阴极
材料科学
电化学
晶界
化学物理
化学工程
复合材料
电极
微观结构
化学
物理化学
工程类
作者
Hanshuo Liu,Zhong Xie,Wei Qu,Eben Sy Dy,Svetlana Niketic,Shawn Brueckner,Ken Tsay,Eric Fuller,Christina Bock,Nafiseh Zaker,Gianluigi A. Botton
出处
期刊:Small
[Wiley]
日期:2022-04-11
卷期号:18 (19)
被引量:29
标识
DOI:10.1002/smll.202200627
摘要
Layered Ni-rich lithium transition metal oxides are promising cathode materials for high-energy-density lithium-ion batteries. These cathodes, however, suffer from rapid performance decay under high-voltage operation. In this work, the electrochemical properties and structural evolution of the LiNi0.8 Mn0.1 Co0.1 O2 (NMC811) cathode upon high-voltage cycling are investigated. The results show that the NMC811 cathode not only experiences surface evolution with the formation of Li-deficient rock-salt layers, but also suffers from drastic intragranular structural changes inside bulk grains after high-voltage cycling. Direct evidence for the formation of transition-metal/Li disordering domains with uneven Li content and lattice plane distortion at the internal grains of 4.6 V-cycled NMC811 are provided with their atomic ordering and spatial distribution clearly resolved. The complex intragranular structural changes impede Li+ diffusion inside bulk material, resulting in kinetic limitation and capacity loss. The results demonstrate that the high-voltage cycling would induce severe structural degradation at the grain interior of the cathode material beyond surface evolution, which contributes significantly to the rapid performance decay of the NMC811 cathode. The findings provide new insights for developing effective countermeasures to mitigate this degradation pathway.
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