2016-Sustainable Industrial Processing Summit
SIPS 2016 Volume 10: Battery, Recycling, Environmental, Mining
| Editors: | Kongoli F, Kumar V, Aifantis K, Pagnanelli F |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2016 |
| Pages: | 220 pages |
| ISBN: | 978-1-987820-54-6 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
CD shopping page
Understanding the anomalously high capacity of electrode materials for Li-ion batteries
Won-Sub Yoon1;1SUNGKYUNGKWAN UNIVERSITY, Suwon, Korea (Republic of [South] Korea);
Type of Paper: Plenary
Id Paper: 487
Topic: 14
Abstract:
The reaction mechanism of a high capacity lithium- and manganese-rich metal oxide has been investigated. High-resolution synchrotron X-ray powder diffraction (HRPD) and X-ray absorption spectroscopy (XAS) were used, respectively, to evaluate the electrochemical charge and discharge reactions in terms of local and bulk structural changes, and variations in the oxidation states of the transition metal ions. Ni K-edge XAS data indicate the participation of nickel in reversible redox reactions, whereas Mn K-edge absorption spectra show that the manganese ions do not participate in the electrochemical reactions. Rietveld refinements of the oxygen occupancy during charge and discharge provide evidence of reversible oxygen contribution by the host structure; this unique oxygen participation is likely the main reason for the anomalously high capacity of these electrodes. The HRPD data also show that during the early cycles, characteristic peaks of the Li2MnO3 component disappear when charged to 4.7 V, but reappear on discharge to 2.5 V, consistent with a reversible lithium and oxygen extraction process. The results provide new insights into the charge compensation mechanisms that occur when high capacity, lithium- and manganese-rich electrode materials are electrochemically cycled � a topic that is currently being hotly debated in the literature. The reaction mechanism of abnormal capacity for anode materials will be also discussed in the meeting.