In order to develop new materials for energy storage and conversion, we must first understand the relationship between material structure and performance. Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool to simultaneously identify changes in material structure and dynamics during operation. We leverage insight from NMR, MRI, and traditional materials characterization tools (diffraction, scattering, and electron microscopy) to understand both performance degradation as well as performance enhancement in Li- and beyond-Li-ion batteries as well as other novel material platforms. Our current research focuses on four main areas:
We aim to characterize the composition and arrangement of compounds at electrode/electrolyte interfaces. While these interfaces and interphases represent only a small proportion of the material in a battery, they play a key role in degradation during electrochemical cycling. We use a combination of traditional solid-state NMR and dynamic nuclear polarization (DNP) NMR to characterize interphase chemistry on both the anode and cathode sides of Li ion batteries.
Measuring ion movement and diffusion in multiphase devices, such as batteries, is challenging due to resolution and the differences in diffusivity in the solid and liquid phases. We use NMR to understand ion transport at electrode/SEI/electrolyte interfaces and correlate these measurements with electrochemical behavior.
Next Generation Chemistries
Earth abundant alkali metals, such as Na and K, have the potential to reduce the cost of Li ion batteries and offer potentially new applications for electrochemical energy storage. Our group is exploring fundamental structure-performance relationships in these emerging chemistries.
In Situ Characterization
In situ and operando NMR/MRI characterization captures key kinetic intermediates and dynamic processes that are impossible to measure ex situ. Our group uses in situ electrochemical and light NMR/MRI to understand changes in structure and dynamics during device operation for applications in energy storage and conversion.