摘要
针对分别掺杂Ni、Co、Al的尖晶石LiMn_(2)O_(4),采用基于密度泛函理论的第一性原理计算方法,分析反铁磁层和铁磁层沿[001]方向交替排列的磁性构型的合理性。结果表明,此磁结构下表现出Mn^(3+)/Mn^(4+)沿[001]方向交替排列的价态分布。Ni、Co、Al三种掺杂原子都倾向于替换Mn^(3+)层上的Mn,占据16d位后价态表现为Ni^(2+)、Co^(3+)和Al^(3+)。Al与Ni掺杂均能抑制掺杂点位的Jahn-Teller畸变,且Ni掺杂后其最近邻的Mn^(3+)被氧化为Mn^(3+),使结构更稳定,而Co掺杂可能导致更严重的Jahn-Teller畸变。Al^(3+)和Co^(3+)可显著降低Li离子的两条路径扩散能垒,Ni^(2+)在Mn^(3+)的协同作用下可进一步降低低能垒路径的能垒。
For spinel LiMn_(2)O_(4)doped with Ni, Co and Al, the first-principles calculations method based on density functional theory is used to analyze the magnetic configuration of the anti ferromagnetic layer and the ferromagnetic layer alternately arranged along the [001] direction rationality. The result show that this magnetic structure shows the valence distribution of Mn^(3+)/Mn^(4+)alternately arranged along the [001] direction. The doping calculation shows that all three kinds of atoms tend to replace Mn in the Mn^(3+)layer, and the valence states of doped atoms are Ni^(2+), Co^(3+)and Al^(3+)after occupying the 16 d site. Al and Ni doping can inhibit the Jahn-Teller distortion of doping sites, and its nearest neighbor Mn^(3+)is oxidized to Mn^(3+)after Ni doping, which is more conducive to the stability of the structure. Co doping may result in more severe Jahn-Teller aberrations. The Al^(3+)and Co^(3+)can significantly reduce the diffusion energy barrier of Li ion in two paths, and Ni^(2+)further reduce the low energy barrier path’s energy barrier under the synergistic action of Mn^(3+).
作者
李旭
王建川
杜勇
LI Xu;WANG Jianchuan;DU Yong(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China)
出处
《粉末冶金材料科学与工程》
2021年第5期387-395,共9页
Materials Science and Engineering of Powder Metallurgy
基金
中德合作研究小组项目(GZ1528)。
