High throughput production of nanocomposite SiO x powders by plasma spray physical vapor deposition for negative electrode of lithium ion batteries

• Main Authors: Keiichiro Homma, Makoto Kambara, Toyonobu Yoshida
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2014-04-01
• Series: Science and Technology of Advanced Materials
• Online Access: http://dx.doi.org/10.1088/1468-6996/15/2/025006

Nanocomposite Si/SiO x powders were produced by plasma spray physical vapor deposition (PS-PVD) at a material throughput of 480 g h−1. The powders are fundamentally an aggregate of primary ~20 nm particles, which are composed of a crystalline Si core and SiO x shell structure. This is made possible by complete evaporation of raw SiO powders and subsequent rapid condensation of high temperature SiO x vapors, followed by disproportionation reaction of nucleated SiO x nanoparticles. When CH4 was additionally introduced to the PS-PVD, the volume of the core Si increases while reducing potentially the SiO x shell thickness as a result of the enhanced SiO reduction, although an unfavorable SiC phase emerges when the C/Si molar ratio is greater than 1. As a result of the increased amount of Si active material and reduced source for irreversible capacity, half-cell batteries made of PS-PVD powders with C/Si = 0.25 have exhibited improved initial efficiency and maintenance of capacity as high as 1000 mAh g−1 after 100 cycles at the same time.