Cathode having high rate performance for a secondary Li-ion cell surface-modified by aluminum oxide nanoparticles

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• 作者：Toyoki Okumura ; Tomokazu Fukutsuka ; Yoshiharu Uchimoto ; Koji Amezawa ; Shota Kobayashi
• 关键词：High power density ; Surface modification ; LiMn₂O₄ ; Electrode/electrolyte interface
• 刊名：Journal of Power Sources
• 出版年：2009
• 出版时间：1 April 2009
• 年：2009
• 卷：189
• 期：1
• 页码：471-475
• 全文大小：468 K

文摘

In order to enhance the electrochemical properties, the spinel LiMn₂O₄ electrode surface was modified with amorphous Al₂O₃ nanoparticle as heterogeneous phase. LiMn₂O₄ was in preparation based on a conventional solid-state reaction. The LiMn₂O₄ procedure was soaked in aluminum tri 2-propoxide solution. The LiMn₂O₄ whose surface was modified by aluminum oxide was obtained through the heat treatment at 400 °C for 4 h. The Al₂O₃-modified LiMn₂O₄ electrode exhibits a capacity higher than that of the unmodified LiMn₂O₄ electrode. On the other hand, no variation was shown with open circuit potential and apparent chemical diffusion coefficient of Li ion for LiMn₂O₄ before and after the surface modification. The charge-transfer resistance of Al₂O₃-modified LiMn₂O₄ decreased significantly in comparison with the unmodified LiMn₂O₄. The improved charge-transfer kinetics was largely attributed to Al₂O₃ which plays an important role of increasing the chemical potential at the electrode/electrolyte interface.