Fundamental Investigations into the Metal-Organic Framework Redox-Hopping Charge Transport

Non-technical Summary: In this project, supported through the Solid State and Materials Chemistry program in the Division of Materials Research, Professors Amanda Morris and Alan Esker of the Department of Chemistry at Virginia Polytechnic Institute and State University investigate the electronic and ionic transport properties of metal-organic frameworks. The project advances our knowledge how to control these properties and aid in developing next-generation smart windows, batteries, sensors, and catalysts. The project addresses critical, present-day energy technology challenges and, thus, holds the potential for genuinely transformative economic benefits. The research also serves as the inspiration for a permanent exhibit installation at a local children's museum for K-5 students and educational enrichment opportunities at Virginia Tech. The PIs also commit to recruiting and mentoring undergraduate and graduate students through this interdisciplinary STEM project. Technical Summary: Commercial applications for metal-organic frameworks (MOFs) have now been realized in gas sorption and catalysis, with more on the horizon in water harvesting and electrochemical applications, e.g., supercapacitors. Regarding the latter, the field has extensively studied the mechanisms of electrochemical charge transport and uncovered three primary modes: through-bond, through-space, and redox-hopping. The Morris group was among the first to propose an operative redox hopping mechanism for charge transport in MOFs. This project, supported through the Solid State and Materials Chemistry program in the Division of Materials Research, builds on this prior knowledge. The principal investigators carry out a detailed study on redox hopping-driven ion transport in MOFs using precision electrochemical investigations and modeling expertise to answer the following fundamental questions: What are the dominant pathways for ion insertion in redox hopping MOFs under non-Faradaic (migration) and Faradaic (catalytic) control? What synthetic handles can be used to manipulate ion transport in MOFs? Additionally, the research serves as the inspiration for a permanent exhibit installation at a local children's museum for K-5 students and educational enrichment opportunities at Virginia Tech and provides research opportunities to undergraduate and graduate students. 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.