通过旋转状态调制减少Co/O带重叠,以实现4.6V LiCoO2的稳定高容量
Jicheng Zhang1, Deniz Wong2, Qinghua Zhang3
1Center of Materials Science and Optoelectronics Engineering, College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
Journal of the American Chemical Society
|April 25, 2023
概括
设计的高旋转氧化物 (LCO) 可实现氧化还原,抑制有害的氧离子还原 (OAR) 以提高高压电池的性能和稳定性.
科学领域:
- 材料科学
- 电化学
- 固态化学
背景情况:
- 高压氧化物 (LCO) 具有较高的特定容量,但面临氧气释放和容量降解等挑战.
- 这些问题源于高电压下氧离子回氧化 (OAR) 的不利热力学和动力学.
- 现有的LCO阴极具有结构不稳定性和快速的容量衰减,限制了它们的实际应用.
研究的目的:
- 开发一种具有更高稳定性和性能的高压LCO阴极.
- 从根本上解决LCO电池的氧气释放和结构降解问题.
- 在抑制氧离子氧化还原的同时促进氧化还原, 以提高电池寿命.
主要方法:
- 原子工程高旋转氧化物 (LCO).
- 调整氧化还原机制以有利于氧化还原而不是氧离子还原.
- 使用先进的表征技术研究电子结构和相位过渡.
主要成果:
- 工程LCO中的高旋转CO网络抑制了OAR,减少了氧气释放和有害的CO减排.
- 消除了不良的O3 → H1-3相过渡,增强了结构完整性.
- 模块化的LCO具有超高的速率容量 (1°C时为216 mAh,5°C时为195 mAh) 和优异的容量保留率 (90.4% @100周期,86.9% @500周期).
结论:
- 原子工程高旋转LCO可实现共主导的氧化还原机制,克服高压阴极中的OAR的局限性.
- 这种方法显著提高了电化学性能,结构稳定性和循环寿命.
- 这些发现为设计高能量密度电池的先进阴极材料提供了新的策略.
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