Hollow Silicon Nanostructures via the Kirkendall Effect.
The Kirkendall effect is a simple, novel phenomenon that may be applied for the synthesis of hollow nanostructures with designed pore structures and chemical composition. We demonstrate the use of the Kirkendall effect for silicon (Si) and germanium (Ge) nanowires (NWs) and nanoparticles (NPs) via introduction of nanoscale surface layers of SiO2 and GeO2, respectively. Depending on the reaction time, Si and Ge atoms gradually diffuse outward through the oxide layers, with pore formation in the nanostructural cores. Through the Kirkendall effect, NWs and NPs were transformed into nanotubes (NTs) and hollow NPs, respectively. The mechanism of the Kirkendall effect was studied via quantum molecular dynamics calculations. The hollow products demonstrated better electrochemical performance than their solid counterparts because the pores developed in the nanostructures resulted in lower external pressures during lithiation.
School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , 689-798, Ulsan, South Korea.
Yoonkook
Y
Son
School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , 689-798, Ulsan, South Korea.
Yeonguk
Y
Son
Min
M
Choi
School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , 689-798, Ulsan, South Korea.
Minseong
M
Ko
School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , 689-798, Ulsan, South Korea.
Sujong
S
Chae
Noejung
N
Park
School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , 689-798, Ulsan, South Korea.
Jaephil
J
Cho
Kirkendall effect; hollow nanostructure; lithium ion batteries; self-organization; silicon