Chu Shiyong, Zhang Chunchen, Xu Hang, Guo Shaohua, Wang Peng, Zhou Haoshen
College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Umezono 1-1-1, Tsukuba, 305-8568, Japan.
Angew Chem Int Ed Engl. 2021 Jun 7;60(24):13366-13371. doi: 10.1002/anie.202100917. Epub 2021 May 10.
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 Na Mn Co Fe O . 2.5 % Na-site pinned by Fe 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 Na Mn Co Fe O cathode with the optimal Fe pinning delivers outstanding cycle performance of over 1000 cycles and superior rate capability up to 10 C.
层状氧化物作为钠离子电池的阴极材料，因其高容量和灵活的组成而受到广泛关注。然而，层状阴极在脱钠/嵌钠过程中往往在热力学和电化学方面不稳定。在此，我们提出了钠离子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NaMnCoFeO中获得了0%、2.5%和7.3%的过渡金属占据Na位作为钉扎点。由Fe钉扎的2.5%Na位有利于抑制潜在的板层滑动并增强结构稳定性，导致超低的0.6%体积变化，并保持钠离子转移的平滑二维通道。具有最佳Fe钉扎的NaMnCoFeO阴极具有超过1000次循环的出色循环性能和高达10C的优异倍率性能。
