操纵局部化学和连贯结构,以实现高速率和长寿命的离子电池阴极
Haoji Wang1, Hongyi Chen1, Yu Mei1
1College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
ACS nano
|May 10, 2024
概括
这项研究揭示了分层的过渡金属氧化物中的故障机制,并介绍了一种提高结构完整性和离子传输以提高电池性能的策略.
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
- 固态化学 固态化学
背景情况:
- 在高压阴极中使用的多层过渡金属 (TM) 氧化物面临容量衰减和低速性能,特别是在高电荷状态 (SoC) 时.
- 失效机制包括Jahn-Teller扭曲,层间排斥和氧气不稳定,导致结构损坏.
- 改善结构完整性和离子传输对于先进的离子电池至关重要.
研究的目的:
- 揭示高压分层氧化物阴极的故障机制.
- 制定改善结构完整性和离子 (Na+) 运输动力学的战略.
- 为离子电池开发高性能阴极材料.
主要方法:
- 密度函数理论 (DFT) 计算以阐明故障机制和设计策略.
- 射线吸收光谱 (XAS) 和现场表征技术用于分析结构变化.
- 用Zn2+诱导器修改的P2/O3双相阴极的合成和电化学测试.
主要成果:
- 鉴定出高雅恩-泰勒[Mn3+O6]度和氧气不稳定性是关键的故障因素.
- 证明电子结构调制和连贯的相互交织结构增强了结构完整性和Na+扩散.
- 实现了卓越的电化学性能:92.6%的初始库伦比克效率,86.5mAh的g-1在10C,和71.6%的容量保留在5C300个循环后.
结论:
- 电荷定位和连贯结构的二合一策略有效地减轻了多层氧化物的故障机制.
- 优化的Na+运输和结构稳定性导致大幅提高速度能力和循环寿命.
- 这项工作为设计下一代用于离子电池的高压阴极材料提供了基本的见解.
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