First Principles Design of Ionomers for Facile Ion Transport

方便离子传输的离聚物的第一原理设计

• 批准号: 0933391
• 负责人: Ralph Colby
• 金额: $ 30.35万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0933391&HistoricalAwards=false
• 关键词: First; Principles; Design; Ionomers; Facile

0933391ColbyCurrent lithium batteries use a nanoporous polypropylene membrane filled with lithium salts dissolved in high dielectric constant solvents as the separator between electrodes. This technology has problems with safety and regardless of the choice of anion, which moves 5-10X faster than Li+, resulting in anion build-up at electrodes that significantly reduces battery efficiency, maximum battery power and recharge time. The obvious choice for a replacement membrane is a single-ion conducting polymer (ionomer) that has all anions covalently bonded to the polymer, has no solvent to leak out of the battery and can easily be made into a thin film. Unfortunately, the best ionomer membranes have Li+ ion conductivities 100X too small for practical applications. The PI leads a five-PI DOE-funded team that is attempting to design superior ionomers for lithium battery membranes, but also is facing a very broad design space, with 30 polar groups that could be added as side chains and 20 anions that could be attached to polymers. Combined with at least five backbones that have low Tg, there are thousands of possible combinations. Furthermore, he is a co-PI on a seven-PI Army MURI aiming to synthesize ionomer membranes for actuators, which additionally have flexibility in the choice of cation. The intellectual merits of this research are two-fold: (1) The proposed research will suggest anion, polar side group, backbone combinations worthy of synthesis and directly aid the seven synthesis students on the two teams mentioned above. (2) Ab initio calculations can be rapidly applied to a wide variety of anions and cations in different polar media, enabling a detailed understanding of ion interactions and solvation by polar groups, which should propel our modeling efforts with Sanat Kumar at Columbia. The broader impacts of our proposed research are three-fold. (1) The understanding of how to design ionomers for improved ion-conduction will not only impact advanced lithium batteries and actuators, but is also vital for other battery membranes (such as commercial ones transporting F-) and the membrane electrode assemblies for fuel cells. All ion-conducting membranes suffer from the fact that only a tiny fraction of counter-ions participate in conduction, and the proposed research directly addresses boosting the conducting ion content. (2) Materials development in the energy field is expected to play a very important role in the future of the United States economy and way of life. (3) Graduate students trained in this "energy materials" arena will be in enormous demand in both US industry and academia for at least the next ten years. Penn State has superb undergraduates and research motivates them to attend graduate school (15 of 25 undergraduate researchers in the PI's group over the past 14 years have gone on to graduate school in science and engineering) with many current undergraduates interested in "energy materials", including current REU-funded student Daniel King, a Materials Science and Engineering junior who has won our department's Undergraduate Research Fellowship for three consecutive years.

0933391ColbyCurrent锂电池使用填充有溶解在高介电常数溶剂中的锂盐的纳米多孔聚丙烯膜作为电极之间的隔膜。无论选择何种阴离子，该技术都存在安全问题，阴离子的移动速度比 Li+ 快 5-10 倍，导致阴离子在电极处积聚，从而显着降低电池效率、最大电池功率和充电时间。替代膜的明显选择是单离子导电聚合物（离聚物），其所有阴离子均与聚合物共价键合，没有溶剂从电池中泄漏，并且可以轻松制成薄膜。不幸的是，最好的离聚物膜的 Li+ 离子电导率对于实际应用而言太小 100 倍。该 PI 领导着一个由美国能源部 (DOE) 资助的 5 名 PI 团队，该团队正在尝试设计用于锂电池膜的优质离聚物，但也面临着非常广阔的设计空间，其中有 30 个极性基团可以作为侧链添加，20 个阴离子可以连接到聚合物上。与至少五个具有低 Tg 的主链相结合，有数千种可能的组合。此外，他还是七 PI 陆军 MURI 的联合 PI，旨在合成用于执行器的离聚物膜，该膜在阳离子选择方面也具有灵活性。 这项研究的智力价值有两个方面：（1）拟议的研究将提出值得合成的阴离子、极性侧基、主链组合，并直接帮助上述两个团队的七名合成学生。 (2) 从头计算可以快速应用于不同极性介质中的各种阴离子和阳离子，从而能够详细了解极性基团的离子相互作用和溶剂化作用，这将推动我们与哥伦比亚大学 Sanat Kumar 的建模工作。我们提议的研究具有三重更广泛的影响。 (1) 了解如何设计离聚物以改善离子传导不仅会影响先进的锂电池和执行器，而且对于其他电池膜（例如传输 F- 的商用电池膜）和燃料电池的膜电极组件也至关重要。所有离子传导膜都面临这样一个事实：只有一小部分反离子参与传导，而拟议的研究直接解决了提高传导离子含量的问题。 （2）能源领域的材料发展预计将对美国未来的经济和生活方式发挥非常重要的作用。 (3) 至少在未来十年内，美国工业界和学术界都对“能源材料”领域培养的研究生有巨大的需求。宾夕法尼亚州立大学拥有优秀的本科生，研究激励他们进入研究生院（过去 14 年 PI 小组的 25 名本科生研究人员中，有 15 名进入了科学与工程研究生院），许多本科生对“能源材料”感兴趣，包括当前 REU 资助的学生 Daniel King，他是材料科学与工程大三学生，连续三年获得了我们系的本科生研究奖学金。