title: ZnO decorated germanium nanoparticles as anode materials in Li-ion batteries.
abstract: Germanium exhibits high charge capacity and high lithium diffusivity, both are the key requirements for electrode materials in high performance lithium ion batteries (LIBs). However, high volume expansion and segregation from the electrode during charge-discharge cycling have limited use of germanium in LIBs. Here, we demonstrate that ZnO decorated Ge nanoparticles (Ge@ZnO NPs) can overcome these limitations of Ge as an LIB anode material. We produced Ge NPs at high rates by laser pyrolysis of GeH4, then coated them with solution phase synthesized ZnO NPs. Half-cell tests revealed dramatically enhanced cycling stability and higher rate capability of Ge@ZnO NPs compared to Ge NPs. Enhancements arise from the core-shell structure of Ge@ZnO NPs as well as production of metallic Zn from the ZnO layer. These findings not only demonstrate a new surface treatment for Ge NPs, but also provide a new opportunity for development of high-rate LIBs.
authors.affiliation: School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919,  Republic of Korea.
authors.forename: Tae-Hee
authors.initials: TH
authors.lastname: Kim
authors.forename: Song Yi
authors.initials: SY
authors.lastname: Park
authors.forename: Tack Ho
authors.initials: TH
authors.lastname: Lee
authors.forename: Jaeki
authors.initials: J
authors.lastname: Jeong
authors.forename: Dong Suk
authors.initials: DS
authors.lastname: Kim
authors.forename: Mark T
authors.initials: MT
authors.lastname: Swihart
authors.forename: Hyun-Kon
authors.initials: HK
authors.lastname: Song
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Seongbeom
authors.initials: S
authors.lastname: Kim