My research is inspired by chemical, material, and engineering challenges that underlie critical problems

in sustainability and energy science

Fields

1) Coupled Ion-Electron Transfer in Energy Science

Lithium ion (Li-ion) batteries, which power our modern lifestyles, are one prime example of this - Li ions transfer is coupled with the electron transfer to store and release energy; Another example is proton-coupled electron transfer, which is essential to a variety of chemical and biological processes, including photosynthesis and enzyme reactions.
One of the dreams in electrochemistry is to understand reaction pathways and transport kinetics and thus control coupled ion-electron transfer on interface and in bulk for energy applications.
I have exemplified this approach with new mechanisms that govern the degradation and diagnosis of Li-ion batteries (Science, 2024) and structural transformation of catalytic materials (Science Advances, 2021).

2) Crossroads of Thermo-, Photo-, Electro-chemical Reactions for Sustainability

Chemical transformations can be driven with a variety of energy inputs (e.g., heat, light, and electrochemical potentials). Current energy transitions toward sustainability require all these approaches. How to integrate and optimize these approaches in effective ways remains a grand challenge.
On the other hand, much attention has been paid to active sites (catalysts) (e.g., Advanced Materials, 2020; ACS Catalysis 2022). Despite this, we have not given active species the attention they deserve.
One solution is to understand and control the active species (e.g., free radicals, intermediates) that are involved in these reactions and thus build the intersections among them (e.g., to accelerate reaction rates, one thermochemical reaction can benefit from the enhanced transport of active species, such as protons and superoxide anions, using electrostatic potentials; to improve selectivity towards desired products, one photochemical reaction can be paired with another thermocatalytic process).
One of the dreams is to apply these fundamental chemical engineering concepts and methodologies to unlock this new era of active species in chemical transformations. Doing so, we can bridge the gaps between engieering science and sustainability.

3) Nonequilibrium Phase Transitions and Amorphization Mechanisms

The physical process of transitions between different states is ubiquitous. Examples include melting, freezing, and condensation; Another example is the transitions of carbon (e.g., from the three-dimensional network bonding structure of diamond to the two-dimensional sheet-like bonding structure of graphite).
The condition known as equilibrium occurs when there is no net change and all process forward rates and reverse rates are equal. At equilibrium, we can say a great deal about what is possible, about the states of matter and energy, and about the structures that arise. However, change is not always followed by equilibrium.
My research aims to gain an equal understanding of phase transitions that occur far away from equilibrium. Specifically, one key theme of my research centers on uncovering mechanims that govern order-to-disorder transtions and amorphiziation processes in energy materials and thus unlock bottlenecks.
My research has exemplified this with oxide-based electrocatalysts that are key for electrosynthesis (e.g., green hydrogen) (Science Advances, 2021), and organic-inorganic hybrid materials for energy conversion, as well as intermittent behaviors of point defects (e.g., oxygen vacancies) (Advanced Materials, 2023).

4) Synchrotron Radiation Techniques as a Unique Lens in Physical Science

Over the past century, synchrotron X-rays have allowed us to see things that were previously unseeable, and their impacts on physical sciences are well-established.
More X-ray probes (e.g., core-level spectroscopy and X-ray scattering) have been made available in synchrotron sources and even in laboratories, and advanced X-ray methods have adopted in-situ capability.
Specifically, in-situ X-ray probes and synchtron-based techniques that are sensitive to heterogeneities and dynamics (with improved spatial and temporal resolutions) can provide a unique view into the nano-wonderland in energy materials.
My research has examplied this with the transformation of catalytic materials (Nature Catalysis, 2023; Accounts of Chemical Research 2021; ACS Catalysis 2022) and the measurement of equilibrium density fluctuations in neuromorphic materials (Advanced Materials, 2023).

5) Physical Chemistry of Solids

Solid state reactions involving defects are not only vital for and during the formation of our planet, but they also constitute a large portion of the processes taking place now in nature and in laboratories and factories.
Thus, my research aims to understand the chemistry and physics of defects in energy science (e.g., electrochemical devices, catalytic reactors) and climate technologies, especially in response to external stimulli (e.g., light illumination, electrochemical potentials). Specifically, one intriguing opportunity lies in the intersection of solid state ionics and interfacial chemistries.

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