Microstructural evolution during hydrogen sorption cycling of Mg―FeTi nanolayered composites

摘要: Abstract This paper describes the microstructural evolution of Mg–FeTi mutlilayered hydrogen storage materials during extended cycling. A 28 nm Mg–5 nm FeTi multilayer has comparable performance to a cosputtered material with an equivalent composition (Mg–10%Fe–10%Ti), which is included as baseline case. At 200 °C, layers act barrier, preventing agglomeration Mg particles. 300 °C, initial structure preserved up 35 cycles, followed by fracturing in in-plane direction and progressive delamination observed electron microscopy. Concurrently, increase grain size was from 32 76 nm between cycles 300. As result, absorption kinetics deteriorate cycling, although 90% total capacity still absorbed within 2 min after many 300 cycles. The desorption kinetics, on other hand, remain rapid stable, complete 4.6 wt.% H achieved 1.5 min at ambient pressure. In addition showing good performance, multilayers are excellent model system for studying relation microstructure absorption/desorption kinetics.