Nick and Amber collaborated on a poster, which they presented in Chicago at the International Meeting on Lithium Batteries. They are both researchers here at the Organic Energy Storage Laboratory.
Exploiting Steric Factors in the Design of Overcharge Additives; Nicholas Mortimer, Amber J Prins, Robert Polik and Thomas F. Guarr
Lithium ion batteries are very commonly used today, but unsafe conditions can occur if expensive electronics are not used to prevent overcharging. These electronics can double the price of the battery pack, so it is important to find a more economical way to control charging. Redox shuttles are potential additives to batteries to shunt the excess current and allow the battery to be safely used to its full capacity. Numerous organic compounds have been investigated as shuttle candidates, but finding materials that possess both a sufficiently high oxidation potential and adequate durability has proven challenging. Our current approach exploits the change in molecular geometry that often accompanies the oxidation of heterocyclic compounds. By introducing bulky groups to sterically impede this reorganization, computational modeling suggests that oxidation potentials can be shifted to more positive values without sacrificing stability.
Thank you Amber and Nick, your work is appreciated.
When I found out Devinda was from Sri Lanka, I asked if he played elephant polo. He said no, but he did send us some pictures of his time back home before returning to school…
Thanks Devinda, elephants are awesome!
Brandon worked with heavy metals to synthesize large, complex structures…
The Synthesis and Metal Complexation of Bis-terpyridine Derivatives; Brandon Wackerle and Dr. Thomas Guarr
Bis-terpyridine derivatives can be used as ligands that bind with metals in solution to form complex structures. These structures can be used in many applications, including medicine, alternative energy, and molecular electronics. By deviating from the terpyridine subunit, new ways for metals to interact with the ligand can be introduced and potentially create larger, more complex structures. Iron(II) has been used to complex with the ligand and complexes between the metal and ligand have been analyzed using electrospray ionization mass spectroscopy (ESI-MS). Currently, europium is being investigated in order to compare the properties of europium and iron complexes. This will also enable us to observe how a transition metal behaves compared to an f-block element when complexed with a bis-terpyridine.
Brandon is working towards a degree in biochemistry from Grand Valley State University. He has one year left to complete his degree and his future is bright. Thanks for a great summer.
Jessica was kept busy synthesizing this summer….
Development of Heterocyclic Catholyte Molecules for Application in Redox Flow Batteries; Jessica D. Scott and Thomas F. Guarr
Accompanying the increased discussion over climate change and global warming in the news, there is a widespread desire to research and design stable and cost-effective methods to store renewable energy on a large scale. One possible answer to the energy crisis may be found in the use of redox flow batteries. Redox flow batteries have the ability to convey chemical energy, generated from electrochemically reversible reactions, into electrical energy which could then be stored for later use. Research suggests that heterocyclic derivatives can be paired with extended viologen systems to produce very desirable electrochemical properties.
Jessie graduated from Hope College this spring with an ACS Certification Chemistry degree, spent her summer with us, and is continuing on to work in the Chicago area. Best wishes for your future, Jessie!
Taylor performed research on electroactive materials for electrode surfaces this summer…
Synthesis of Bispyridine Derivatives for Chemically Modified Electrodes; Taylor Grace, Dr. Thomas Guarr
Attachment of electroactive materials to an electrode surface can result in the formation of modified electrodes suitable for applications in displays, electrocatalytic devices, or organic batteries. Pyridinium compounds are readily and reversibly reduced, and previous work has demonstrated that bispyridine species are especially stable in both their oxidized and reduced states. The objective of this project is to prepare several different bispyridinium compounds that can be electrochemically polymerized or covalently attached to an electrode surface. The resultant chemically modified electrodes will be characterized by spectroscopic and electrochemical methods.
Taylor is pursuing a degree in chemistry with a minor in biology at Western Michigan University. We loved having her energy with us this summer and we wish her all the best when she returns to WMU.
James continued our insights into alternatives to platinum as an oxygen reduction catalyst…
Investigation of Metal(II) Tetradiphenylaminophthalocyanines for Oxygen Reduction Catalysis in Fuel Cells; James A. Wortman, Thomas F. Guarr
Catalytic oxygen reduction (OR) is an important reaction in fuel cell design. Platinum has been used as an OR catalyst, but its high cost has made large-scale applications impractical. The purpose of this study was to investigate metal(II) tetra(diphenylamino)phthalocyanine (MT4(dpa)Pc) complexes as potential cheap alternatives to platinum. The obtained complexes were electropolymerized into thin films using cyclic voltammetry (CV). These polymer films may possess improved OR capabilities due to the nature of the diphenylamine substituent.
James is (another!) Chemical Engineering student from MSU. He is part of the MSU Regional champion Chem-E-Car team and will join Brian and Mark at the Chem-E-Car competition in San Francisco this November. Good luck to them and thank you to James for his hard work.
Brian helped us this summer by developing better prototypes for redox flow batteries. His designs aided understanding of the reaction inside the battery cell.
Design of a Highly Efficient and Cost Competitive Organic Redox Flow Battery; Brian Chiou, Thomas F. Guarr
Renewable energy technology is growing rapidly. However, renewable energy relies heavily on energy storage systems to balance fluctuating energy generation. The high manufacturing cost and limited life cycle of current commercial battery technology inhibits large scale grid storage application. This research project focuses on an organic flow battery with significantly lower manufacturing cost and minimal chemical degradation for longer cycle life.
Brian graduated this year with a Chemical Engineering degree from MSU. He is presently working for LG here in Holland. He is also continuing to further his research in the above subject. Thanks for your work, Brian.
Many thanks to Devinda for spending his summer with us synthesizing Bispyridine compounds.
Synthesis of Linear Bispyridines and Bispyridinium Compounds for Energy Storage Applications; Devinda Wijewardena and Dr. Thomas F. Guarr
Redox flow batteries store energy in electrolyte solutions that flow through the battery during charge and discharge cycles. They offer a very inexpensive and scalable energy storage capability that can be utilized in grid applications. Phenylene-bridged linear bispyridinium compounds possess useful electrochemical properties that could be used in redox flow batteries. Current redox flow batteries use electrolytes with compounds containing elements such as vanadium and bromine, which are both expensive and toxic. However, phenylene-bridged linear bispyridinium compounds could be synthesized organically through effective and efficient synthetic routes. One synthetic route involves a Suzuki-Miyaura Coupling using 1,4-phenylenebisboronic acid and 4-bromo-2,6-dimethylpyridine as starting materials and a palladium catalyst. Another route uses a Hantzsch pyridine synthesis and requires multiple steps. However, it is more cost-effective and environmentally friendly than the Suzuki-Miyaura coupling. The bispyridine thus synthesized via either route was then alkylated to form the bispyridinium compound and characterized using LCMS, NMR, and cyclic voltammetry.
Devinda is a Chemical Engineering student at MSU from Sri Lanka. He has returned to the other side of the earth for a visit before returning to school and we wish him another great year at MSU.
Mark joined our lab for the summer and made some important contributions to our understanding of the dynamics of the redox cell via Raman spectra.
The Novel Application of Raman Spectroscopy for Depth Profiling in Transparent Electrochromic Cells, Mark Elinski and Thomas Guarr
Electrochromic compounds exhibit intense color changes in redox reactions and have shown functionality in mirrors windows, and display devices. Several electrochromic compounds have been synthesized, dissolved in solution, and injected into transparent electrochemical cells. The objective of this project is to use Raman spectroscopy to measure the concentration of each compound in the cell as a function of cell depth. To accomplish this, a confocal Raman microscope was used to obtain Raman spectra at small depth intervals between the anode and the cathode of the cell. The reduced and oxidized forms of each material in the cell were also isolated, and their unique Raman spectra were measured. The concentrations of these reduced and oxidized molecules at each depth in the cell were modeled from these isolated spectra and the composite spectrum at each depth. This novel Raman depth profiling technique reveals that different electrochromic materials result in different concentration gradients in the cell, and surprisingly shows that even neutral compounds display a varying concentration throughout the depth of the cell. This technique can further be applied to reaction monitoring in batteries and electrocatalytic systems.
Mark is a Chemical Engineering major at Michigan State University. He also plays in the Spartan Marching Band, so we will be looking for him on the football field at half time!
Much appreciation to Hope College for hosting the Summer Symposium on July 15. Also thank you for including our interns and allowing us to present posters. It was a great day.