Restoration of long range order of Na ions in NaxCoO2 at high temperatures by sodium site doping
Restoration of long range order of Na ions in NaxCoO2 at high temperatures by sodium site doping
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通过钠位点掺杂在高温下恢复 NaxCoO2 中钠离子的长程有序
DOI：
10.1016/j.commatsci.2015.07.043
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发表时间：
2015
影响因子：
3.3
通讯作者：
H Katayama-Yoshida
中科院分区：
文献类型：
--
作者：
M H N Assadi;H Katayama-Yoshida
我们用密度泛函理论系统地研究了掺入Cu、Y、Sn、W、Au和Bix=0.50、0.75和1.00的NaxCoO2体系。无论钠的浓度如何，锡、钨、铋总是取代钴，而金总是取代钠。然而，对于Cu和Y，取代位取决于Na的浓度。与已有的实验数据相比，我们发现当掺杂取代Na位时，热电性能得到了提高。在这种情况下，令人惊讶的是，尽管载流子复合导致空穴浓度降低，但电阻率仍然下降。我们认为载流子迁移率的提高是观察到的电阻率降低的原因。
We have systematically investigated the NaxCoO2system doped with Cu, Y, Sn, W, Au and Bi forx= 0.5, 0.75 and 1.00 using density functional theory. Sn, W and Bi always substitute a Co while Au always substitute a Na regardless of Na concentration. However, for, Cu and Y, the substitution site depends on Na concentration. When compared to the available experimental data, we find that thermoelectric performance is enhanced when the dopants substitute a Na site. In this case, surprisingly, resistivity decreases despite the reduced hole concentration caused by carrier recombination. We propose improved carrier mobility to be the cause of observed reduced resistivity.