Pinning Effect Enhanced Structural Stability toward a Zero-Strain Layered Cathode for Sodium-Ion Batteries
Pinning Effect Enhanced Structural Stability toward a Zero-Strain Layered Cathode for Sodium-Ion Batteries
复制标题
钉扎效应增强了钠离子电池零应变层状阴极的结构稳定性
DOI：
10.1002/anie.202100917
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发表时间：
2021-05-10
影响因子：
16.6
通讯作者：
Zhou, Haoshen
中科院分区：
文献类型：
--
作者：
Chu, Shiyong;Zhang, Chunchen;Zhou, Haoshen
层状氧化物作为钠离子电池的正极材料，因其高容量和组成灵活而受到广泛关注。然而，层状阴极在钠化（脱钠）期间倾向于在电化学和电化学上不稳定。在此，我们提出了在钠存储层状阴极中的钉扎效应和可控钉扎点，以增强结构稳定性并实现最佳电化学性能。在Na_（0.67）Mn_（0.5）Co_（0.5-x）Fe_xO_2中，作为钉扎点的Na位分别占0%、2.5%和7.3%。2.5%的Na位被Fe 3+钉扎有利于抑制潜在的板片滑移，增强结构稳定性，导致0.6%的超低体积变化，并保持了Na离子迁移的平滑二维通道。具有最佳Fe 3+钉扎的Na0.67Mn0.5Co0.4Fe0.1O2阴极可提供超过1000次循环的出色循环性能和高达10 C的优异上级倍率性能。
Layered oxides as the cathode materials of sodium-ion batteries are receiving extensive attention due to their high capacity and flexible composition. However, the layered cathode tends to be thermodynamically and electrochemically unstable during (de)sodiation. Herein, we propose the pinning effect and controllable pinning point in sodium storage layered cathodes to enhance the structural stability and achieve optimal electrochemical performance. 0 %, 2.5 % and 7.3 % transition-metal occupancies in Na-site as pinning points are obtained in Na0.67Mn0.5Co0.5-xFexO2. 2.5 % Na-site pinned by Fe3+ is beneficial to restrain the potential slab sliding and enhance the structural stability, resulting in an ultra-low volume variation of 0.6 % and maintaining the smooth two-dimensional channel for Na-ion transfer. The Na0.67Mn0.5Co0.4Fe0.1O2 cathode with the optimal Fe3+ pinning delivers outstanding cycle performance of over 1000 cycles and superior rate capability up to 10 C.