First Principles Analysis for Electronic Structure of LaNi_5-xCo_x Alloys

Electronic structures of LaNi_5-xCo_x (x = 0, 0.5, 1) hydrogen-storage alloy were studied theoretically using the method of total energy based on the density functional theory (DFT). The plane wave function was selected as the basis set in combination with the ultrasoft pseudopotential technology. Crystal structure, energy band structure, electronic density of states, and Mulliken density of LaNi_5-xCo_x were calculated. The results indicated that valence electrons were mainly fastened around Fermi energy (E_F) and E_F moved toward the direction of lower energy with the increase of the Co content. According to the analysis of Mulliken overlap populations, the numerical values of the bonds between Ni_3g-Ni_3g and Ni_2c-Ni_2c decreased. It showed that Co doping led to the decrease in the bond energy between Ni-Ni. However, the values on the bond between La-Ni increased and the relevant bond energy increased.