Chemical and Electrochemical Lithiation of LiVOPO4 Cathodes for Lithium-Ion Batteries

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• 作者：Katharine L. Harrison ; Craig A. Bridges ; Carlo U. Segre ; C. Daniel Varnado Jr. ; Danielle Applestone ; Christopher W. Bielawski ; Mariappan Parans Paranthaman ; Arumugam Manthiram
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：June 24, 2014
• 年：2014
• 卷：26
• 期：12
• 页码：3849-3861
• 全文大小：716K
• ISSN：1520-5002

文摘

The theoretical capacity of LiVOPO₄ could be increased from 159 to 318 mAh/g with the insertion of a second Li⁺ ion into the lattice to form Li₂VOPO₄, significantly enhancing the energy density of lithium-ion batteries. The phase changes accompanying the second Li⁺ insertion into 伪-LiVOPO₄ and 尾-LiVOPO₄ are presented here at various degrees of lithiation, employing both electrochemical and chemical lithiation. Inductively coupled plasma, X-ray absorption spectroscopy, and Fourier transform infrared spectroscopy measurements indicate that a composition of Li₂VOPO₄ can be realized with an oxidation state of V³⁺ by the chemical lithiation process. The accompanying structural changes are evidenced by X-ray and neutron powder diffraction. Spectroscopic and diffraction data collected with the chemically lithiated samples as well as diffraction data on the electrochemically lithiated samples reveal that a significant amount of lithium can be inserted into 伪-LiVOPO₄ before a phase change occurs. In contrast, lithiation of 尾-LiVOPO₄ is more consistent with the formation of a two-phase mixture throughout most of the lithiation range. The phases observed with the ambient-temperature lithiation processes presented here are significantly different from those reported in the literature.