Ding Feixiang, Zhao Chenglong, Xiao Dongdong, Rong Xiaohui, Wang Haibo, Li Yuqi, Yang Yang, Lu Yaxiang, Hu Yong-Sheng
Key Laboratory for Renewable Energy, Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
Huairou Division, Institute of Physics, Chinese Academy of Sciences, Beijing 101400, China.
J Am Chem Soc. 2022 May 11;144(18):8286-8295. doi: 10.1021/jacs.2c02353. Epub 2022 Apr 26.
Na-ion layered oxide cathodes (NaTMO, TM = transition metal ion(s)), as an analogue of lithium layered oxide cathodes (such as LiCoO, LiNiCoMnO), have received growing attention with the development of Na-ion batteries. However, due to the larger Na radius and stronger Na-Na electrostatic repulsion in NaO slabs, some undesired phase transitions are observed in NaTMO. Herein, we report a high-entropy configuration strategy for NaTMO cathode materials, in which multicomponent TMO slabs with enlarged interlayer spacing help strengthen the whole skeleton structure of layered oxides through mitigating Jahn-Teller distortion, Na/vacancy ordering, and lattice parameter changes. The strengthened skeleton structure with a modulated particle morphology dramatically improves the Na transport kinetics and suppresses intragranular fatigue cracks and TM dissolution, thus leading to highly improved performances. Furthermore, the elaborate high-entropy TMO slabs enhance the TM-O bonding energy to restrain oxygen release and thermal runaway, benefiting for the improvement of thermal safety.
钠离子层状氧化物阴极（NaTMO，TM = 过渡金属离子）作为锂层状氧化物阴极（如LiCoO、LiNiCoMnO）的类似物，随着钠离子电池的发展受到了越来越多的关注。然而，由于NaO板中Na半径较大且Na-Na静电排斥较强，在NaTMO中观察到一些不期望的相变。在此，我们报道了一种用于NaTMO阴极材料的高熵构型策略，其中具有扩大层间距的多组分TMO板通过减轻 Jahn-Teller 畸变、Na/空位有序化和晶格参数变化来帮助强化层状氧化物的整体骨架结构。具有调制颗粒形态的强化骨架结构显著改善了Na传输动力学并抑制了晶内疲劳裂纹和TM溶解，从而导致性能大幅提高。此外，精心设计的高熵TMO板增强了TM-O键能以抑制氧释放和热失控，有利于热安全性的提高。
