Structure stability,electronic property and voltage profile of LiFe1-nNnP1-mMmO4 olivine cathode material

• 作者: Zhi-Hong Cui Xue-Feng Lu Jian-Hua Luo Xin Guo Hong-Tao Xue Fu-Ling Tang
• 来源期刊: 稀有金属（英文版）
• 年，卷（期）: 2021,（12）
• 所属期刊栏目: ORIGINAL ARTICLES
• 页码范围: 3512-3519
• 页数: 8页
• 语种: 英文

摘要

First-principles computational studies under density functional theory (DFT) framework were used to investigate the structural stability,conductivity and voltage profile of LiFe1-nNnP1-mMmO4 (N,M =Si or S) electrode materials.It is found that the LiFeP7/8Si1/8O4 system has the most stable structure.After doping,the band gap values of the systems decrease gradually,and LiFe7/8S1/8PO4 system has a minimum band gap of 1.553 eV,attributed to the hybridization of the Fe-d and S-p orbital electrons.The LiFeP7/8S1/8O4 system demonstrates the characteristic of n-type semiconductor,and other doping systems have the feature of p-type semiconductor.Charge density difference maps show that the covalent property of Si-O bond is enhanced in the LiFeP7/8Si1/8O4 system.The average dis-tance of Li and O atoms in the S doping systems increases from 0.21026 to 0.21486 and 0.21129 nm,respectively,indicating that doping broadens significantly the channel of Li ion de-intercalation in LiFe7/8S1/8PO4 and LiFeP7/8S1/8 O4.Additionally,the results of lithium intercalation potential imply that the voltages of the doping systems fall into the range of 2.23-2.86 V.