A First-Cycle Coulombic Efficiency Higher than 100% Observed for a Li sub(2)MO sub(3) (M=Mo or Ru) Electrode

• Published in: Angewandte Chemie Vol. 126; no. 40; pp. 10830 - 10833
• Main Authors: Jang, Jihyun, Kim, Youngjin, Chae, Oh B, Yoon, Taeho, Kim, Sang-Mo, Kim, Hyun-seung, Park, Hosang, Ryu, Ji Heon, Oh, Seung M
• Format: Journal Article
• Language: English
• Published: 01.09.2014
• Subjects: Computational efficiency; Computing time; Consumption; Conversion; Electrodes; Electrolytes; Equivalence; Metal oxides; Oxides
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.201404510

The lithiation/de-lithiation behavior of a ternary oxide (Li sub(2)MO sub(3), where M=Mo or Ru) is examined. In the first lithiation, the metal oxide (MO sub(2)) component in Li sub(2)MO sub(3) is lithiated by a conversion reaction to generate nano-sized metal (M) particles and two equivalents of Li sub(2)O. As a result, one idling Li sub(2)O equivalent is generated from Li sub(2)MO sub(3). In the de-lithiation period, three equivalents of Li sub(2)O react with M to generate MO sub(3). The first-cycle Coulombic efficiency is theoretically 150% since the initial Li sub(2)MO sub(3) takes four Li super(+) ions and four electrons per formula unit, whereas the M component is oxidized to MO sub(3) by releasing six Li super(+) 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 MO sub(3) is lithiated/de-lithiated from the second cycle with excellent cycle performance and rate capability.Original Abstract: Mr. 150%: Nanometergrose Metallkomponenten (Mo oder Ru; M), die aus Li sub(2)MO sub(3) unter Verbrauch von vier Li super(+)-Ionen und vier Elektronen entstehen, reagieren mit Li sub(2)O als physikalisches Gemisch. Fuer die Reaktion mit Li sub(2)O im ersten Zyklus ergibt sich theoretisch ein Coulomb-Wirkungsgrad (CE) von 150%, da die Metallkomponente unter Freisetzung von sechs Li super(+)-Ionen und sechs Elektronen pro Formeleinheit zu MO sub(3) oxidiert wird.