title: Germanium-tin alloy nanocrystals for high-performance lithium ion batteries.
abstract: Germanium-tin (Ge(1-x)Sn(x)) alloy nanocrystals were synthesized using a gas-phase laser photolysis reaction of tetramethyl germanium and tetramethyl tin. A composition tuning was achieved using the partial pressure of precursors in a closed reactor. For x < 0.1, cubic phase alloy nanocrystals were exclusively produced without separation of the tetragonal phase Sn metal. In the range of x = 0.1-0.4, unique Ge(1-x)Sn(x)-Sn alloy-metal hetero-junction nanocrystals were synthesized, where the Sn metal domain becomes dominant with x. Thin graphitic carbon layers usually sheathed the nanocrystals. We investigated the composition-dependent electrochemical properties of these nanocrystals as anode materials of lithium ion batteries. Incorporation of Sn (x = 0.05) significantly increased the capacities (1010 mA h g(-1) after 50 cycles) and rate capabilities, which promises excellent electrode materials for the development of high-performance lithium batteries.
authors.affiliation: Department of Chemistry, Korea University, Jochiwon 339-700, Korea.
authors.forename: Yong Jae
authors.initials: YJ
authors.lastname: Cho
authors.forename: Chang Hyun
authors.initials: CH
authors.lastname: Kim
authors.forename: Hyung Soon
authors.initials: HS
authors.lastname: Im
authors.forename: Yoon
authors.initials: Y
authors.lastname: Myung
authors.forename: Han Sung
authors.initials: HS
authors.lastname: Kim
authors.forename: Seung Hyuk
authors.initials: SH
authors.lastname: Back
authors.forename: Young Rok
authors.initials: YR
authors.lastname: Lim
authors.forename: Chan Su
authors.initials: CS
authors.lastname: Jung
authors.forename: Dong Myung
authors.initials: DM
authors.lastname: Jang
authors.forename: Jeunghee
authors.initials: J
authors.lastname: Park
authors.forename: Sang Hoo
authors.initials: SH
authors.lastname: Lim
authors.forename: Eun Hee
authors.initials: EH
authors.lastname: Cha
authors.forename: Ki Yoon
authors.initials: KY
authors.lastname: Bae
authors.forename: Min Seob
authors.initials: MS
authors.lastname: Song
authors.forename: Won Il
authors.initials: WI
authors.lastname: Cho