Z. Naturforsch. 68a, 73 – 78
Observation of Lithium Isotope Effects Accompanying Electrochemical Release from Lithium Cobalt Oxide
1 Faculty of Science and Technology, Sophia University, 7-1 Kioicho, Chiyodaku, Tokyo 102-8554, Japan
2 Samsung Yokohama Research Institute Co., Ltd., 2-7 Sugasawa-cho, Tsurumiku, Yokohama, Kanagawa 230-0027, Japan
Received August 23, 2012 / published online February 15, 2013
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Change in the lithium isotope composition in a lithium cobalt oxide (LiCoO2) cathode for lithium ion secondary batteries accompanying the electrochemical lithium release from the cathode into an organic electrolyte solution was observed. The 7Li/6Li isotopic ratios of the electrodes after the release of 37.2 to 55.4 % lithium were 1.018 to 1.033 times smaller than that before the release. This means that the heavier isotope, 7Li, is preferentially transferred to the electrolyte solution.
Key words: Lithium Isotope Effects; Lithium Cobalt Oxide; Charge Reaction; Lithium Ion Secondary Batteries; Separation Factor.