第一性原理研究 VPOO 作为可充电 Mg 电池的正极材料。

First-principles study of VPOO as a cathode material for rechargeable Mg batteries.

机构信息

School of Materials Science and Engineering, North Minzu University (Beifang University of Nationalities), Yinchuan, China.

出版信息

Phys Chem Chem Phys. 2019 Feb 27;21(9):4947-4952. doi: 10.1039/c9cp00580c.

DOI:10.1039/c9cp00580c

PMID:30758018

Abstract

The electrochemical properties of VPO4O as a cathode for Mg batteries were studied by performing first principles calculations. Mg insertion features a plateau at about 2.8 V up to Mg0.5VPO4O and then another plateau at around 2.2 V up to MgVPO4O, with a theoretical capacity of about 154 mA h g-1 and 144 mA h g-1, respectively. MgVPO4O is found to be dynamically stable with the absence of negative frequencies in the phonon density of states. The insertion of one Mg reduced two VO6 units instead of reducing only one VO6 unit. In addition, MgVPO4O shows an energy barrier of about 0.58 eV for Mg-ion vacancy migration along the [111] direction, which is comparable to that of many other cathode materials. Our results indicated that MgVPO4O has the potential to be a promising candidate as a cathode material for Mg batteries.

摘要

通过第一性原理计算研究了 VPO4O 作为镁电池正极的电化学性能。Mg 的插入在约 2.8 V 处具有一个平台，直到 Mg0.5VPO4O，然后在约 2.2 V 处具有另一个平台，直到 MgVPO4O，理论容量分别约为 154 mA h g-1 和 144 mA h g-1。MgVPO4O 被发现是动力学稳定的，在声子态密度中没有负频率。插入一个 Mg 会还原两个 VO6 单元，而不是只还原一个 VO6 单元。此外，MgVPO4O 沿 [111] 方向的 Mg 离子空位迁移的能垒约为 0.58 eV，与许多其他正极材料相当。我们的结果表明，MgVPO4O 有可能成为镁电池的一种有前途的正极材料候选物。