Article

In situ X-ray diffraction studies of (de)lithiation mechanism in silicon nanowire anodes.

Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
ACS Nano (impact factor: 10.77). 05/2012; 6(6):5465-73. DOI:10.1021/nn301339g pp.5465-73
Source: PubMed

ABSTRACT Silicon is a promising anode material for Li-ion batteries due to its high theoretical specific capacity. From previous work, silicon nanowires (SiNWs) are known to undergo amorphorization during lithiation, and no crystalline Li-Si product has been observed. In this work, we use an X-ray transparent battery cell to perform in situ synchrotron X-ray diffraction on SiNWs in real time during electrochemical cycling. At deep lithiation voltages the known metastable Li(15)Si(4) phase forms, and we show that avoiding the formation of this phase, by modifying the SiNW growth temperature, improves the cycling performance of SiNW anodes. Our results provide insight on the (de)lithiation mechanism and a correlation between phase evolution and electrochemical performance for SiNW anodes.

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Keywords

amorphorization
 
crystalline Li-Si product
 
electrochemical cycling
 
electrochemical performance
 
phase evolution
 
promising anode material
 
Silicon
 
silicon nanowires
 
SiNW anodes
 
SiNW growth temperature
 
SiNWs
 
theoretical specific capacity
 
X-ray transparent battery cell
 

Sumohan Misra