Computational analysis of composition-structure-property-relationships in NZP-type materials for Li-ion batteries
Computational analysis of composition-structure-property-relationships in NZP-type materials for Li-ion batteries
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DOI：
10.1063/1.5091969
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发表时间：
2019-01
影响因子：
3.2
通讯作者：
D. Mutter;D. Urban;C. Elsässer
中科院分区：
文献类型：
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作者：
D. Mutter;D. Urban;C. Elsässer
具有NaZr_2 $（PO_4 $）$_3$（NZP）结构的化合物被认为是锂离子电池固态电解质的理想材料。利用密度泛函理论（DFT），对18种NZP化合物LiX 2（LO 4）3（X = Ti，V，Fe，Zr，Nb，Ru，Hf，Ta，Os，L = P，Mn）的空位迁移活化能进行了系统的计算筛选.它示出了如何不同的离子半径的阳离子取代的影响结构特征，如八面体体积周围的锂离子的初始和过渡态网站上，这会影响活化能（“组成-结构-性能”的关系）。普遍的假设，形成三角形排列的氧原子在一定的位置沿着迁移路径的结构瓶颈决定的能量障碍锂迁移是不支持的DFT结果。相反，迁移离子在初始和过渡态的离子邻域需要考虑到相关的结构的活化能。这一结论也适用于含Na的NZP化合物。
Compounds crystallizing in the structure of NaZr$_2$(PO$_4$)$_3$ (NZP) are considered as promising materials for solid state electrolytes in Li-ion batteries. Using density functional theory (DFT), a systematic computational screening of 18 NZP compounds, namely LiX$_2$(LO$_4$)$_3$ with X = Ti, V, Fe, Zr, Nb, Ru, Hf, Ta, Os, and L = P, Mn is performed with respect to their activation energies for vacancy-mediated Li migration. It is shown how the different ionic radii of the cationic substitutions influence structural characteristics such as the octahedron volumes around Li ions on the initial and transition state sites, which affect the activation energies (''composition-structure-property'' relationships). The prevalent assumption that structural bottlenecks formed by triangularly arranged oxygen atoms at a certain location along the migration path determine the energy barriers for Li migration is not supported by the DFT results. Instead, the ionic neighborhood of the migrating ion in the initial and in the transition state needs to be taken into account to relate the structure to the activation energies. This conclusion applies to Na containing NZP compounds as well.