title: A first-cycle coulombic efficiency higher than 100% observed for a Li2MO3 (M = Mo or Ru) electrode.
abstract: The lithiation/de-lithiation behavior of a ternary oxide (Li2MO3, where M = Mo or Ru) is examined. In the first lithiation, the metal oxide (MO2) component in Li2MO3 is lithiated by a conversion reaction to generate nano-sized metal (M) particles and two equivalents of Li2O. As a result, one idling Li2O equivalent is generated from Li2MO3. In the de-lithiation period, three equivalents of Li2O react with M to generate MO3. The first-cycle Coulombic efficiency is theoretically 150% since the initial Li2MO3 takes four Li(+) ions and four electrons per formula unit, whereas the M component is oxidized to MO3 by releasing six Li(+) ions and six electrons. In practice, the first-cycle Coulombic efficiency is less than 150% owing to an irreversible charge consumption for electrolyte decomposition. The as-generated MO3 is lithiated/de-lithiated from the second cycle with excellent cycle performance and rate capability.
authors.affiliation: Department of Chemical and Biological Engineering, Seoul National University, Seoul 151-744 (Korea).
authors.forename: Jihyun
authors.initials: J
authors.lastname: Jang
authors.forename: Youngjin
authors.initials: Y
authors.lastname: Kim
authors.forename: Oh B
authors.initials: OB
authors.lastname: Chae
authors.forename: Taeho
authors.initials: T
authors.lastname: Yoon
authors.forename: Sang-Mo
authors.initials: SM
authors.lastname: Kim
authors.forename: Hyun-seung
authors.initials: HS
authors.lastname: Kim
authors.forename: Hosang
authors.initials: H
authors.lastname: Park
authors.forename: Ji Heon
authors.initials: JH
authors.lastname: Ryu
authors.forename: Seung M
authors.initials: SM
authors.lastname: Oh
keywords: Coulombic efficiency; electrochemistry; energy conversion; lithium-ion batteries; metal oxide electrode