在氧化阴极中,区分散装氧化还原与近表面降解
Lijin An1, Jack E N Swallow1, Peixi Cong1
1Department of Materials, University of Oxford Parks Road Oxford OX1 3PH UK robert.weatherup@materials.ox.ac.uk.
概括
富含的分层氧化物阴极通过Ni-O重杂化显示大量氧化还原,而不是氧化还原. 捕获的氧气表明表面降解和Ni减少,这对电池周期寿命至关重要.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 电池技术 电池技术
背景情况:
- 富含的分层氧化物为电池提供高能量密度.
- 这些材料的电荷补偿机制和降解仍然不清楚.
- 在高电荷状态下,在LiNiO2中观察到被困的分子氧 (O2).
研究的目的:
- 阐明 LiNiO2.2 中的负载补偿机制.
- 为了确定分子氧在LiNiO2.2.中的作用.
- 了解降解过程限制Ni丰富阴极的循环寿命.
主要方法:
- 在现场/操作的X射线吸收光谱 (XAS) 来探测Ni的氧化状态.
- 用于表面分析的X射线光电子光谱 (XPS).
- 传输电子显微镜 (TEM) 用于结构特征.
主要成果:
- 在LiNiO2中的散装氧化还原是通过Ni-O重杂化发生的,而不是氧化还原.
- 捕获的O2与表面降解和Ni减少有关,而不是散装电荷补偿.
- 在电解质中脱化LiNiO2的不稳定性导致表面降解,并阻碍了Li的运输.
结论:
- 分子氧是表面降解的标志物,而不是LiNiO2.2中的散装氧化还原物.
- 表面不稳定性和Ni的减少是LiNiO2降解的关键.
- 表面稳定策略对于提高LiNiO2电池性能至关重要.
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