Hierarchically Porous Iron Alloys with High Sintering Resistance During Cyclic Steam Oxidation and Hydrogen Reduction
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Date
2023-12-08Type
- Journal Article
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Abstract
Hydrogen release/storage materials for iron/air batteries are fabricated as Fe-16Mo and Fe-24Ni (at.%) lattices via 3D-extrusion printing of foamed inks containing oxide microparticles, followed by H2 reduction and sintering. A hierarchical open porosity is designed: (i) channels between walls created during printing, (ii) mesopores within walls, created during ink foaming, and (iii) micropores within ligaments between mesopores, created from partial sintering metal particles and gas escape during cycling. When subjected to H2/H2O redox cycling at 800 & DEG;C, the lattices of both compositions gradually undergo sintering. The Fe-16Mo lattice remains fully redox-active after 50 cycles unlike the Fe-24Ni lattice, which loses 90% of its redox capacity after 30 cycles. The increased lifetime of the Fe-16Mo lattice is attributed to the sintering inhibition of Mo, the formation of a mixture of oxide phases in the oxidized state, and the cyclic formation of submicron Fe2Mo by reduction of MoO2 and Fe2Mo3O8. The microstructure of the foamed walls is examined throughout cycling to track changes in morphology and composition. These are correlated to volume and porosity changes in the lattice. A comparison is made to previously-studied Fe-Mo and Fe-Ni freeze-cast lamellar foams, and variations in performance are discussed in the context of the different architectures. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000631826Publication status
publishedExternal links
Journal / series
Advanced Functional MaterialsVolume
Pages / Article No.
Publisher
Wiley-VCHSubject
3D printing; additive manufacturing; energy storage; iron; redox cyclingMore
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ETH Bibliography
yes
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