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

Abstract: 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 4.53 V, which is in agreement with the experimental value of 4.30 V.The Li has obviously stronger diffusion capability comparing with others atoms.

Key words: 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 4.53 V, which is in agreement with the experimental value of 4.30 V.The Li has obviously stronger diffusion capability comparing with others atoms.