材料科学
中子衍射
锂(药物)
氧气
晶格常数
氧化物
阴极
分析化学(期刊)
过渡金属
衍射
晶体结构
结晶学
化学
物理化学
物理
冶金
催化作用
内分泌学
有机化学
生物化学
医学
色谱法
光学
作者
Haodong Liu,Yan Chen,Sunny Hy,Ke An,S. Venkatachalam,Danna Qian,Minghao Zhang,Ying Shirley Meng
标识
DOI:10.1002/aenm.201502143
摘要
Neutron diffraction under operando battery cycling is used to study the lithium and oxygen dynamics of high Li‐rich Li(Li x /3 Ni (3/8‐3 x /8) Co (1/4‐ x /4) Mn (3/8+7 x /24) O 2 ( x = 0.6, HLR) and low Li‐rich Li(Li x /3 Ni (1/3‐ x /3) Co (1/3‐ x /3) Mn (1/3+ x /3) O 2 ( x = 0.24, LLR) compounds that exhibit different degrees of oxygen activation at high voltage. The measured lattice parameter changes and oxygen position show largely contrasting changes for the two cathodes where the LLR exhibits larger movement of oxygen and lattice contractions in comparison to the HLR that maintains relatively constant lattice parameters and oxygen position during the high voltage plateau until the end of charge. Density functional theory calculations show the presence of oxygen vacancy during the high voltage plateau; changes in the lattice parameters and oxygen position are consistent with experimental observations. Lithium migration kinetics for the Li‐rich material is observed under operando conditions for the first time to reveal the rate of lithium extraction from the lithium layer, and transition metal layer is related to the different charge and discharge characteristics. At the beginning of charging, the lithium extraction predominately occurs within the lithium layer. Once the high voltage plateau is reached, the lithium extraction from the lithium layer slows down and extraction from the transition metal layer evolves at a faster rate.
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