(6bb) Combining Theory and Experiment at the Electrode/Electrolyte Interface to Improve Electrochemical Energy Conversion and Storage

2^nd
Year Post-doctoral Fellow

Post-doctoral
project: “Combining
experiment and atomistic scale computational modeling to study the
electrode-electrolyte interface”
under the supervision of Dr. Marc Koper, Leiden Institute of Chemistry, Leiden
University

Ph.D.
Dissertation: “Understanding
the effects of electrolyte pH and spectator ions on electrocatalysis” under
the joint supervision of Dr. Michael Janik and Dr. Michael Hickner, Department
of Chemical Engineering, Pennsylvania State University

Awarded
proposals: Leading
Fellows (Marie Curie COFUND) Post-doctoral Fellowship, EU, 2018; Teaching
Fellowship, The Pennsylvania State University, 2015; EPA P3 Awards, US EPA, 2009
(“Farm Waste to Energy: A Sustainable Solution for Small-Scale Farms”)

Research
Interests:

            I
am interested in combining detailed electrochemical experiments and atomistic
scale computational modeling to study the electrochemical interface. With these
methods I will improve our fundamental understanding of electrochemistry and
electrocatalysis, as well as develop high performance and low cost energy
storage and conversion processes and devices, including batteries and fuel
cells.

            I began academic research as an undergraduate under Dr. Stefan
Grimberg at Clarkson University, where I used both experiment and continuum
scale modeling (in MATLAB/Simulink) to probe the effects of staging on the
energy efficiency and cost of anaerobic digestion. I further pursued
computational modeling under Dr. Michael Janik at the Pennsylvania State
University during my Ph.D. in Chemical Engineering, where I learned how to
perform density functional theory (DFT) calculations for studying electrocatalysis.
I gained an expertise in finding computationally efficient methods to examine
the effects of solvation, electrolyte ions, and pH on surface chemistry relevant
to fuel cells and electrolysis. I was co-advised by Dr. Michael Hickner, under whom
I gained additional skills in performing my own electrochemistry experiments,
using cyclic voltammetry to measure reaction kinetics. We made an explicit
effort to directly compare our computational results to experiment.  

            I am continuing to combine experiment and density functional theory
modeling during my current post-doctoral work with Dr. Marc Koper at Leiden
University in the Netherlands. I perform DFT-based kinetic modeling, as well as
detailed electrochemistry experiments, particularly with well-defined single-crystal
electrodes. We have shown that not only does the catalyst surface exhibit a
significant effect on (electro)catalysis, but the solvent, ions, and pH near
the electrode surface also play a significant role in dictating reaction rates
and mechanisms. The unique combination of atomistic scale modeling and
experiments with well-defined electrodes gives us a mechanistic understanding
of the behavior of the electrode/electrolyte interface that would be difficult
to obtain with either technique alone.        

            Over the past four years, I have published 9 peer-reviewed articles
(7 first authored) and have recently submitted an additional 5 manuscripts.

Future
Research Directions:

1)
Benchmarking near-surface solvation models and determining the surface
structure/composition of real catalysts in the electrochemical environment. In our prior work, we have used
computationally efficient methods to approximate the effects of solvation on
the thermodynamics of adsorption of many species, including hydrogen,
hydroxide, oxygen, and the halide anions to complex surfaces, and have shown
these thermodynamics match experiment. While many techniques have been
evaluated for approximating the effects of solvation of the adsorption of more
complex species, these adsorption thermodynamics are only rarely compared
directly to experiment. I will use density functional theory and experimental
cyclic voltammetry measurements with single crystal electrodes to examine the
adsorption of many neutral and ionic species to evaluate and benchmark methods
of approximating the effects of solvation. These methods include explicit,
implicit, and combined explicit/implicit solvation methods. By systematically
evaluating the role of the surface structure and the properties of the
adsorbate (charge distribution, dipole moment, polarizability) we will
determine which methods are best suited for predicting thermodynamics and
kinetics in the electrochemical environment, even for adsorbates whose
adsorption thermodynamics we cannot directly measure (such as for short-lived
reaction intermediates). This work will also allow us to examine the stability
of a wide array of different surface facets/steps/defects in the presence of
adsorbed electrolyte or reactive species, which have a strong effect on
catalyst stability. With these surface structure stabilities, we can determine
the preferred size, shape, and surface composition of real, complex metal
catalysts in the electrochemical environment.

2)
Improved catalysts and processes for the electrochemical synthesis of organic
compounds. While
significant study has been devoted to organic electrochemistry, and some
electrochemical synthesis methods are utilized industrially to produce complex,
high-value organic compounds, most of these electrochemical processes have been
identified by trial-and-error, and catalysts for these reactions remain
under-optimized (in terms of activity, selectivity, and cost). Significant
scientific research has been devoted to understanding the electroreduction of
carbon dioxide to valuable fuels and chemicals, however, given the complexity
and high energy requirements, it is unclear if or when such a process will see
commercial use. I will use density functional theory and experiment to better
understand structure-activity-selectivity relationships for the electrochemical
reduction/oxidation of biomass derived organic compounds (which lie
energetically closer to their desired products than carbon dioxide) to
high-value chemicals.

3) Bulk, surface, and solution
phase properties of electrode materials for both ion-intercalation and redox
flow batteries. A wide variety of both inorganic and organic compounds have
been investigated for use as energy storage components (anodes/cathodes) in
lithium-ion (or other alkali-/alkali earth- metal ion) and redox flow batteries.
The solubility of the active components plays an important role in each
battery; in an ion-intercalation battery high solubility is undesirable as it
leads to poor cyclability, where in redox flow batteries, high solubility is
desirable as it leads to high energy and power density. I will use both density
functional theory as well as experimental half-cell and whole-cell battery
cycling and cyclic voltammetry to examine how the bulk, surface, and solution
phase properties of active electrode materials affect their solubility and performance.
I am particularly interested in organic active materials, many of which have
high capacities and low cost. Altering the molecular structure will allow us to
change both the solution phase properties (how the organic compound interacts
with the solvent) and the solid-state properties (the crystal structure and
binding energy). This will lead to the development of improved active materials
for both ion-intercalation and redox flow batteries, suitable for low-cost,
grid-scale energy storage.

Teaching
Interests:

My
previous teaching and research experiences have well prepared me to teach much
of the core Chemical Engineering coursework, including thermodynamics, reaction
engineering/kinetics, heat transfer, unit operations, and laboratory exercises.
While an undergraduate at Clarkson University, I tutored junior and senior
students in process modeling and control. While a graduate student at The
Pennsylvania State University, I served as both a teaching assistant and
instructor (as a teaching fellow) for CHE480W (“Chemical Engineering
Laboratory”). As a teaching fellow I was responsible for holding office hours;
evaluating, grading, and giving detailed feedback on written technical reports
and oral presentations; and for helping students to better understand all of
the core chemical engineering principles necessary to carry out the experiments
in CHE480W, covering topics ranging from fluid mechanics, mass transport, heat transfer,
and unit operations including distillation and liquid-liquid extraction. I have
additionally given seminars about the use of atomistic scale (quantum mechanics
based) modeling for electrochemistry, surface science, and catalysis. I would
like to create a course for undergraduate or graduate students on the use of
these ab-initio modelling techniques in chemical engineering. I am passionate
about teaching students and am excited to contribute to their future success as
chemical engineers in both industry and academia.