描述影响单晶高层氧化物阴极电化学行为的因素
Ethan Y Bar-Nur1, Arumugam Manthiram1
1Materials Science and Engineering Program and Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States.
ACS applied materials & interfaces
|October 23, 2025
概括
在高压循环过程中,表面重建驱动高阴极的容量衰减. 优化/比率和使用化电解质添加剂可以提高离子电池的稳定性.
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:
- 高 (Ni) 单晶阴极 (LiNi1-x-yMnxCoyO2,NMCs) 对离子电池 (LIB) 是一个有前途的产品.
- 在高电压下,容量衰减,特别是 H2-H3 后的相位过渡,限制了它们的实际应用.
- 了解降解机制对于提高NMC阴极性能至关重要.
研究的目的:
- 调查 (Co) 和 (Mn) 比例对单晶NMC高压循环稳定性的影响.
- 评估电解质添加剂,特别是单乙烯碳酸盐和LiF2PO2在减轻降解中的作用.
- 阐明表面重建,相位过渡和容量损失之间的关系.
主要方法:
- 合成单晶LiNi0.8MnxCo0.2-xO2 (x = 0.2, 0.1, 0) 阴极的方法.
- 在LiPF6/乙基甲基碳酸盐电解质中进行电化学测试,含有或不含有化添加剂.
- 对降解机制的分析,重点关注表面重建和相位过渡动力学.
主要成果:
- 表面重建被确定为高压容量损失的主要原因.
- 在没有Co-free阴极和没有化电解质组件的情况下,降解更为明显.
- 由H2-H3动力学引起的机械应力与电解质被动不良之间的协同作用加剧了容量衰减.
结论:
- 限制阴极阻抗增长是提高高压循环性能的关键.
- 调整散装剂 (Co/Mn比) 和电解质化学是稳定性的有效策略.
- 表面稳定和优化的界面动力学对于持久的高能LIBs至关重要.
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