title: Si/Ge double-layered nanotube array as a lithium ion battery anode.
abstract: Problems related to tremendous volume changes associated with cycling and the low electron conductivity and ion diffusivity of Si represent major obstacles to its use in high-capacity anodes for lithium ion batteries. We have developed a group IVA based nanotube heterostructure array, consisting of a high-capacity Si inner layer and a highly conductive Ge outer layer, to yield both favorable mechanics and kinetics in battery applications. This type of Si/Ge double-layered nanotube array electrode exhibits improved electrochemical performances over the analogous homogeneous Si system, including stable capacity retention (85% after 50 cycles) and doubled capacity at a 3C rate. These results stem from reduced maximum hoop strain in the nanotubes, supported by theoretical mechanics modeling, and lowered activation energy barrier for Li diffusion. This electrode technology creates opportunities in the development of group IVA nanotube heterostructures for next generation lithium ion batteries.
authors.affiliation: Department of Materials Science Engineering, Hanyang University, Seoul 133-791, Korea.
authors.forename: Taeseup
authors.initials: T
authors.lastname: Song
authors.forename: Huanyu
authors.initials: H
authors.lastname: Cheng
authors.forename: Heechae
authors.initials: H
authors.lastname: Choi
authors.forename: Jin-Hyon
authors.initials: JH
authors.lastname: Lee
authors.forename: Hyungkyu
authors.initials: H
authors.lastname: Han
authors.forename: Dong Hyun
authors.initials: DH
authors.lastname: Lee
authors.forename: Dong Su
authors.initials: DS
authors.lastname: Yoo
authors.forename: Moon-Seok
authors.initials: MS
authors.lastname: Kwon
authors.forename: Jae-Man
authors.initials: JM
authors.lastname: Choi
authors.forename: Seok Gwang
authors.initials: SG
authors.lastname: Doo
authors.forename: Hyuk
authors.initials: H
authors.lastname: Chang
authors.forename: Jianliang
authors.initials: J
authors.lastname: Xiao
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Huang
authors.forename: Won Il
authors.initials: WI
authors.lastname: Park
authors.forename: Yong-Chae
authors.initials: YC
authors.lastname: Chung
authors.forename: Hansu
authors.initials: H
authors.lastname: Kim
authors.forename: John A
authors.initials: JA
authors.lastname: Rogers
authors.forename: Ungyu
authors.initials: U
authors.lastname: Paik
mesh_terms: D003460:Crystallization / Q000379:methods*; D011211:Electric Power Supplies; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005857:Germanium / Q000737:chemistry*; D007477:Ions; D008094:Lithium / Q000737:chemistry*; D008422:Materials Testing; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012825:Silicon / Q000737:chemistry*
chemical_list: D007477:Ions; D005857:Germanium; D008094:Lithium; D012825:Silicon