第一性原理计算：锰酸锂掺杂Fe和Co的性质研究

文章基于密度泛函理论的第一性原理计算，研究了LiMn2O4电池材料在掺杂Fe和Co离子时的电子结构和电化学性能。发现FeCo取代Mn3+在热力学上是会更加稳定，提升电化学性能。掺杂Fe后，LiMn2O4电池材料晶格参数减小(约0.3%)；掺杂Co后，LiMn2O4电池材料晶格参数减小(约0.5%)。这两种掺杂方式让与之相邻的Mn3+被氧化成Mn4+，从而降低了Jahn-Teller畸变情况产生可能性。对于掺Fe尖晶石型锰酸锂(Li8Mn15FeO32)，Mn环境中的Li离子会更容易被提取，第一次放电电压从原来的3.7V增加至4.623V；对于掺Co尖晶石型锰酸锂(Li8Mn15CoO32)，第一次放电电压从原来的3.7V增加至4.101V。研究为锂电池电容量研究提供理论数据的参考。

First-principles calculations: Properties of lithium manganate doped with transition metals Fe and Co

Based on first-principles calculations of density functional theory, the electronic structure and electrochemical properties of LiMn2O4 battery materials doped with Fe and Co ions were investigated. It is found that FeCo instead of Mn3+ is more stable in thermodynamics and improves electrochemical performance. When LiMn2O4 doped with Fe and Co, the lattice parameters will decrease about 0.3% and 0.5%, respectively. These two doping modes allow the adjacent Mn3+ to be oxidized to Mn4+, thus reducing the possibility of Jahn-Teller distortion. For Fe-doped spinel lithium manganate (Li8Mn15FeO32), Li ions in Mn environment can be extracted more easily, and the first discharge voltage increases from 3.7V to 4.623V. For Co doped spinel lithium manganate (Li8Mn15CoO32), the first discharge voltage is increased from 3.7V to 4.101V. This study provides theoretical data reference for the study of lithium battery capacity and solves the problem of low discharge voltage existing in LiMn2O4 battery materials.