Aqueous Organic Redox-Flow Batteries. Greater adoption of intermittently available renewable (e.g., solar and wind) power critically depends on our ability to store large amounts of electricity at low cost. We study water-soluble organic molecules as energy carriers in redox-flow batteries for long-duration, grid-scale energy storage. Our main objective is to understand and mitigate the decomposition processes these materials undergo in order to design and test more resilient chemistries. These investigations are interdisciplinary and collaborative, involving operando spectroscopy, physics-based modeling, statistical inference, atomistic simulations, machine learning and organic synthesis. Ultimately, we hope to enable closed-loop generation and testing of optimal molecules through tight integration of theory, experiment, modeling, and synthesis. 

Carbon Dioxide Capture and Resource Recovery. The selective and energy-efficient removal of substances from the environment is an important challenge in environmental sustainability. This need arises in applications such as: capture of carbon dioxide from the atmosphere to mitigate climate change, desalination of water sources, recovery of nitrogen- and phosphorus-based nutrients from aquatic systems, and extraction of critical elements from industrial waste streams. We are interested in developing chemical reactors that enact these separation processes using redox-mediated ion transport, and reversible pH swings driven by light-modulated acid-base chemistry (e.g., in metastable photoacids and photobases) and proton-coupled electron transfer.

Nanomaterials and Ceramic Ion Conductors for Energy and Environment. The emergence of electroactive nanomaterials with high charge storage capacities, and highly conductive ceramic ion conductors creates the opportunity to enable new chemistries and configurations for energy and environmental applications. A recent area of interest is the use of suspensions of metal chalcogenide nanoparticles in redox-flow batteries, which has the potential to exceed charge densities of traditional flow batteries with dissolved molecular charge carriers. Our main objectives are to understand: (1) electron-transfer and phase conversion reactions at the single-particle level using single-entity electrochemical techniques, (2) rheological properties of these suspensions  under conditions relevant to battery operation, and (3) the role conformal particle coatings can play in mitigating degradation. A second area is the use of sodium superionic conductors (NaSICONs) in flow cells for energy storage, carbon capture and desalination. Here, we wish to develop and deploy reactors with low area-specific resistance by understanding and mitigating chemo-mechanical degradation at the interface between the solid membrane and liquid electrolyte.