Synthesis of Tetrahedral LiFeO2 and Its Behavior as a Cathode in Rechargeable Lithium Batteries

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• 作者：A. Robert Armstrong ; Daniel W. Tee ; Fabio La Mantia ; Petr Nov&aacute ; k ; Peter G. Bruce
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：March 19, 2008
• 年：2008
• 卷：130
• 期：11
• 页码：3554 - 3559
• 全文大小：428K
• 年卷期：v.130,no.11(March 19, 2008)
• ISSN：1520-5126

文摘

Synthesis and structural characterization of the first LiFeO₂ compound with tetrahedrallycoordinated Fe³⁺ is reported. When used as a positive intercalation electrode in a lithium cell, it can storecharge of up to 120 mAhg^-1 at a rate of 100 mAg^-1. However, it converts to the defect spinel LiFe₅O₈ oncycling. By combining results from powder X-ray diffraction, differential electrochemical mass spectrometry,electrochemical cycling, and TG-MS, it is shown that such conversion, which involved oxygen loss, is notassociated with direct O₂ gas evolution but instead reaction with the electrolyte. We suggest that intercalation/deintercalation is accompanied by the exchange of Li⁺ by H⁺ in the material and subsequent loss of H₂O,thus converting LiFeO₂ to the defect spinel LiFe₅O₈ on cycling.