Processing of Advanced Foam Scaffolds for Iron-Air Battery Applications

用于铁-空气电池应用的先进泡沫支架的加工

• 批准号: 1562941
• 负责人: David Dunand
• 金额: $ 32.06万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1562941&HistoricalAwards=false
• 关键词: Processing; Advanced; Foam; Scaffolds; Iron

The generation, storage, and local use of hydrogen to generate electric power via fuel cells are critical to reaching an electrical grid with low-to-zero carbon dioxide emissions, benefiting the U.S. economy and worldwide society. In recent years, iron oxide powder has attracted attention as an inexpensive, non-toxic option to store and create pure hydrogen through the iron-oxide reduction/oxidation ("redox") reaction. One of the main problems associated with this cyclical redox reaction is powder pulverization and subsequent agglomeration and consolidation. These effects drastically reduce the high surface areas needed for the reaction. Thus, maintaining stability, high surface area and high gas permeability in the powder bed after multiple redox cycles are the main challenges for this promising technology. This award supports research to develop a structure that takes advantage of novel processing approaches to create iron scaffolds which can maintain structural integrity, high permeability and high surface area during the redox cycles, thus enabling a novel, inexpensive and non-toxic iron-air battery for large scale use.In this research program, the investigators will directionally freeze an aqueous suspension of iron oxide nanopowders to create ice dendrites, which will push the particles into interdendritic space, thus creating a network of iron oxide powders walls. After hydrogen reduction, this network is sintered into a continuous scaffold with directionally aligned channels templating the original ice dendrites, surrounded by iron walls with high surface area and enough internal free space to achieve the microstructural stability needed to withstand multiple reduction/oxidation cycles without sintering or pulverization. The scaffold stability will be further improved by adding various materials to the iron oxide nanopowder suspension: (i) nickel oxide powders which are co-reduced to form iron-nickel solid solution walls with higher strength; (ii) space-holder powders such as strontium fluoride, which can be evaporated from the scaffold walls to generate further porosity within the walls and increase their surface area and the free volume to accommodate volume changes and (iii) inert reinforcements such as ceramic particles, which will strengthen and stiffen the scaffold walls. Mechanical testing will be used to examine relative structural degradation of samples after reduction/oxidation cycles, and x-ray tomography and finite element modeling will be used to map and examine 3-dimensional scaffold structure and stress distribution within its walls during the volumetric changes associated with the redox cycles.

通过燃料电池产生电力的一代，存储和本地用途对于达到具有低到零二氧化碳排放的电网至关重要，从而使美国经济和全球社会受益。近年来，氧化铁粉末引起了人们的注意，是一种廉价的无毒选择，可以通过氧化铁还原/氧化（“氧化还原”）反应来存储和产生纯氢。与这种周期性氧化还原反应相关的主要问题之一是粉末粉碎以及随后的聚集和巩固。这些影响大大减少了反应所需的高表面积。 因此，在多个氧化还原周期后保持稳定性，高表面积和粉末床的高气体渗透性是这项有前途的技术的主要挑战。 This award supports research to develop a structure that takes advantage of novel processing approaches to create iron scaffolds which can maintain structural integrity, high permeability and high surface area during the redox cycles, thus enabling a novel, inexpensive and non-toxic iron-air battery for large scale use.In this research program, the investigators will directionally freeze an aqueous suspension of iron oxide nanopowders to create ice dendrites, which will push the particles into基础间空间，从而形成了一个氧化铁网络。还原氢后，该网络被烧结成连续的支架，该连续支架具有指向对齐的通道，这些通道模板是原始的冰树突，周围是具有高表面积和足够内部自由空间的铁壁包围，以实现在不烧伤或粉碎的情况下承受多重还原/氧化循环所需的微观结构稳定性。通过向氧化铁纳米伏悬浮液中添加各种材料，将进一步提高脚手架稳定性：（i）氧化镍粉被共同减少以形成具有较高强度的铁核固体溶液壁； （ii）可以从脚手架壁中蒸发的太空持有粉，例如氟化腹膜，以在墙壁内产生进一步的孔隙度，增加其表面积和自由体积以适应体积变化，并且（iii）惰性增强剂，例如陶瓷颗粒，可以增强和僵硬的cap虫壁。机械测试将用于检查还原/氧化周期后样品的相对结构降解，X射线断层扫描和有限元建模将用于在与Redox循环相关的体积变化期间绘制和检查其壁中的3维支架结构和应力分布。