IBS CMSD Seminar_Dr. Young Joo Lee (Korea Basic Science Institute, KBSI, 31 May, 2023, Wed)
Seminar
Dr. Young Joo Lee (Korea Basic Science Institute, KBSI)
Solid-state and PFG NMR spectroscopy as a probe for interface structure and dynamics
To develop new materials with desired properties as the new energy systems and catalysts for the green chemical process, fundamental understanding of the materials is necessary. NMR spectroscopy is an ideal tool to get structural and dynamic information of materials. In this presentation, we will show solid-state and pulsed field gradient (PFG) NMR study on various systems such as rechargeable battery and guest molecules confined in mesoporous systems. Solid state NMR spectroscopy is a powerful technique to get information about the interfacial structure and morphology information. We studied periodic mesoporous organosilica with various organic functional groups. By using 2D HETCOR NMR, spatial arrangement of water inside the pores, the interfacial structure at the guest-pore wall, and phase changes from double layers to single monophase is directly probed. Understanding ionic motion of electrolyte in confined space is crucial for the use in various energy storage systems. PFG NMR is a powerful technique to examine the transport motion of individual cationic and anionic species since NMR is sensitive to individual nuclei. We utilize PFG NMR spectroscopy to investigate ionic liquid based electrolyte in porous membrane to study the influence of the nano-confinement and the surface chemistry on the electrolyte motions. In addition, application of NMR to develop new electrolyte system will be discussed.
Figure 1. (left) 2D 1H-29Si and 1H-13C HETCOR NMR spectra of the divinylaniline-bridged periodic mesoporous organosilica (PMO, pore diameter=3.0 nm) of which nanopores are fully filled with water.(right) Schematic representation of the pore filling modes. a) Modulated pore filling b) Uniform pore filling