通过抑制 Na 基层层氧化物阴极中的 Li 跨层迁移来实现可持续的 Anionic Redox
Yuansheng Shi1, Fushan Geng2, Yang Sun1
1School of Materials, Sun Yat-sen University, Shenzhen, 518107, China.
ACS nano
|February 7, 2024
概括
研究人员通过扰乱分布开发了一种新的层氧化物阴极 (P3-NLFM). 这一策略抑制了阴离子迁移和氧气释放,显著改善了可充电电池的电池循环稳定性和能量密度.
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:
- 层氧化物阴极由于循环过程中不合理的阳离子电子利用而遭受结构性降解和阴离子迁移.
- 对阴离子氧化还原体所涉及的阴离子迁移的有限理解阻碍了高能量密度电极的设计.
- 无法逆转的阴离子迁移和氧气释放导致常规层氧化物循环稳定性差.
研究的目的:
- 提出一个P3-Na0.67Li0.2Fe0.2Mn0.6O2 (P3-NLFM) 阴极,具有无序的Li分布,以提高电化学性能.
- 为了研究Li亚网格障碍和阳离子氧化还原稳定性之间的相关性.
- 为了抑制层氧化阴极中的阴离子迁移和氧气释放.
主要方法:
- 通过重塑带排序的P3-Na0.6Li0.2Mn0.8O2 (P3-NLM) 来合成P3-NLFM.
- 计算分析包括晶体轨道汉密尔顿群体 (COHP) 和初始分子动力学 (AIMD) 模拟.
- 电化学循环性能评估. 电化学循环性能评估.
主要成果:
- 在P3-NLFM中的无序Li子网格分散了O2p轨道,降低了电荷传输间隙,并抑制了相位过渡.
- 在高电压下,在P3-NLFM中观察到增强的Mn-O相互作用和电子稳定性.
- 在200个循环后,P3-NLFM表现出抑制的Li迁移和损失,达到163mAhg-1容量,保持81.9%,超过P3-NLM (42.9%的保留).
结论:
- 在层氧化物阴极中扰乱子晶格是一种有效的策略,可以提高电化学稳定性和循环性能.
- 通过减轻结构降解,P3-NLFM阴极展示了可充电电池中可持续氧氧回氧的有希望的方法.
- 这项工作提供了通过合理的电极设计来控制离子迁移和氧气释放的见解.
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