Si-SiOx nanoparticles Synthesis for Lithium-Ion Battery Anode Material By Atmospheric Pressure Microwave Plasma

Abstract

Si-SiOx nanoparticles with core-shell structure were synthesized by atmospheric microwave plasma using tetrachloride silicon. Crystalline Si core and amorphous SiOx shell could be controlled by various process conditions. In order to determine the Si-SiOx core-shell ratio for application to anode materials in lithium-ion battery, microstructures and electrochemical properties of synthesized Si-SiOx nanoparticles with various core-shell ratios were investigated. From a result of HR-TEM analysis, there are Si nanoparticles with thickness of 1~3 nm SiOx shell which are only native oxide layer on crystalline Si core. Typical electrochemical behaviour of Si such as high initial reversible capacity and poor retention was observed in those nanoparticles. The shell thickness of Si-SiOx nanoparticles affects the electrochemical properties such as first reversible capacity, retention. For example, nanoparticles with shell thickness of 10 nm exhibited the first reversible capacity of about 1,274 mAh/g and retention at 50th cycle of about 94.8 %. As a result, electrochemical properties could be controlled by the core-shell ratios of Si-SiOx nanoparticles.