阴极
材料科学
氧化还原
化学物理
氧气
离子
氧化物
格子(音乐)
纳米技术
凝聚态物理
化学
物理化学
物理
冶金
声学
有机化学
作者
Pengfei Yan,Jianming Zheng,Zhen‐Kun Tang,Arun Devaraj,Guoying Chen,Khalil Amine,Ji‐Guang Zhang,Chongmin Wang
标识
DOI:10.1038/s41565-019-0428-8
摘要
Surfaces, interfaces and grain boundaries are classically known to be sinks of defects generated within the bulk lattice. Here, we report an inverse case by which the defects generated at the particle surface are continuously pumped into the bulk lattice. We show that, during operation of a rechargeable battery, oxygen vacancies produced at the surfaces of lithium-rich layered cathode particles migrate towards the inside lattice. This process is associated with a high cutoff voltage at which an anionic redox process is activated. First-principle calculations reveal that triggering of this redox process leads to a sharp decrease of both the formation energy of oxygen vacancies and the migration barrier of oxidized oxide ions, therefore enabling the migration of oxygen vacancies into the bulk lattice of the cathode. This work unveils a coupled redox dynamic that needs to be taken into account when designing high-capacity layered cathode materials for high-voltage lithium-ion batteries.
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