Ri-Zhu Yin

Structural Analysis and First-Principles Calculation of Lithium Vanadium Oxide for Advanced Li-Ion Batteries

Abstract The structural and theoretical possibility of lithium vanadium oxide as next generation negative material for advanced Li-ion batteries is discussed. The initial and charged Li 1.1 V 0.9 O 2 compounds show R 3 ¯ m and P 3 ¯ m 1 hexagonal structures respectively from XRD analysis. The electronic structure and chemical bonding of the Li 2.1 V 0.9 O 2 and Li 1.1 V 0.9 O 2 are studied by two kinds of first-principles calculations, molecular orbital (MO) calculations by the DV-X α method and the ab initio total-energy and molecular dynamics program VASP (Vienna Ab-initio Simulation Package). Strong V 3d and O 2p orbital mixing is found by both the DV-X α calculation and XANES measurements in Li 1.1 V 0.9 O 2 .

Electronic Structure and Chemical Bonding of Li1.1Nb0.9O2−y as a Negative Electrode Material for Lithium Secondary Batteries

An oxide, Li1.1Nb0.9O2−y is proposed as a novel active material for the negative electrode of lithium secondary batteries. The material was selected by first principles calculation and its real properties as a negative electrode were measured after it was synthesized by solid state reactions. The electronic structure and chemical bonding of the Li1.1V0.9O2−y (R-3m) and Li1.1Nb0.9O2−y (P63/mmc) were studied by two kinds of first-principles calculations: molecular orbital (MO) calculations by the DV-Xα method and the ab initio total-energy and molecular dynamics program VASP (Vienna Ab-initio Simulation Package). Mulliken’s population analysis was thoroughly conducted to examine the net charge as well as the magnitude of covalent bonding. Mulliken’s charge of Li in Li1.1V0.9O2 (R-3m) and Li1.1Nb0.9O2−y (P63/mmc) and the BOP value for Li–O and V–O are different in their structures.