Stability of LaNi5-xSnx cycled in hydrogen

摘要

In this work we study the effect of cycling in hydrogen with a purity grade 4.5 of six alloys belonging to the LaNi5-xSnx family for 0 <= x <= 0.5. Measurements consist in the alternate repetition of absorption reactions at a temperature of 316 K and an initial pressure of 800 kPa, each followed by a desorption reaction at the same temperature and a maximum backpressure of 2 kPa. All samples present good stability, preserving at least 98 of their initial capacity after 100 cycles. Samples with composition LaNi5 and LaNi4.55Sn0.45 were subjected to 1000 cycles, after which we observe a higher stability from the Sn-containing alloy (96 of the initial capacity preserved versus 92 for LaNi5). Absorption characteristic times do not suffer important changes in either case. Desorption is gradually retarded when Sn content is higher than 0.4 at. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.