AB5-based metal hydride embedded in polyethylene and polymethylmethacrylate for hydrogen storage

• Published in: International journal of hydrogen energy 2024-08, Vol.78, p.952-961
• Main Authors: Ugaddan, Elijah, Violi, Davide, Fiume, Valentina, Barale, Jussara, Luetto, Carlo, Rizzi, Paola, Baricco, Marcello
• Format: Article
• Language: English
• Subjects: Hydrogen storage; LaNi5; Metal hydride; Metal hydride reactor; Polymer composite
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2024.06.383

Loose powder in metal hydride reactors poses challenges, such as poor thermal conductivity and tube deformation. To address these issues, the metal powder can be encapsulated in a polymer-based matrix to form pellets. This encapsulation helps make the pellets oxygen-impermeable, capable of accommodating the volumetric expansion of metal hydrides, and increases system processability. This study investigates the use of polymer-based pellets containing AB5-based compounds for ambient hydrogen storage. Polymers were selected using ANSYS Granta software, and polyethylene and polymethylmethacrylate were chosen. The AB5 alloy activation in the pellet occurs efficiently after 3 min at 20 °C and 30 bar of hydrogen, facilitated by ball milling-induced reactive surfaces and increased grain boundaries. The optimized pellet, comprising 90 wt% AB5 powder in a PE matrix, exhibits stable hydrogen storage properties, with good mechanical resistance and minimal powder loss (below 3%) over 20 hydrogen sorption cycles in an in-house fabricated single-tube metal hydride reactor. [Display omitted] •Loose metal hydride powder bound in a polymer matrix formed pellets without solvents, simplifying handling and processing.•PE and PMMA were selected via ANSYS Granta as suitable matrix materials for hydride pellets, ensuring effective binding.•90 wt.% AB5 in a PE matrix demonstrated stable H₂ storage, strong mechanical properties, and less than 3% powder loss.•AB5 alloy in the pellets activated within 3 min at 20°C and 30 bar H₂, enabling rapid and efficient hydrogen storage.•Pellets maintained consistent performance through 20 hydrogen sorption cycles in a custom single-tube reactor.