Energy materials based on single-ion conducting polymers mixed with zwitterions

非技术总结：新材料在能源领域的应用需要一种且只有一种离子的最大导电性。这项关于聚合物能量材料的离子传导和介电常数的研究旨在了解仅传导一种离子的聚合物的结构-性质关系，例如用于先进电池的锂，以及用于超级电容器、传感器和机械执行器的更大的移动离子。增加导电离子移动性的一种方法是在单离子导电聚合物中加入“两性离子”，这是一种含有正电荷和负电荷的小分子。虽然在聚合物材料中添加两性离子的方法已经显示出前景，但为了未来的应用，需要设计具有特定功能的材料。如果成功，从这项研究中产生的基础知识将导致对设计各种特定能源应用所需的聚合物材料的理解，包括先进的电池、燃料电池、太阳能电池、离子致动器、超级电容器和能量收集设备（每一个都需要最大化离子传输）。每一项应用都有可能改变当前的技术，改善全球人类的生活。该项目还将为研究生和本科生提供先进的科学培训和接触跨学科研究的机会，以及外展的机会。技术概述：离聚体是一类重要的能源材料，用于需要单离子传导的应用，但它们的结构-性质关系才刚刚开始探索。在这项研究中，三种新型材料正在被制造出来：(1)具有导电反阴离子的高分子量聚阳离子，即均聚物、无规共聚物和二嵌段共聚物；(2)具有导电反阳离子的高分子量聚阴离子，即均聚物、无规共聚物和二嵌段共聚物；(3)极性小分子两性离子，它们是两种离子聚物的非挥发增殖剂，以提高离子电导率。一个关键的基本问题是如何通过仔细的分子设计来优化离聚体和两性离子的混合物。如果成功，本研究将揭示离子与两性离子协同设计的设计规律。通过充分了解这些材料的介电响应（包括介电常数和离子电导率的温度依赖性），并使用x射线散射来详细描述它们的形态，将详细了解这些混合物中两性离子结构的系统变化的影响。通过探索两性离子的离子含量、反离子类型和极性（介电常数）的参数空间，可以确定这类能源材料在最高可能介电常数和离子电导率方面的势能。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL SUMMARY: Applications that will be enabled by new materials in the energy arena simultaneously require maximal conductivity of one and only one type of ion. This research on ion conduction and dielectric constant of polymeric energy materials aims to understand the structure-property relations in polymers that conduct only one type of ion, such as lithium for advanced batteries and perhaps larger mobile ions for supercapacitors, sensors, and mechanical actuators. A way to increase the mobility of the conducting ions is to add "zwitterions", which are small molecules containing both positive and negative charges, to single-ion conducting polymers. Although the method of adding zwitterions to polymeric materials has shown promise, fundamental insight is needed to design materials for specific functions for future applications. If successful, the fundamental knowledge generated from this research will result in the understanding needed to design polymeric materials for a variety of specific energy applications, including advanced batteries, fuel cells, solar cells, ionic actuators, supercapacitors, and energy harvesting devices (each of which require maximizing ion transport). Each of those applications has the potential to change current technologies and improve the lives of humans across the globe. This project will also provide advanced scientific training and exposure to interdisciplinary research to graduate and undergraduate students, as well as opportunities for outreach.TECHNICAL SUMMARY: Ionomers are an important class of energy materials for applications that require single-ion conduction, yet their structure-property relations are only beginning to be explored. In this research, three novel types of materials are being made: (1) High molecular weight polycations with conducting counter-anions that are homopolymers, random copolymers and diblock copolymers, (2) high molecular weight polyanions with conducting counter-cations that are homopolymers, random copolymers and diblock copolymers, and (3) polar small molecule zwitterions that are non-volatile plasticizers for both types of ionomers to boost ionic conductivity. A key fundamental question is how mixtures of ionomers and zwitterions can be optimized by careful molecular design of the two. If successful, this research will reveal the design rules for the codesign of ionomer and zwitterion. By fully understanding the dielectric response of these materials (including the temperature dependence of dielectric constant and ionic conductivity) and using X-ray scattering to detail their morphology, the effects of systematic variations in zwitterion structure in such mixtures will be understood in detail. By exploring the parameter space of ion content, counterion type and polarity (dielectric constant) of the zwitterion, the potential of this class of energy materials, in terms of highest possible dielectric constant and ionic conductivity, will be determined.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.