摘要
Solid-state 7Li NMR spectroscopy revealed different Ni/Co distributions in an inverse spinel structure of LiNixCo1-VO4 cathode materials prepared by either a high-temperature solid-state reaction method (abbreviated as the HT method) or a low-temperature solution co-precipitation method (abbreviated as the LT method). Solid-state 7Li NMR measurements confirmed that the lithium nuclear spin was dominated by a chemical shift anisotropy (CSA) interaction compounded with a small second-order quadrupolar interaction. Ni/Co distribution and inhomogeneity of chemical shift tensors (δCSA and ηCSA constants) associated with crystalline defects are accountable for the variation in spread of the MAS spinning side-band manifolds between nickel uptake and preparation methods. The NMR study also revealed that the HT method yielded broader Ni/Co distributions with greater lithium defects, while the LT method gave much more homogeneous Ni/Co distributions with smaller defects. The NMR results were consistent with XRD data that showed a gradual expansion in the unit-cell lattice with increasing Co content. All cells suffered a large irreversible loss in overall capacity in the first cycle and became stable in terms of cycle efficiency during later cycling. We have found that LiNixCo1-xVO4 cathode materials prepared by the LT method with more homogeneous Ni/Co distribution and smaller crystalline defects offer a small advantage in capacity over the HT method.
原文 | ???core.languages.en_GB??? |
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頁(從 - 到) | 95-102 |
頁數 | 8 |
期刊 | Journal of Power Sources |
卷 | 90 |
發行號 | 1 |
DOIs | |
出版狀態 | 已出版 - 9月 2000 |
事件 | The 1999 International Symposium on Rechargeable - Kyoto, Jpn 持續時間: 14 11月 1999 → 16 11月 1999 |