High-Rate Charging Induced Intermediate Phases and Structural Changes of Layer-Structured Cathode for Lithium-Ion Batteries
High-Rate Charging Induced Intermediate Phases and Structural Changes of Layer-Structured Cathode for Lithium-Ion Batteries
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高倍率充电引起的中间相和锂离子电池层状正极的结构变化
DOI：
10.1002/aenm.201600597
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发表时间：
2016-11-01
影响因子：
27.8
通讯作者：
Yang, Xiao-Qing
中科院分区：
文献类型：
--
作者：
Zhou, Yong-Ning;Yue, Ji-Li;Yang, Xiao-Qing
利用快速时间分辨原位X射线衍射仪研究了锂离子电池正极材料LiNi1/3Mn1/3Co1/3O2的充电率相关相变过程。在第一次充电过程中，中间相以10C、30C和60C的高速率出现，而不是以0.1C和1C的低速率出现。在充电电流关闭后的松弛过程中，可以连续观察到这些中间相。样品经高速半程充电后，扫描电子显微镜观察到富锂相和贫锂相共存，贫锂相中锂原子以四面体形式占据。高速率感应过电位被认为是形成这一中间贫锂相的驱动力。原位快速X射线吸收结果表明，随着充电速度的增加，镍的氧化速度加快，在30C充电结束时可达到Ni4+状态。这些结果为理解高速充电过程中的层状阴极提供了新的见解。
Using fast time-resolved in situ X-ray diffraction, charge-rate dependent phase transition processes of layer structured cathode material LiNi1/3Mn1/3Co1/3O2 for lithium-ion batteries are studied. During first charge, intermediate phases emerge at high rates of 10C, 30C, and 60C, but not at low rates of 0.1C and 1C. These intermediate phases can be continuously observed during relaxation after the charging current is switched off. After half-way charging at high rate, sample studied by scanning transmission electron microscopy shows Li-rich and Li-poor phases' coexistence with tetrahedral occupation of Li in Li-poor phase. The high rate induced overpotential is thought to be the driving force for the formation of this intermediate Li-poor phase. The in situ quick X-ray absorption results show that the oxidation of Ni accelerates with increasing charging rate and the Ni4+ state can be reached at the end of charge with 30C rate. These results give new insights in the understanding of the layered cathodes during high-rate charging.