The goal of this CAREER project is to build an interdisciplinary materials research and educational program by developing a novel class of polymer electrolyte materials that will be useful for fuel cell applications. Although proton exchange membrane fuel cells (PEMFCs) are touted as efficient, reliable, and environmentally friendly energy sources, broad use of this promising technology has been limited by insufficient development of polymer electrolyte materials that can overcome the shortcomings of Nafion, the current state-of-the-art proton exchange membrane (PEM). To prepare new PEM materials that can outperform Nafion in fuel cell operation, Professor Chulsung Bae of the Department of Chemistry at University of Nevada Las Vegas will (a) develop a new synthetic strategy of PEMs that take advantages of both partially fluorinated ionomers and aromatic main-chain polymers, and (b) carry out a systematic study of the relationship between polymer structure and membrane properties. This approach will generate a sulfonic acid group that is much stronger than the aryl sulfonic acid typically found in currently available aromatic polymer ionomers, and create PEMs of a diverse range of structures that can allow better understanding of the molecular-level structure property relationships. Due to the multidisciplinary nature of fuel cell research program, students working under this CAREER project will be exposed to interactions with experts in synthetic chemistry, materials characterization, and engineering and thus be given an appreciation of the multiple aspects of a major research undertaking and the many potential paths available for graduate research and future careers.
NON-TECHNICAL SUMMARY Fuel cells, which convert the chemical energies stored in fuel directly into electrical energy, are expected to be a key technology for meeting energy needs in the twenty-first century. The goal of this CAREER project is to combine different fields of chemistry and materials science/engineering and create novel materials that will provide molecular-level insight into material property and play a key role in the development of commercially viable fuel cell technologies globally. Owing to the exciting and multidisciplinary nature of fuel cell research, this CAREER project will attract participants from a wide range of areas, contribute to the infrastructure and programmatic basis for research and education opportunitiese.g., graduate student training, graduate mentoring of undergraduate research assistants, classroom demonstrationsand create an academic/private industry partnership as a possible career path for students. In addition to basic research and education programs for students, building a bridge between the PI's fuel cell research and the general public's increasing concern about global climate change and gradual desire for clean alternative energy production will enhance scientific literacy, broadening the impact of this research on the society.
Chulsung Bae at Rensselaer Polytechnic Institute (RPI) received an NSF Grant titled "CAREER: Development of Novel Polymter Electrolytes-Synthesis and Applicaitons in Fuel Cells" (DMR 1261331). The intellectual merit of this project is to develop novel proton-conducting polymer electrolytes by integrating various fields of chemistry and material characterization. With the support of the NSF CAREER grant, Bae's research group developed a mild polymer functionalization method using iridium-catalyzed borylation of aromatic C-H bonds and subsequent palladium-catalyzed Suzuki cross-couplings with various functionalized aryl bromides. Recent examples of the polymer funcitonalization include the incorporation of various sulfonate moieties to aromatic polymers (Fig. 1a). The group also discovered that the proton transport properties of proton exchange membrane (PEM) fuel cells depend not only on polymer morphology but also on the acidity of sulfonated polymers. As shown in Fig. 1, polymer membranes with strongly acidic pendant chains (i.e., -CF2SO3H) achieve proton conductivity that is much higher than that of less acidic sulfonated polymers at low relative humidity, even though they all have similar morphology structures. The broad impact of the CAREER grant includes (i) the development of partially fluorinated superacidic polymers, which are currently being tested in collaborators' laboratories (academic, industrial, and DOE national labs) for a variety of energy conversion devices, (ii) the training of undergraduate and graduate students, and (iii) education about the important of clean energy technology via demonstrations in class settings and through public outreach activities (e.g., publich speeches on sustainable energy issue at the American Chemical Society National Meeting). A high school intern involved in this project received first place in a regional science fair and is currently pursuing a doctoral degree in chemistry.
