Atomic-Level Insights into Battery Systems: From Nuclear Magnetic Resonance (NMR) to Electron Paramagnetic Resonance (EPR)
Solid-state nuclear magnetic resonance (NMR) spectroscopy is an atomic-level method to determine the chemical structure, 3D structure and dynamics of solids and semi-solids. NMR is particularly useful for studying the local environments of nuclei in materials, including lithium ions in battery electrodes. EPR, on the other hand, is used to study the spin properties of unpaired electrons in materials, providing information on the electronic structure and redox reactions that occur in battery systems. These advanced spectroscopic techniques provide valuable information on the atomic-scale structure and dynamics of battery materials. By combining these techniques with other advanced characterization methods, I can gain a deeper understanding of the fundamental processes that govern battery performance and develop more efficient and sustainable energy storage solutions.
I incorporate advanced characterization methods to obtain atomic-level insights into the mechanisms of operation and degradation in battery systems. I synthesize and manufacture new materials, perform electrochemistry, and employ state-of-the-art multimodal atomic-level tools, including solid-state nuclear magnetic resonance (SS-NMR) spectroscopy, pulsed-field gradient nuclear magnetic resonance measurements (PFG NMR), electrophoretic NMR (eNMR), magnetic resonance imaging (MRI), dynamic nuclear polarization (DNP) spectroscopy, X-ray diffraction, and X-ray spectroscopy/imaging techniques (XAS, XANES, EXAFS, computed micro-tomography, XRF), as well as high-resolution X-ray and neutron diffraction. Our unique solid-state NMR instrumentation spans 700 MHz, 500 MHz, and 400 MHz superconducting magnets with Bruker spectrometers and an array of new probes from Phoenix NMR. To complement our experimental work, we also conduct electronic structure calculations and numerical simulations, working closely with simulation collaborators and national labs.
In addition to state-of-the-art NMR and EPR, I have access to a range of other techniques, such as X-ray synchrotron studies, neutron diffraction, infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray photoelectron (XPS) spectroscopy, advanced cryogenic electron microscopy (Cryo-EM), cryogenic Focused Ion Beam SEM (Cryo-FIB-SEM), gas chromatography, and mass spectrometry. These complementary methodologies offer unique information on battery systems and help to further deepen our understanding of these complex systems.
Atomic-Scale Materials and Manufacuturing for Clean Energy
Single-atom catalysts (SACs) offer controllable coordination environments and exceptional atom utilization efficiency, revolutionizing the design of high-performance, sustainable catalysts. Aided by recent advances in practical synthetic methodologies, characterization techniques, and computational modeling, I have built single-atom catalysts (SACs) that exhibit distinctive performances for a wide variety of chemical reactions. I have also invented several synthetic methodologies and developed advanced atomic-resolution characterization techniques, such as S/TEM atomic resolution imaging, electron energy loss spectroscopy (EELS), X-ray spectroscopy/microscopy, and synchrotron-XAS/Micro-CT/SAXS techniques, as well as using density-functional theory (DFT) for atomically precise materials. Atomically dispersed metals that I invented have been applied to electrochemical interfaces.
