Papers by Author: Choong-N. Park

Abstract: Hydrogen absorption-desorption cycling induced by pressure change in a closed system were carried out with LaNi5, La0.7Ce0.3Ni4Cu and TiFe0.9Ni0.1 alloys. PC isotherms measured during the cycling showed some changes in hydrogen storage capacity, plateau pressure and hysteresis of the alloys. . The half capacity life of LaNi5 alloy can be projected as 70,000 cycles for room temperature pressure cycling. When La0.7Ce0.3Ni4Cu alloy was pressure cycled both of the plateau pressures were decreased significantly and continuously. TiFe0.9Ni0.1 alloy showed a good resistance to cyclic degradation. Heat treatments of the degraded alloys under 1 atm of hydrogen gas recovered most of the hydrogen storage properties to the initial level even though they were degraded again more rapidly upon subsequent cycling.