We research new materials and work to understand their properties for next-generation energy storage and conversion systems.
The overarching goal of the group's research is to understand how materials behave and transform in real-life environments within energy devices, which will enable us to engineer improved materials for new energy technologies.
The importance of observing dynamic Processes
In energy devices (for example, batteries, fuel cells, photocatalytic systems, and electrolyzers), mass transport, high temperatures, reactive environments, and mechanical stresses are the norm. Materials in these systems are not static; instead, they often change, transform, or degrade in response to these operating conditions.
Our research group focuses on using in situ experimental techniques to probe materials transformations under realistic conditions, and we seek to understand how such changes influence properties. These fundamental scientific advances guide the engineering of materials for breakthrough new energy devices.
Students and other researchers in the group synthesize materials, analyze their properties, and utilize a variety of in situ characterization methods to understand dynamic structure and chemistry. This information is then understood in the context of the material’s behavior within devices.
1. Phase transformation mechanisms in next-generation battery materials
Next-generation batteries require materials with higher charge storage capacity, or they require the development of new materials for entirely new battery systems beyond lithium-ion (for example, sodium-ion or multi-valent batteries). The reaction and phase transformation mechanisms of new materials determine how much charge they can store and how long they last within batteries.
Thus, it is critical to understand these reaction mechanisms across multiple length scales (from the atomic scale to the mesoscale) within battery electrodes. We use powerful in situ experimental techniques, including transmission electron microscopy, x-ray diffraction, and x-ray spectroscopy methods, to reveal structural, chemical, and morphological transformations in real time.
2. Controlling mass transport and transformations at interfaces
It is critical to understand and control processes at solid-solid and solid-liquid interfaces when using nanomaterials in energy applications (as well as many other applications). This is due to the prevalence of interfaces, and to their divergent structure, chemistry, and properties compared to the bulk.
Our group is working on understanding how anisotropic atomic structure influences mass transport at interfaces, and we are also working on controlling interfaces in solid-state batteries.
3. Degradation in electrocatalysts
Certain electrocatalysts for the electrochemical production of fuels undergo near-surface structural and chemical changes during operation. These changes alter materials properties and also likely induce the evolution of mechanical stress. To engineer improved electrocatalytic materials, it is necessary to fully understand these phenomena and their effects on electrochemical properties.