First-principles electronic structure calculations were performed in order to investigate the effect of hydrogen upon the stability of the Ni vacancy following hydrogen desorption. The calculated binding energy of hydrogen to the Ni vacancy indicated that up to two H atoms were trapped at the Ni vacancy. The formation energy of the Ni vacancy which trapped H atoms was found to decrease with the number of H atoms and to become negative when two H atoms were trapped. The results suggested that the Ni vacancy was energetically stabilized by trapping two H atoms during the hydrogen desorption process.

Effect of Hydrogen on Stability of Vacancy in LaNi5. M.Mizuno, H.Araki, Y.Shirai: Journal of Physics - Conference Series, 2009, 165[1], 012043 (6pp)