CAS: Structure and Mechanism for Energy Capture from Anionic Seebeck Effects in Polymers

With support from the Chemical Structure, Dynamics & Mechanisms-B Program of the Chemistry Division, Professors Howard Katz of the Departments of Materials Science and Engineering and of Chemistry, and Paulette Clancy of the Department of Chemical and Biomolecular Engineering at Johns Hopkins University are developing a new type of material that can produce an electrical force when one side of the material is hotter than the other side. The electrical force comes from the rearrangement of charged atoms called ions, like the sodium and chloride of table salt. The heat energy that was used to cause this rearrangement can be recovered as more useful electrical energy. For example, this energy could be used to recharge a battery. This is a desirable way to utilize energy because the heat is often inexpensive or even free, such as from the sun or from the heat produced from applying brakes to a vehicle. The project will provide training for students at undergraduate, masters, and doctoral levels, including from the historically African-American Coppin State and Morgan State Universities, in making polymers and studying their electronic properties. Furthermore, these students will be trained in computer modeling and artificial intelligence-guided materials design. The ionic Seebeck effect in polymers, which produces a voltage from a difference in temperature, is an attractive means of harvesting electrical energy because the heat source is often free or might otherwise be wasted. It is driven by differences in the most stable arrangements of different charged species, creating an imbalance of charge in regions that differ in temperature. The chemical basis for this effect has had only limited prior analysis. The objectives of this proposal are to synthesize a rational set of cationic polymers with mobile counterions of varied size from which structure-activity relationships will be obtained governing the anionic Seebeck coefficient, and to perform experimental and computational tests of these materials to produce the necessary thermoelectric data and structural/electronic models, respectively. This study aims to derive and develop the first mechanistic explanation of the origin of Seebeck coefficients based on the redistribution of anions in media where anions are the principal mobile charge carriers, with the goal of developing more efficient conversion of heat to stored electrical energy. If successful, these studies have the potential for broad scientific impact in the areas of energy science, electrochemistry and sustainable chemistry solutions. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.