S. Seki, Yasutaka Ohno, H. Miyashiro
Jun 1, 2008
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Influential Citations
83
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Quality indicators
Journal
Journal of The Electrochemical Society
Abstract
To determine the properties of the quaternary ammonium cation room-temperature ionic liquid [N,N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium bis (trifluoromethylsulfonyl) amide (DEMETFSA)] used in lithium secondary battery electrolytes, the lithium ionic transport properties of electrolytes, the characteristics of the interface of a LiCoO 2 cathode and a metallic lithium anode, and battery performance were widely investigated. A DEMETFSA-LiTFSA binary electrolyte showed high chemical stability with lithium metal electrode and a relatively high lithium cationic transport number (0.13), as determined by electrochemical measurements. The prepared [LiCoO 2 cathode|DEMETFSA-LiTFSA binary electrolyte|lithium metal anode] cell showed sufficient charge/discharge reversibility over 100 cycles (voltage range, 4.2-3.0 V). Moreover, the reversibility of capacities and coulombic efficiencies degraded with increasing upper cutoff voltage owing to cathode/electrolyte interfacial degradation, which were analyzed in detail by impedance measurements.