Lithium ion transport in self-assembled zwitterionic nanochannels containing ionic liquids

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: 509154483
• 负责人: Professorin Dr. Monika Schönhoff
• 金额: --
• 依托单位: Institut für Physikalische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/509154483?language=en
• 关键词: Lithium; ion; transport; self; assembled

Next-generation electrochemical energy storage technologies, such as lithium metal batteries, will require advanced electrolyte materials. These electrolytes should promote fast, selective conduction of a target ion (e.g. Li+) while also providing robust mechanical properties to inhibit dendrite growth and eliminate electrolyte leakage. Copolymer self-assembly, which can facilitate the spontaneous formation of interpenetrating structural domains and conducting domains from two chemically distinct monomers, is a powerful tool for realizing such materials. However, confined salt-in-copolymer only electrolytes have so far largely failed to reach the levels of ionic conductivity that are necessary for practical applications. Bicontinuous structures that exhibit conducting nanochannels are especially attractive, as unique interfacial effects between the two domains that may promote selective ion transport can be exploited. 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 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) in 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. While this study will focus on Li+ transport, such NSE materials may also provide a platform for enhancing the transport of other cations (Na+, H+) and/or anions in other applications such as “beyond-lithium” batteries and fuel cells.

下一代电化学储能技术，如锂金属电池，将需要先进的电解质材料。这些电解质应促进目标离子（例如Li+）的快速、选择性传导，同时还提供稳健的机械性能以抑制枝晶生长并消除电解质泄漏。共聚物自组装是实现这类材料的有力工具，它可以促进两种化学性质不同的单体自发形成互穿结构域和导电域。然而，受限的仅共聚物包盐电解质迄今为止在很大程度上未能达到实际应用所需的离子电导率水平。表现出导电纳米通道的双连续结构是特别有吸引力的，因为可以利用两个域之间的独特界面效应来促进选择性离子传输。本项目的目的是研究锂离子在两性梳型共聚物自组装形成的两性离子（ZI）导电纳米通道中的传输。为了确保在环境温度下足够高的离子电导率，富含ZI的通道将用受控量的含有Li盐的非挥发性离子液体（IL）溶胀。由此产生的材料被称为纳米结构电解质（NSE）。本研究的主要目的是测试的假设，约束到装饰与弱相互作用ZI接口的纳米通道将选择性地增强锂离子运输NSE内。所提出的实验计划被设计为检查ZI侧基对Li+离子传输的影响，因为NSE中的IL溶胀纳米通道尺寸（即，导电域的通道直径）被系统地调制。限制的调节将通过仔细调节以下各项来实现：（i）共聚物结构，（ii）IL溶胀的程度，和（iii）结构域的刚性。NSE中的总体离子传输将通过用于确定Li+迁移数值的AC阻抗谱和DC极化测量来表征。将使用7 Li、19 F和1H脉冲场梯度NMR光谱法探测单个离子种类的扩散。电泳NMR（eNMR）光谱将首次应用于NSE，以直接测量选择性Li+传导。NSE的物理表征将包括：DSC、TEM、SAXS/WAXS和流变学。拟议的具有ZI导电纳米通道的NSE预计将为电解质材料设计提供一种有价值的新策略，以实现电化学储能系统内靶向离子传输的增强。虽然这项研究将集中在Li+运输，但这种NSE材料也可以提供一个平台，用于增强其他阳离子（Na+，H+）和/或阴离子在其他应用中的运输，如“超锂”电池和燃料电池。