NSF-DFG CONFINE: Lithium ion transport in self-assembled zwitterionic nanochannels containing ionic liquids

NSF-DFG CONFINE：含有离子液体的自组装两性离子纳米通道中的锂离子传输

• 批准号: 2234243
• 负责人: Ayse Asatekin
• 金额: $ 51.7万
• 依托单位: Tufts University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2025-09-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2234243&HistoricalAwards=false
• 关键词: NSF; DFG; CONFINE; Lithium; ion

Next generation energy storage systems such as lithium metal batteries are crucial for the broader use of renewable energy resources and mobile energy. Their success relies on the development of advanced electrolyte materials that quickly and selectively conduct the target ion (e.g. Li+) while also providing robust mechanical properties. Self-assembling polymers that confine the conducting ions into nanometer-scale domains while providing a robust structure can potentially enable such materials. This type of electrolyte, however, has achieved only limited ionic conductivity levels to date. This project aims to understand how ions travel within specialty polymers that self-assemble to form zwitterionic nanometer-scale domains that can be preferentially swollen with ionic liquids. We expect that these findings will open the door to new, better-performing electrolytes for energy storage applications.The aim of this project is to study Li+ ion transport within zwitterionic (ZI) conducting nanochannels formed by the self-assembly of amphiphilic comb copolymers. To ensure sufficiently high ionic conductivity at ambient temperatures, the ZI-rich channels will be swollen with controlled amounts of a nonvolatile ionic liquid (IL) containing a dissolved Li salt. The resulting materials are referred to as nanostructured electrolytes (NSEs). The primary objective of this study is to test the hypothesis that confinement into nanochannels decorated with weakly interacting ZI interfaces will selectively enhance Li+ ion transport within NSEs. The proposed experimental plan is designed to examine the effect of ZI side-groups on Li+ ion transport as the IL-swollen nanochannels size (i.e. channel diameter of the conducting domain) inside a NSE is systematically modulated. Modulation of confinement will be achieved by carefully tuning: (i) copolymer architecture, (ii) degree of IL swelling, and (iii) rigidity of the structural domain. Overall ion transport in NSEs will be characterized by AC impedance spectroscopy and DC polarization measurements used to determine Li+ transference number values. Diffusion of individual ion species will be probed using 7Li, 19F, and 1H pulsed field gradient NMR spectroscopy. Electrophoretic NMR (eNMR) spectroscopy will be applied to NSEs for the first time to measure selective Li+ conduction directly. Physical characterization of NSEs will include DSC, TEM, SAXS/WAXS, and rheology. The proposed NSEs featuring ZI conducting nanochannels are expected to provide a valuable new strategy for electrolyte materials design to realize an enhancement of targeted ion transport within electrochemical energy storage systems.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.

锂金属电池等下一代储能系统对于更广泛地使用可再生能源和移动能源至关重要。他们的成功依赖于先进电解质材料的开发，这些材料能够快速、选择性地传导目标离子（例如 Li+），同时还提供强大的机械性能。自组装聚合物将导电离子限制在纳米级域内，同时提供坚固的结构，有可能使这种材料成为可能。然而，迄今为止，这种类型的电解质仅实现了有限的离子电导率水平。该项目旨在了解离子如何在特种聚合物内移动，这些聚合物自组装形成两性离子纳米级域，这些域可以优先被离子液体溶胀。我们期望这些发现将为能量存储应用打开新的、性能更好的电解质的大门。该项目的目的是研究由两亲性梳形共聚物自组装形成的两性离子（ZI）导电纳米通道内的Li+离子传输。为了确保在环境温度下具有足够高的离子电导率，富含 ZI 的通道将用受控量的含有溶解的锂盐的非挥发性离子液体 (IL) 来膨胀。所得材料被称为纳米结构电解质（NSE）。本研究的主要目的是测试这样的假设：限制在用弱相互作用 ZI 界面装饰的纳米通道中将选择性地增强 NSE 内的 Li+ 离子传输。所提出的实验计划旨在检查 ZI 侧基对 Li+ 离子传输的影响，因为 NSE 内的 IL 膨胀纳米通道尺寸（即导电域的通道直径）受到系统调节。限制的调节将通过仔细调整来实现：(i) 共聚物结构，(ii) IL 膨胀程度，以及 (iii) 结构域的刚性。 NSE 中的总体离子传输将通过交流阻抗谱和直流偏振测量来表征，用于确定 Li+ 迁移数值。将使用 7Li、19F 和 1H 脉冲场梯度 NMR 光谱来探测各个离子种类的扩散。电泳核磁共振 (eNMR) 光谱将首次应用于 NSE，直接测量选择性 Li+ 传导。 NSE 的物理表征包括 DSC、TEM、SAXS/WAXS 和流变学。所提出的具有 ZI 导电纳米通道的 NSE 预计将为电解质材料设计提供有价值的新策略，以实现电化学储能系统内目标离子传输的增强。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准。