Sintering Inhibition Enables Hierarchical Porosity with Extreme Resistance to Degradation during Redox Cycling of Fe-Mo Foams
Sintering Inhibition Enables Hierarchical Porosity with Extreme Resistance to Degradation during Redox Cycling of Fe-Mo Foams
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DOI：
10.1016/j.actamat.2023.119015
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发表时间：
2023-05
期刊：
影响因子：
9.4
通讯作者：
Jacob B. Mack;Samuel M. Pennell;D. Dunand
中科院分区：
文献类型：
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作者：
Jacob B. Mack;Samuel M. Pennell;D. Dunand
高温（800 ºC）蒸汽-氢氧化还原循环，相关的网格规模的能量存储，研究了铁基冷冻铸造层状泡沫。与以前研究的Fe、Fe-Ni和Fe-Co泡沫材料相比，Fe-25 Mo泡沫材料具有更高的结构抗损伤性。利用原位X射线衍射，显微镜，X射线断层扫描，强烈的烧结抑制观察Fe-Mo泡沫，创建一个分层多孔层状结构。这导致（i）薄片之间的宽通道，使得能够实现高宏观孔隙率（约78%），其可以适应气体流动以及体积膨胀而没有薄片接触，和（ii）薄片内的微孔，提供额外的自由体积以适应氧化期间的膨胀，限制薄片的溶胀和Kirkendall孔的形成。这些综合效应使微观结构在循环过程中几乎完全可逆，防止通过内部层状屈曲、开裂、接触和烧结产生的损坏，在连续50次氧化还原循环后仍具有非常高的孔隙率（65%）。
High-temperature (800 ºC) steam-hydrogen redox cycling, relevant to grid-scale energy storage, is studied for iron-based freeze-cast lamellar foams. In contrast to previously studied Fe, Fe-Ni, and Fe-Co foams that rapidly degrade, Fe-25Mo foams feature a much-enhanced structural damage resistance. Utilizingin-situx-ray diffraction, microscopy, and x-ray tomography, strong sintering inhibition is observed in Fe-Mo foams, creating a hierarchically porous lamellar structure. This leads to (i) wide channels between lamellae, enabling high macroscopic porosity (∼78%) which can accommodate gas flow as well as volumetric expansion without lamellar contact, and (ii) microporosity within lamellae, providing additional free volume to accommodate expansion during oxidation, limiting both swelling of the lamellae and the formation of Kirkendall pores. These combined effects enable a near-complete reversibility of the microstructure during cycling, preventing damage producedviainternal lamellar buckling, cracking, contacting and sintering, with a remarkably high porosity (65%) remaining after 50 consecutive redox cycles.