High-capacity phase formation by surface modification of Li₃PO₄ on nanosized Li₂RuO₃ electrode for lithium batteries

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• 作者：Yueming Zheng^a ; ^b ; Sou Taminato^b ; Youlong Xu^a ; Kota Suzuki^b ; KyungSu Kim^b ; Masaaki Hirayama^b ; ^{hirayama@echem.titech.ac.jp} ; Ryoji Kanno^b
• 关键词：Lithium ruthenium oxide ; Lithium phosphate ; Epitaxial film model electrodes ; Surface structure
• 刊名：Journal of Power Sources
• 出版年：2012
• 期刊代码：58_03787753
• 类别：ce
• 出版时间：15 June, 2012
• 卷：208
• 期：Complete
• 页码：447-451
• 文件大小：458 K

摘要

Effects of modifying the surface of lithium excess layered rock-salt type electrodes by Li₃PO₄ is investigated using epitaxial Li₂RuO₃ model electrodes. A 3.6-nm-thick amorphous Li₃PO₄ layer is deposited on a 25.5-nm-thick Li₂RuO₃ film by pulsed laser deposition. X-ray absorption near edge structure reveals that the modified Li₂RuO₃ surface had different electronic states of Ru from the unmodified Li₂RuO₃ surface, indicating that Li₃PO₄ deposition changes the structure of the Li₂RuO₃ surface. Li₃PO₄-modified Li₂RuO₃ has a much higher first discharge capacity (296 mAh g^鈭?) between 2.8 and 4.2 V than unmodified Li₂RuO₃ (190 mAh g^鈭?). The modified and unmodified Li₂RuO₃ have irreversible capacities in the first charge/discharge process of 22 and 148 mAh g^鈭?, respectively. The surface modification induced by Li₃PO₄ deposition enhances the structural stability of the Li₂RuO₃ surface during the initial charging process.