Reactive flash sintering and electrical transport properties of high-entropy (MgCoNiCuZn)1-xLixO oxides
Reactive flash sintering and electrical transport properties of high-entropy (MgCoNiCuZn)1-xLixO oxides
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DOI：
10.1111/jace.18343
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发表时间：
2022-01-27
影响因子：
3.9
通讯作者：
Wang, Yiguang
中科院分区：
文献类型：
--
作者：
Ma, Baisheng;Zhu, Yan;Wang, Yiguang
本文采用反应闪速烧结（RFS）法制备了高熵（MgCoNiCuZn）（1-）xLixO氧化物（x = 0、0.1、0.15、0.2、0.3），研究了反应闪速烧结工艺对材料微观结构和电性能的影响。锂掺杂材料表现出混合离子-电子输运行为。通过常规固相反应途径合成的材料中掺入Li后，Co2+氧化成Co3+的现象在闪蒸烧结材料中没有出现。相反，通过RFS合成的锂掺杂材料中的电荷不平衡被氧化物价带中的氧空位和空穴所补偿，它们分别是离子传导和电子传导。离子电导率随着锂离子浓度的增加而增加，形成了更多的氧空位。不同电荷缺陷（Li- m（/）和V-O（中心点中心点））之间的相互吸引形成缺陷配合物，导致缺陷迁移率降低，从而导致高浓度锂离子电导率增加不明显。材料电荷补偿机制的变化表明，通过RFS可以改变这类氧化物的微观结构，从而可以操纵其性能。
In this paper, high-entropy (MgCoNiCuZn)(1-)xLixO oxides (x = 0, 0.1, 0.15, 0.2, and 0.3) were synthesized via reactive flash sintering (RFS), and the effect of RFS process on the microstructure and electrical property of the materials were studied. The Li-doped materials exhibited a mixed ionic-electronic transport behavior. The oxidation of Co2+ into Co3+ upon Li incorporation into the materials synthesized via the conventional solid-state reaction route was not evidenced in the flash sintered materials. Instead, the charge unbalance in the Li-doped materials synthesized via RFS was compensated by oxygen vacancies and holes in the valence band of the oxides, which were accounted for the ionic conduction and electronic conduction, respectively. The ionic conductivity increased upon increasing the Li concentration as more oxygen vacancies were formed. The attraction between defects with different charges (Li-M(/) and V-O(center dot center dot)), which formed defect complexes, led to a decrease in the mobility of the defects, thus resulting in a less pronounced increase in the ionic conductivity at high Li concentrations. The change in the charge compensation mechanism of the materials indicates that the microstructure of such kind of oxides could be altered through RFS, and thus the property may be manipulated.