(6jk) Flowable Slurry Electrodes for Electrochemical Processes

Flowable Slurry Electrodes for Electrochemical Processes

Enoch A. Nagelli
Advisors: Prof. Jesse S. Wainright and Prof. Robert F. Savinell
Department of Chemical and Biomolecular Engineering
Case Western Reserve University

Research Interests:
For majority of the last century, slurry and fluidized bed electrodes have been studied for electrochemical applications such as waste water treatment and energy storage systems. Recently, there has been renewed interest for the use of slurry electrodes in three specific applications: redox flow batteries (RFBs) with flowable slurry electrodes, electrochemical flow capacitors (EFCs), and flow electrode capacitive deionization (FCDI) systems. In order to successfully implement slurry electrodes in electrochemical applications requires fundamental understanding of the factors controlling electronic conduction through the Faradaic and non-Faradaic charge transfer processes occurring during flow. Moreover, recent advances in nanotechnology and materials science offers a selection of metal or carbon particles of any size, geometry and surface area to incorporate as slurry electrodes. Slurry consisting of particles with high surface area and surface to volume ratio can reduce kinetic losses and enhance mass transfer rates, respectively. For example, leveraging the benefits of utilizing slurry electrodes decouples energy storage capacity from power requirements in hybrid flow batteries for achieving low cost energy storage and broad versatility for electrochemical applications. There is also potential for broad applications beyond energy storage such as when processing dilute streams for separation/extraction of ions for chemical treatment and/or when in need of electrode replacement or reprocessing. Therefore, the application of slurry electrodes as a platform electrochemical technology can address environmental concerns, reduce energy costs, and enhance sustainability of many industrial processes.

Postdoctoral Project: ARPA-E Awarded Project - “Large Scale High Energy Capacity All-Iron Flow Batteries”
Under supervision of Professor Robert F. Savinell and Professor Jesse S. Wainright, Department of Chemical and Biomolecular Engineering, Case Western Reserve University

PhD Dissertation: “Controlled Functionalization and Assembly of Graphene Nanostructures for Sensing and Energy Storage Applications”
Under supervision of Professor Liming Dai, Department of Chemical and Biomolecular Engineering, Case Western Reserve University

Awards:
AFRL/DAGSI Ohio Research Fellowship
Project Awarded: “DNA-Directed Self-Assembling of Nanomaterials for Electronics”
Description: Novel chemical modification approach to asymmetrically modify nanomaterials with two different functional groups for supermolecular structures.
Sponsor: Dr. Rajesh Naik, Air Force Research Laboratory, Wright-Patterson Air Force Base, OH

Research Experience:
My graduate and postdoctoral training and research experience have furthered my commitment to pursue a career in academia. I am interested in an academic career that will allow me to expand my research knowledge of organic and inorganic nanomaterials into studying the electrochemical application of these materials in both large and small scale energy storage and conversion devices. My graduate research included the development of novel functionalization and assembly methods for spatial micro- and nanopatterning of carbon nanomaterials in both covalent and noncovalent functionalization schemes crucial for furthering methods of nanolayer assembly of programmable architectures for sensors, flexible electronics, and energy storage. Moreover, my research interests expand across materials science and chemistry of carbon nanomaterials into the electrochemical processes involved in the device applications of these materials. Consequently, my current postdoctoral research focuses on the design, testing, implementation, and electrochemical analysis of redox flow battery systems and the fundamental understanding of electrochemical carbon slurry electrodes for the all-iron redox flow battery. An in-depth understanding of the properties which influence how flowable carbon slurry electrodes create a current distribution that favors plating on the slurry particles is essential for the performance of the all-iron redox flow battery. Currently at CWRU, my research focus is to further understand the influence of physicochemical properties on the electron transfer mechanism and overall conductivity of carbon slurry particles during electrochemical cycling in redox flow batteries.

Teaching Experience:
In addition to my research career, I also have extensive teaching experience as a TA and guest-lecturer in core undergraduate chemical engineering courses (Transport Phenomena and Chemical Reaction Engineering) and measurements laboratory. My duties included guest-lecturing and preparing class material when needed, holding office hours, and grading course materials. As a graduate student and postdoc, I have mentored eleven undergraduate students and five high school students to develop and execute independent research projects by leveraging my lab’s expertise with the student’s own interests.
My time in academia has taught me the importance of fundamental chemical engineering concepts to perceive the balance between theory and practice, analytical rigor and intuition. My teaching interests include undergraduate core chemical engineering courses such as transport phenomena, thermodynamics, chemical reaction engineering, and process control. I would also like to teach graduate level courses in electrochemical engineering, materials for electrochemical energy storage and conversion systems, and carbon nanotechnology.

Future Direction:
My goal is to establish a research program that will continue to contribute to innovative research at the junction of electrochemistry and materials science and engineering. Specifically, I would like to combine the knowledge that I obtained from the research areas that I worked on during my Ph.D. and postdoc to investigate flowable slurry electrodes for electrochemical processes in energy storage and conversion, chemical purification and recovery, and electrode regeneration and protection. My research would be focused on the theory of electron transfer in slurries of particles,
investigations of size, morphology, inherent particle properties, and concentration of particles on effective electronic conductivity, mass transport properties, and stability of the slurry for broad electrochemical applications. Understanding the influence of the intrinsic physicochemical properties of particles on overall conductivity can help predict and design flowable slurry electrodes for specific electrochemical processes. Previous efforts have focused on micron-sized or larger particles in slurry but recent advances in nanotechnology can enable the study and implementation of sub-micron sized particles of different shape, size, and surface area in slurry for electrochemical processes. Thus, the application of slurry electrodes in electroextraction processes can lead to larger range of recovery/extraction of fine organic or inorganic particles from solutions and lower electrode replacement costs for industrial processes.Moreover, incorporating the variety of particles available as flowable slurry electrodes with very high surface area and conductivity can decouple energy and power ratings to build novel energy storage and conversion systems.

Selected Publications:
E. Nagelli, R. Naik, Y. Xue, Y. Gao, M. Zhang, and L. Dai “Sensor arrays from multicomponent micropatterned nanoparticles and graphene” Nanotechnology 2013, 24, 444010.
D. Yu, E. Nagelli, R. Naik, and L. Dai “Asymmetrically Functionalized Graphene for Photodependent Diode Rectifying Behavior” Angew. Chem. Int. Ed. 2011, 50, 6575.
D. Yu, E. Nagelli, F. Du, and L. Dai “Metal-Free Carbon Nanomaterials Become More Active than Metal Catalysts and Last Longer” J. Phys. Chem. Lett. 2010, 1, 2165-2173
Selected Conference Abstracts:
E. Agar, E. A. Nagelli, N. S. Sinclair, N. C. Hoyt, E. A. Striker, R. F. Savinell, J. S. Wainright. “Cost-Effective Redox Flow Batteries using a Flowable Slurry Electrode”. 2015 MRS Fall Meeting & Exhibit. November 29 – December 4, 2015, Boston, MA.
E. Agar, E. A. Nagelli, N. S. Sinclair, N. C. Hoyt, E. A. Striker, R. F. Savinell, J. S. Wainright. “Cost-Effective All-Copper Flow Battery Using Flowable Slurry Electrode for Large-Scale Energy Storage”. 228th Electrochemical Society (ECS) Meeting. October 11-16, 2015, Phoenix, AZ.
N. C. Hoyt, E. Agar, E. A. Nagelli, R. F. Savinell, J. S. Wainright, “Characterization of Carbon Black Particles for Use in Aqueous Slurry Electrodes”. 228th ECS Meeting. October 11-16, 2015, Phoenix, AZ.