LiVPO4F电子结构及锂离子扩散特性的理论研究  

Theoretical Study on Electronic Structure and Li-ion Diffusion Property for LiVPO_4F

作　　者：周传仓[1] 张飞鹏[2,3] 吴红玉[1] 张久兴[3,4] 

机构地区：[1]丽水学院工学院,丽水323000 [2]河南城建学院数理学院,建筑光伏一体化河南省工程实验室,平顶山467036 [3]合肥工业大学材料科学与工程学院,先进功能材料与器件安徽省重点实验室,合肥230009 [4]北京工业大学材料科学与工程学院,新型功能材料教育部重点实验室,北京100124

出　　处：《人工晶体学报》2017年第8期1587-1592,1603,共7页Journal of Synthetic Crystals

基　　金：国家自然科学基金(51572066);河南省自然科学基金(162300410007)

摘　　要：基于密度泛函理论第一性原理计算的方法研究了锂离子电池正极材料LiVPO_4F的晶体结构、电子结构、磁性、插入电压与扩散特性。结果表明,P-O共价键的稳定性较强,在脱锂过程中LiVPO_4F的晶体结构始终保持稳定,体积变化率只有3%。费米能级附近的电子状态主要受V-3d轨道电子的影响,脱锂后体系带隙减小。体系脱锂前后都存在着自旋极化现象,脱锂后体系磁性减弱。LiVPO_4F的平均插入电压为4.53 V,这与实验结果 4.30 V比较吻合。Li比其他的原子有十分明显的向外扩散的趋势。The lattice structure,electronic structure,magnetic property,insert voltage and the Li-ion diffusion properties of LiVPO4F cathode material have been investigated by first-principle calculation method based on the density-functional theory. The calculational results show that the lattice structure of LiVPO4F remains stable during the process of desorption of the Lithium. The percentage of volume change is only 3%; this can be attributed to the stability of P-O covalent bond. The bands near Fermi energy level are mostly formed by V-3d orbital electrons and the band gap energy of LiVPO4F is decreased. The spin polarization phenomenon is found for both systems and the magnetic moment decreases after desorption of Lithium. The averaged insert voltage of LiVPO4F is 4. 53V,which is in agreement with the experimental value of 4. 30V. The Li has obviously stronger diffusion capability comparing with others atoms.

关 键 词：锂离子电池正极材料 第一性原理 LIVPO4F 电子结构 扩散特性 

分 类 号：O649[理学—物理化学]