In situ NMR spectroscopic investigations of ion adsorption mechanisms on nanoporous carbon materials

纳米多孔碳材料由于具有高导电性、高化学稳定性和热稳定性等优异的材料性能，特别是具有较大的电解液可及内表面，因此在电化学储能方面受到越来越多的关注。核磁共振波谱方法越来越有助于理解电池和电极材料中的分子过程。除了材料和表面表征外，核磁共振光谱研究还可以研究电极材料和电解液分子之间的相互作用。同时，这甚至可以通过带电设备的原位核磁共振波谱来实现。在本项目中，将合成具有典型孔径分布和表面功能的定义明确的理想化模型材料，用于识别吸附离子的特征核磁共振特征。与创新的原位表征技术相结合，这将导致关于电吸附过程中发生的分子过程的详细机制结论。计划中的研究包括：(I)具有定制的孔径和表面功能的已定义的模型材料的制备和表征(例如，具有单一或多模孔尺寸分布的碳材料，具有或不具有极性表面功能化等)。(2)固体核磁共振波谱表征碳材料表面与电解液分子之间的相互作用，有无外加电压。(Iii)用定量液态核磁共振波谱分析孔填充机理(吸附等温线)。此外，还将深入了解动力学和吸附动力学。对这些分子机理的理解将有助于为超级电容和其他电化学储能装置的改进电极的制备提供合理的设计原则。

Nanoporous carbon materials have gained increasing interest for electrochemical energy storage due to their outstanding materials properties such as high electrical conductivity, chemical and thermal stability, and especially due to their large electrolyte-accessible internal surfaces. NMR spectroscopic methods increasingly contribute to the understanding of the molecular processes in battery and electrode materials. In addition to materials and surface characterization, NMR spectroscopic studies also allow investigating the interactions between electrode materials and electrolyte molecules. Meanwhile, this can be even done by in situ NMR spectroscopy of charged devices. Within the present project, well-defined, idealized model materials with typified pore size distributions and surface functionalities will be synthesized for the identification of characteristic NMR signatures of adsorbed ions. Combined with innovative in situ characterization techniques, this will lead to detailed mechanistic conclusions concerning the molecular processes taking place during electro-adsorption. The planned investigations include: (i) Preparation and characterization of defined model materials with tailored pore sizes and surface functionalities (e.g., carbon materials with mono- or multimodal pore size distribution, with or without polar surface functionalization etc.). (ii) Solid-state NMR spectroscopic characterization of the interactions between the surface of the carbon materials and electrolyte molecules with and without applied voltage. (iii) Analysis of the pore filling mechanisms (adsorption isotherms) using quantitative liquid-state NMR spectroscopy. Moreover, insights into dynamics and adsorption kinetics will be gained. The understanding of these molecular mechanisms will contribute to derive rational design principles for the fabrication of improved electrodes for supercaps and other electrochemical energy storage devices.