Arrays of sealed silicon nanotubes as anodes for lithium ion batteries.
Silicon is a promising candidate for electrodes in lithium ion batteries due to its large theoretical energy density. Poor capacity retention, caused by pulverization of Si during cycling, frustrates its practical application. We have developed a nanostructured form of silicon, consisting of arrays of sealed, tubular geometries that is capable of accommodating large volume changes associated with lithiation in battery applications. Such electrodes exhibit high initial Coulombic efficiencies (i.e., >85%) and stable capacity-retention (>80% after 50 cycles), due to an unusual, underlying mechanics that is dominated by free surfaces. This physics is manifested by a strongly anisotropic expansion in which 400% volumetric increases are accomplished with only relatively small (<35%) changes in the axial dimension. These experimental results and associated theoretical mechanics models demonstrate the extent to which nanoscale engineering of electrode geometry can be used to advantage in the design of rechargeable batteries with highly reversible capacity and long-term cycle stability.
Song
Taeseup
T
Division of Materials Science Engineering, Hanyang University, Seoul, Korea.
Xia
Jianliang
J
Lee
Jin-Hyon
JH
Lee
Dong Hyun
DH
Kwon
Moon-Seok
MS
Choi
Jae-Man
JM
Wu
Jian
J
Doo
Seok Kwang
SK
Chang
Hyuk
H
Park
Won Il
WI
Zang
Dong Sik
DS
Kim
Hansu
H
Huang
Yonggang
Y
Hwang
Keh-Chih
KC
Rogers
John A
JA
Paik
Ungyu
U
D003460:Crystallization / Q000379:methods; D011211:Electric Power Supplies; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008094:Lithium / Q000737:chemistry*; D008422:Materials Testing; D036103:Nanotechnology / Q000295:instrumentation*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012825:Silicon / Q000737:chemistry*
D008094:Lithium; D012825:Silicon