Hoang Khang, Oh Myungkeun, Choi Yongki
Center for Computationally Assisted Science and Technology, North Dakota State University, Fargo, North Dakota 58108, United States.
Department of Physics, North Dakota State University, Fargo, North Dakota 58108, United States.
ACS Appl Electron Mater. 2019 Jan 22;1(1):75-81. doi: 10.1021/acsaelm.8b00025. Epub 2018 Dec 28.
Lithium-rich complex transition-metal oxides LiMoO, LiRuO, LiRuO, LiNbO, LiFeO, LiMnO and their derivatives are of interest for high-capacity battery electrodes. Here, we report a first-principles density-functional theory study of the atomic and electronic structure of these materials using the Heyd-Scuseria-Ernzerhof (HSE) screened hybrid functional which treats all orbitals in the materials on equal footing. Dimerization of the transition-metal ions is found to occur in layered LiMoO, in both fully lithiated and partially delithiated compounds. The Ru-Ru dimerization does not occur in fully lithiated LiRuO, in contrast to what is commonly believed; Ru-Ru dimers are, however, found to occur in the presence of neutral lithium vacancies caused by lithium loss during synthesis and/or lithium removal during use. We also analyze the electronic structure of the complex oxides and discuss the delithiation mechanism in these battery electrode materials.
富锂复合过渡金属氧化物LiMoO、LiRuO、LiRuO、LiNbO、LiFeO、LiMnO及其衍生物对于高容量电池电极具有吸引力。在此，我们报道了使用Heyd-Scuseria-Ernzerhof（HSE）筛选混合泛函对这些材料的原子和电子结构进行的第一性原理密度泛函理论研究，该泛函对材料中的所有轨道同等对待。发现在层状LiMoO中，无论是完全锂化还是部分脱锂的化合物，过渡金属离子都会发生二聚化。与通常认为的情况相反，在完全锂化的LiRuO中不会发生Ru-Ru二聚化；然而，发现在合成过程中锂损失和/或使用过程中锂去除导致的中性锂空位存在时会出现Ru-Ru二聚体。我们还分析了复合氧化物的电子结构，并讨论了这些电池电极材料中的脱锂机制。
