A First‐Cycle Coulombic Efficiency Higher than 100 % Observed for a Li2MO3 (M=Mo or Ru) Electrode |
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| Authors: | Jihyun Jang Youngjin Kim Oh B Chae Taeho Yoon Sang‐Mo Kim Hyun‐seung Kim Hosang Park Prof Ji Heon Ryu Prof Seung M Oh |
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| Institution: | 1. Department of Chemical and Biological Engineering, Seoul National University, Seoul 151‐744 (Korea);2. Graduated School of Knowledge‐based Technology and Energy Korea Polytechnic University, Siheung‐si (Korea) |
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| 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. |
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| Keywords: | Coulombic efficiency electrochemistry energy conversion lithium‐ion batteries metal oxide electrode |
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