阴极
材料科学
氧化还原
X射线光电子能谱
杂原子
氧化物
析氧
密度泛函理论
结晶学
化学工程
电极
电化学
化学
物理化学
计算化学
戒指(化学)
有机化学
工程类
冶金
作者
Liuyun Zhang,Chaohong Guan,Yangyang Xie,Huangxu Li,Aonan Wang,Shilei Chang,Jinyun Zheng,Yanqing Lai,Zhian Zhang
标识
DOI:10.1021/acsami.1c24336
摘要
As an attractive cathode candidate for sodium-ion batteries, P2-type Na2/3Ni1/3Mn2/3O2 is famous for its high stability in humid air, attractive capacity, and high operating voltage. However, the low Na+ transport kinetics, oxygen-redox reactions, and irreversible structural evolution at high-voltage areas hinder its practical application. Herein, a comprehensive study of a microbar P2-type Ni2/3Ni1/4Mg1/12Mn2/3O2 material with {010} facets is presented, which exhibits high reversibility of structural evolution and anionic redox activity, leading to outstanding rate capability and cyclability. The notable rate performance (53 mA h g-1 at 20 C, 2.0-4.3 V) contributed to the high exposure of {010} facets via controlling the growth orientation of the precursor, which is certified by density functional theory calculation and lattice structural analysis. Mg substitution strengthens the reversibility of anionic oxygen redox and structural evolution in high-voltage areas that was confirmed by the in situ X-ray diffraction and ex situ X-ray photoelectron spectroscopy tests, leading to outstanding cyclic reversibility (68.9% after 1000 cycles at 5 C) and slowing down the voltage fading. This work provides new insights into constructing electrochemically active planes combined with heteroatom substitution to improve the Na+ transport kinetics and structural stability of layered oxide cathodes for sodium storage.
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