Faculty Profile

Jason Ritchie
Associate Professor of Chemistry and Biochemistry
Phone Number: (662)915-5329
Email: jritchie@olemiss.edu
http://chemistry.olemiss.edu/jason-ritchie-associate-professor-of-chemistry-biochemistry/

Key Words: Ionically Conductive Polymer Electrolytes, Proton Exchange Membrane Fuel Cells, Lithium Ion Batteries, Electrolytes, PEMFC, Alternative Energy

Research Description: My group is trying to understand how the molecular structure of an ion-conducting polymer affects its observed electrochemical properties such as ionic conductivity.

We create and study new polymers that conduct Li+ and H+ cations for use as electrolytes in lithium-ion batteries and proton exchange membrane (PEM) fuel cells. We want to understand the fundamental mechanisms of H+ and Li+ transport in these materials.

We create our electrolytes by synthetically attaching an oligomeric mono-methyl polyethylene glycol (PEG) to a sol-gel polymerizable unit. The oligomeric PEG is a viscous liquid known for their ability to dissolve and conduct small cations. In addition, the PEG imparts disorder to the resulting polymer which helps the material conduct ions faster. We focus on the chemical tailoring of the properties of the electrolyte itself, in order to study the relationship between the electrolyte's structure and electrochemical properties. The first objective of our research is to elucidate the physical properties of the MePEG polymer that affect the observed electrochemical properties. In order to understand the physical properties of the MePEG polymer that lead to conductivity, we will:

  1. develop reliable methods for the measurement of the MePEG polymer's molecular weight and polydispersity index,
  2. investigate the relationship between the MePEG polymer's structure and conductivity properties, as a function of polymerization and branching,
  3. determine the dependence of conductivity on structure by artificially altering the structure of the polymer,
  4. examining thermal stability, and characterize glass transition temperatures (Tg) in these polymers to determine how segmental motions lead to Li+ transport and Grotthuss H+ transport.

The second objective of this research is to understand the mechanism of cation conductivity and small molecule diffusion in the MePEG polymer. To understand the fundamental mechanism of conductivity, we will:

  1. use isotopic and ionic substitution to determine the contribution of the Grotthuss mechanism in these electrolytes
  2. probe the vehicle mechanism of conductivity by comparing the conductivity and activation barriers with different sized vehicles
  3. correlate the viscosity of the MePEG polymer with the physical diffusion of small redox active molecules
  4. understand how the structural details of the polymer affect the susceptibility to electroosmotic drag of small redox active molecules.

Students working in my laboratory will receive a broad exposure to the fields of electrochemistry and solid-state inorganic chemistry and will become familiar with many different analytical techniques including chemical reactions under inert-atmosphere conditions using standard Schlenk techniques, solid-state synthetic reactions, and electrochemical and conductivity experiments.

Honors Theses:

Peterson, Sarah Marie (2021) A Conductivity Analysis of a Newly Synthesized Poly(Ethylene Glycol) Methyl Ether Hydroxide Electrolyte (full text)

Fox, Olivia (2021) Synthesis and Conductivity Analysis of a Methyl (Polyethylene Glycol) Comb Polymer (full text)

Heydinger, Stanton (2020) A Synthesis and Analysis of Anhydrous Hydroxide Ion Conducting Polymer Electrolytes (full text)

Groneck, Andrew (2020) Synthesis of Polyethylene Glycol - Trifluoromethyl Sulfonamide and Analysis of its Ion-Transport Properties (full text)

Ladner, Andrew (2020) The Synthesis of a MePEG-based Hydroxide Conducting Electrolyte and the Optimization of the MePEG-Tosylation Reaction (full text)

Cook, Leah Margaret (2019) Yield Stress Analysis With DV-III Rheometer (full text)

Wallace, Jeffory Taylor (2017) An Analysis of the Acid Profile of Coffee Brews: Caffeine and Chlorogenic Acid Concentrations in Different Forms of Coffee Brew. (full text)

Oliver, Meredith (2015) From Lazarus To Theophilus: How Manuscript Digitization Led To The Historical, Chemical, and Technological Understanding of Iron Gall Ink and its Counterparts. (full text)

Available Research Projects:

Anhydrous H+ Conducting Polymer Electrolytes

Project Description: Students will work in my laboratory to synthesize new H+ Conducting Polymer electrolytes from polyethylene glycol based polymers, and will use a variety of analytical and polymer chemistry measurements to understand how the structure of the polymer electrolyte effects the observed ionic conductivity.

Desired Student Qualifications: I would prefer that students have some organic chemistry laboratory experience, but am willing to take students earlier if they are highly motivated.

Project Timeline: I would typically like to have a student for 2 semesters of research.

Duties of Student Researcher: I our lab, we use both chemical synthesis techniques to make new polymers, and a variety of analytical measurements to understand polymer structure. For example, we use hydrosilylation reactions to chemically synthesize our polymers, then use techniques such as Nuclear Magnetic Resonance to verify the chemical purity of the polymers. Then we use techniques like Gel Permeation Chromotography to measure the molecular weight of the polymer, Rheometry to measure viscosity, Differential Scanning Calorimetry to understand the glass transition temperature, and AC-Impedance Spectroscopy to measure the ionic conductivity. Most students wind up doing at least some chemical synthesis and some analytical measurement.

Last Updated on 2017-12-14 16:10:38