Hydrogen Storage Properties of La0.6M0.4Ni4.8Mn0.2 (M=Y, Nd) Alloys forMetal Hydride Air-conditioning system

摘要

Several LaNi5 based CaCu5 hexagonal structured alloys La0.6M0.4Ni4.8Mn0.2 (M=Y, Nd) wereprepared and their hydrogen storage properties were studied in order to develop a suitablematerial for metal hydride air-conditioning system. The metal hydride used in air-conditioningsystem should have a suitable plateau pressure, high hydrogen absorption capacity, lowplateau sloping and hysteresis. La0.6Y0.4Ni4.8Mn0.2 shows good properties for air-conditioningsystem but has poor hysteresis and sloping characteristics. The sloping, hysteresis propertyand hydrogen capacity has been effectively improved by the substitution of Nd for Y, but thehydrogen absorption kinetics decreased. The results show that the addition of Cu is veryeffective in improving the hydrogen absorption kinetics. La0.6Nd0.4Ni4.8Mn0.2Cu0.1 shows goodplateau characteristics with small hysteresis and sloping as well as good kinetics. For eachcompound of La0.6M0.4Ni4.8Mn0.2, a relationship is made between the unit cell parameter c/aand effective hydrogen storage capacity. The effective hydrogen storage capacity increaseswith decrease of the unit cell parameter c/a.