Effects of operating temperatures and hydrogen flow rates during desorption on hydrogen sorption of LaNi5-based tanks and integration with PEMFC stack

Dehydrogenations of two hydrogen storage tanks filled with similar to 1.6 kg MWCNT-doped LaNi5 at different setting temperatures (T-set = 25-50 degrees C) and setting hydrogen flow rates (H-2-FRset = 1.0 and 2.0 SLM) are carried out. By increasing T-set to 50 degrees C under high H2-FRset = 2.0 SLM, dehydrogenation rate significantly enhances up to 1.5 time, and the obtained hydrogen release rate of 0.40-0.55 SLM prolongs for 4 h 35 min. The increase of hydrogen release rate favors the utilization with PEMFC stack owning greater rated power. For dehydrogenation under lower H-2-FRset = 1.0 SLM, although initial dehydrogenation rate is hindered due to the restricted H2-FRset, overall performance based on dehydrogenation time, hydrogen capacity, and the obtained hydrogen release rate are preserved. The integrated PEMFC stack (200 W) with LaNi5-based tanks (T-set = 50 degrees C and H-2-FRset = 2.0 SLM) produces total electrical power of 321.2 Wh. This corresponds to the utilized hydrogen capacity of 0.85 wt % H-2 (similar to 75% of reversible capacity of 1.14 wt % H-2). Some limitations of the current and the power withdrawn from PEMFC stack are observed since the obtained hydrogen release rate from LaNi5-based tanks is deficient. The possibility to improve the performance of PEMFC stack coupled with LaNi5-based hydrogen storage tank is proposed.