当前位置:
X-MOL 学术
›
J. Mater. Chem. A
›
论文详情
Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
Anionic redox reactions and structural degradation in a cation-disordered rock-salt Li1.2Ti0.4Mn0.4O2 cathode material revealed by solid-state NMR and EPR
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2020-07-14 , DOI: 10.1039/d0ta03358h
Fushan Geng 1, 2, 3, 4, 5 , Bei Hu 1, 2, 3, 4, 5 , Chao Li 1, 2, 3, 4, 5 , Chong Zhao 1, 2, 3, 4, 5 , Olivier Lafon 6, 7, 8, 9, 10 , Julien Trébosc 6, 7, 8, 9, 10 , Jean-Paul Amoureux 6, 7, 8, 9, 10 , Ming Shen 1, 2, 3, 4, 5 , Bingwen Hu 1, 2, 3, 4, 5
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2020-07-14 , DOI: 10.1039/d0ta03358h
Fushan Geng 1, 2, 3, 4, 5 , Bei Hu 1, 2, 3, 4, 5 , Chao Li 1, 2, 3, 4, 5 , Chong Zhao 1, 2, 3, 4, 5 , Olivier Lafon 6, 7, 8, 9, 10 , Julien Trébosc 6, 7, 8, 9, 10 , Jean-Paul Amoureux 6, 7, 8, 9, 10 , Ming Shen 1, 2, 3, 4, 5 , Bingwen Hu 1, 2, 3, 4, 5
Affiliation
![]() |
The burgeoning Li-rich cation-disordered rock-salt (DRX) materials have great potential to serve as the cathodes for rechargeable lithium ion batteries. They generally possess high capacities thanks to the participation of both cationic and anionic redox reactions. However, most DRX materials are subject to a large irreversible capacity loss during the first cycle and an undesirable voltage hysteresis between charge and discharge. In this work, solid-state NMR spectroscopy is employed to resolve the manifold local environments in Li1.2Ti0.4Mn0.4O2 as a model sample, and electron paramagnetic resonance (EPR) spectroscopy is used to investigate its electronic properties. Very broad resonances are observed in the 7Li and 17O NMR spectra. The paramagnetic and diamagnetic Li environments are distinguished, and the loss of the diamagnetic Li signal is observed after the first cycle. The degradation mechanism involved with oxygen loss and transition metal migration is discussed. The formation of the (O2)n− species and electron holes on oxygen at high voltage is suggested by EPR, and the voltage hysteresis is attributed to the difficulty in reducing the stable O–O bonds. These findings may enrich the understanding of DRX materials to better design high-performance DRX cathodes.
中文翻译:
固态NMR和EPR揭示阳离子无序盐盐Li1.2Ti0.4Mn0.4O2正极材料中的阴离子氧化还原反应和结构降解。
新兴的富锂阳离子无序岩石盐(DRX)材料具有巨大的潜力,可以用作可再充电锂离子电池的阴极。由于阳离子和阴离子氧化还原反应的参与,它们通常具有高容量。但是,大多数DRX材料在第一个循环中会遭受很大的不可逆容量损失,并且在充电和放电之间会出现不良的电压滞后现象。在这项工作中,固态NMR光谱用于解析Li 1.2 Ti 0.4 Mn 0.4 O 2作为模型样品中的多个局部环境,并且电子顺磁共振(EPR)光谱用于研究其电子性质。在7中观察到非常广泛的共振Li和17 O NMR谱。区分顺磁性和反磁性Li环境,并在第一个循环后观察到反磁性Li信号的损失。讨论了与氧损失和过渡金属迁移有关的降解机理。的形成(O 2)ñ -对在高电压下氧和电子空穴通过EPR建议,并且电压滞后归因于降低了稳定的O-O键的难度。这些发现可以丰富对DRX材料的理解,从而更好地设计高性能DRX阴极。
更新日期:2020-08-18
中文翻译:
![](https://scdn.x-mol.com/jcss/images/paperTranslation.png)
固态NMR和EPR揭示阳离子无序盐盐Li1.2Ti0.4Mn0.4O2正极材料中的阴离子氧化还原反应和结构降解。
新兴的富锂阳离子无序岩石盐(DRX)材料具有巨大的潜力,可以用作可再充电锂离子电池的阴极。由于阳离子和阴离子氧化还原反应的参与,它们通常具有高容量。但是,大多数DRX材料在第一个循环中会遭受很大的不可逆容量损失,并且在充电和放电之间会出现不良的电压滞后现象。在这项工作中,固态NMR光谱用于解析Li 1.2 Ti 0.4 Mn 0.4 O 2作为模型样品中的多个局部环境,并且电子顺磁共振(EPR)光谱用于研究其电子性质。在7中观察到非常广泛的共振Li和17 O NMR谱。区分顺磁性和反磁性Li环境,并在第一个循环后观察到反磁性Li信号的损失。讨论了与氧损失和过渡金属迁移有关的降解机理。的形成(O 2)ñ -对在高电压下氧和电子空穴通过EPR建议,并且电压滞后归因于降低了稳定的O-O键的难度。这些发现可以丰富对DRX材料的理解,从而更好地设计高性能DRX阴极。