Absorption and Desorption Rates of H2 and D2 for LaNi5, LaCo5, LaNi2Co3, and FeTi.
Abstract
Rates of H2 absorption and desorption were measured for LaNi5, LaCo5, LaNi2Co3, and FeTi in order to examine the limitations of these alloys for storing H2 in high-power Ni-H2 satellite batteries. If the H2 absorption and desorption rates are sufficient, H2 storage in the alloys could increase the energy density and decrease the volume of Ni-H2 spacecraft batteries. The rate measurements showed that the quantity of H2 absorbed or desorbed was linearly dependent on the square root of time for all four alloys. This rate law indicated that the rate-controlling step was hydrogen atom diffusion through an adherent hydride layer to the alloy surface. The activation energy for desorption from LaNi5 was 4.5 plus or minus 0.5 kcal. Even at 0.4 C, the H2 absorption and desorption rates were sufficient that batteries could be charged and dishcarged in less than 30 min. Rates for D2 were also determined and found to be lower than for H2. The use of LaCo5 and LaNi2Co5 permitted even lower pressures than those needed with LaNi5 for H2 storage in Ni-H2 satellite batteries. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 19, 1977
- Accession Number
- ADA039518
Entities
People
- Christopher P. Meilleur
- Michael R. Martinelli
- Stanley W. Mayer
Organizations
- The Aerospace Corporation