 charge/discharge cycles, and a reversible capacity that is higher than that of graphite can still be delivered at the end of the test. Therefore, the overall battery performance is said to be enhanced.

SnO2 nanosheets can be regarded as a potential LIB anode material due to its enhanced lithium storage properties. Till the present, novel researches using nanotechnology for further LIB technology performance improvement are still on-going. The study of nanotechnology is important as it plays an important role in the modern world, impacting lives of people.