Abstract
The purpose of this study is to synthesize micrometer-sized particles of amorphous and polycrystalline germanium by supercritical thermal decomposition’s method and ultimately draw a comparison between the behavior of these two particles in lithium batteries. To investigate the phase and size of germanium particles and further develop them in lithium batteries, an analysis of germanium particles is conducted with scanning electron microscope, transmission electron microscope,X-ray diffraction and HR-TEM. Moreover, two electrochemical methods are employed so as to compare and contrast the pattern of these two micrometer-sized particles of amorphous and polycrystalline germanium. One is galvanostatic method.The other is cyclic voltammetry (CV).On exploring differences in stability of capacity and differential capacity profiles between amorphous and polycrystalline germanium, a discharge-charge cycling is performed under the galvanostatic method at ambient temperature. In this method, the voltage ranges from 0.01V to 3V at 0.1C discharge -charge rate. Next, a cyclic voltammetry (CV) experiment in different potential is carried out for the analysis of multi-rate discharge-charge capacity between amorphous and polycrystalline germanium micrometer-sized particles. The experiment results indicate that polycrystalline germanium’s cyclic stability(96%) for high rate (1C) 100cycles is better than that of amorphous germanium(55%). In addition, from differential capacity and cyclic voltammetry profiles, we understand that there exist differences between amorphous and polycrystalline germanium in lithiated and de-lithiated potential.