First-Cycle Evolution of Local Structure in Electrochemically Activated Li2MnO3

详细信息    查看全文

• 作者：Jason R. Croy ; Joong Sun Park ; Fulya Dogan ; Christopher S. Johnson ; Baris Key ; Mahalingam Balasubramanian
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：December 23, 2014
• 年：2014
• 卷：26
• 期：24
• 页码：7091-7098
• 全文大小：526K
• ISSN：1520-5002

文摘

X-ray absorption spectroscopy is utilized to determine changes in the local structure of Li₂MnO₃ resulting from electrochemical extraction and insertion of lithium. Specially prepared electrodes allow for a first-cycle charge close to 100% of theoretical, even in crystalline Li₂MnO₃ prepared at 850 掳C. After full delithiation to 鈭? V, the local Mn environments are similar to those of the freshly prepared Li₂MnO₃ electrodes but with increased disorder. On discharge, significant reduction of Mn is observed accompanied by rearrangement of Mn resulting in Jahn鈥揟eller distorted, Mn³⁺ local environments. It is also shown, as expected, that the electrochemical and structural behavior of pure Li₂MnO₃ is markedly different than that observed for the structurally similar Li₂MnO₃ component of lithium- and manganese-rich composite cathodes.