Silicon-based nanowires have been grown from commercial silicon powders under conditions with different oxygen and carbon activities. Nanowires grown in the presence of carbon sources consisted of a crystalline SiC core with an amorphous SiOx shell. The thickness of the SiOx shell decreased as the oxygen concentration in the precursor gases decreased. Nanowires grown in a carbon-free environment consisted of amorphous silicon oxide with a typical composition of SiO1.8. The growth rate of nanowires decreased with decreasing oxygen content in the precursor gases. SiO1.8 nanowires exhibited an initial discharge capacity of ∼1300 mAh g-1 and better stability than those of silicon powders. A vapor-induced solid-liquid-solid (VI-SLS) mechanism is proposed to explain the nanowire growth (including silicon and other metal-based nanowires) from powder sources. In this approach, both a gas source and a solid-powder source are required for nanowire growth. This mechanism is consistent with experimental observations and also can be used to guide the design and growth of other nanowires.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Physical and Theoretical Chemistry
- Electrical and Electronic Engineering