在氧-氧化电极中的第一循环电压歇斯底里的上层结构控制
Robert A House1, Urmimala Maitra1, Miguel A Pérez-Osorio1
1Department of Materials, University of Oxford, Oxford, UK.
Nature
|December 10, 2019
概括
富含的阴极中的电压歇斯底里与它们的上层结构有关. 一个带层结构抑制离子迁移和氧气释放,使电池性能稳定,避免循环过程中的能量损失.
科学领域:
- 材料科学
- 电化学
- 固态化学
背景情况:
- 通过利用氧化物和过渡金属离子氧化还原,丰富的间隔阴极在电池中提供更高的能量密度.
- 第一个电压歇斯底里,即电池初始充放电过程中的能量损失,是一个重大挑战.
- 这种歇斯底里症通常归因于过渡金属离子位移和氧氧还原过程.
研究的目的:
- 调查阴极超结构在确定第一周期电压歇斯底里的作用.
- 为了比较两个不同的超结构的相关间隔阴极:Na0.75[Li0.25Mn0.75]O2和Na0.6[Li0.2Mn0.8]O2.
- 确定减轻氧降氧阴极中的电压歇斯底里症的策略.
主要方法:
- 两种具有不同的上层结构的介质阴极材料的比较分析.
- 电化学循环和特征.
- 探测电子结构变化的X射线吸收光谱.
主要成果:
- 在充电时,Na0.75[Li0.25Mn0.75]O2中的蜂结构会消失,导致分子氧的形成和离子的迁移.
- 这种结构变化导致在放电过程中不可逆转的电压损失 (歇斯底里).
- 在Na0.6[Li0.2Mn0.8]O2中的带层结构抑制了的失调和氧气的形成,显著降低了歇斯底里.
结论:
- 氧化氧化阴极的第一循环电压歇斯底里非常依赖于阴极的上层结构.
- 一个带层结构有效地抑制过渡金属迁移和氧气释放,从而最大限度地减少歇斯底里.
- 设计具有特定超结构的阴极,如带式,是实现稳定高效电池性能的关键.
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