Tracking Formation and Decomposition of Abacus-Ball-Shaped Lithium Peroxides in Li鈥揙2 Cells

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• 作者：Wugang Fan ; Zhonghui Cui ; Xiangxin Guo
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：February 14, 2013
• 年：2013
• 卷：117
• 期：6
• 页码：2623-2627
• 全文大小：424K
• 年卷期：v.117,no.6(February 14, 2013)
• ISSN：1932-7455

文摘

Study of formation and decomposition of Li₂O₂ during operations of Li鈥揙₂ cells is essential for understanding the reaction mechanism and finding solutions to improve the cell performance. Using vertically aligned carbon nanotubes (VACNTs) directly grown on stainless steel meshes as the cathodes in the Li鈥揙₂ cells with dimethoxyethane (DME) electrolytes, nucleation, growth, and decomposition processes of the Li₂O₂ in the first cycle are clearly visualized. Through cycles with the controlled discharge and charge capacities, the abacus-ball-shaped Li₂O₂ and the rust-like carbonates simultaneously formed around the VACNTs are further identified. It is indicated that the increasing coverage of carbonates on the cathode surface suppresses the formation of Li₂O₂, which maintains the shape of abacus ball. When the VACNT surfaces are predominantly covered by the carbonates, the cells tend to terminate.