LiFePO4锂离子脱嵌过程第一性原理研究

PDF全文下载：  201904006.pdf

文章编号： 16726987（2019）04005406； DOI： 10.16351/j.16726987.2019.04.006

贾军， 高洪涛*(青岛科技大学 化学与分子工程，山东 青岛 266042)

摘要： 采用第一性原理方法对LiFePO4及微量Cr掺杂LiFePO4的电子结构和性质进行了理论研究。结果发现：随着Li原子的脱出，形成空位后的Fe—O键变长，扩宽了Li原子传输通道，有利于Li原子在通道中的迁移。不同点缺陷浓度LiFePO4的态密度分析表明，充放电过程中电子结构发生了微小的变化，但晶体仍然保持了绝缘体性质。当完全脱锂后，费米能级附近的能级态主要是由Fe和微弱的O组成。掺杂微量的Cr后，费米能级处电子态增多，导电性能增强，LiFePO4的电化学性能得到改善。

关键词： LiFePO4； 第一性原理； 电子结构； 电化学性能

中图分类号： O 063文献标志码： A

引用格式： 贾军， 高洪涛. LiFePO4锂离子脱嵌过程第一性原理研究\[J\]. 青岛科技大学学报（自然科学版）， 2019， 40（4）： 5459.

JIA Jun， GAO Hongtao. First principle study of LiFePO4 lithium ion deintercalation process\[J\]. Journal of Qingdao University of Science and Technology（Natural Science Edition), 2019, 40(4)： 5459.

First Principle Study of LiFePO4 Lithium Ion Deintercalation Process

JIA Jun， GAO Hongtao

(College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology，Qingdao 266042, China)

Abstract: In this work, firstprinciple calculations based on density functional theory were implemented to investigate the electronic structure and properties of LiFePO4 and trace Crdoped LiFePO4. It was found that with Li atoms releasing, the Fe—O bond became longer, which widened the transport channel of Li atom was widened and facilitated the migration of Li atoms. The calculated state of density illustrated that showed that the electronic structure changed slightly during the charge and discharge process, but the crystal still retained the insulator properties. The energy level near the Fermi level was mainly composed of Fe3d and O2p after complete delithiation. After doping with a small amount of Cr, there appeared impurity state near the fermi level, which was greatly conducive to the excitation of electrons into the conduction band, thereby achieving enhanced electron transport capacity and its electrochemical performance.

Key words: LiFePO4； firstprinciple calculations； electronic properties； electrochemical performance

收稿日期：  20180813

基金项目： 国家自然科学基金项目(41573103)；山东省重点研发计划项目(2017GSF16105).

作者简介： 贾军（1991—），硕士研究生.*通信联系人.