SEP: Non-Aqueous Redox Flow Battery Chemistries for Sustainable Energy
Electricity accounts for ~40% the energy consumed in the U.S. and most is derived from non-renewable resources including fossil and nuclear fuels. Pathways to greater energy sustainability will require the use of renewable resources including solar and wind. The lack of reliable, low-cost energy storage is one of the key challenges to large-scale integration of renewables, with their intermittency, into the grid. With further reductions in cost and increases in energy and power densities, redox flow batteries (RFBs) are poised to play an important role in providing sustainable energy storage solutions. RFBs based on aqueous chemistries generally fall short of cost targets for large-scale implementation. The use of non-aqueous instead of aqueous chemistries is expected to yield RFBs with much lower costs (assuming solvent recycle) and higher energy densities due to their higher operating voltages (energy is proportional to operating voltage).
The proposed project will deliver the transformative scientific and engineering outcomes needed to demonstrate cost-competitive, non-aqueous RFBs for grid storage applications. The research will focus on the use of first row metal B-diketonates, an attractive class of complexes because of their flexibility with regard to composition, electrochemical properties, and ease of synthesis from low cost and green chemicals. The research has three objectives. Understanding the redox chemistry of metal B-diketonate complexes will be advanced through the development of detailed structure-composition-function relationships. The most promising chemistries identified from these relationships will be characterized at engineered electrodes to define the kinetics and mechanisms as they relate to RFB applications, and the results will be used to design and fabricate small-scale flow cells to evaluate large-scale RFB relevant performance characteristics. Finally, an integrated sustainable design and assessment framework will be used to guide the research and evaluate sustainability performance across the electrochemistry, device, and grid integration levels. The results will be compared to those for other storage technologies (e.g. pumped hydro).
This proposed project will establish a new sustainable energy pathway for advancing fundamental battery chemistries to large-scale RFBs for utility scale storage applications. The introduction of sustainable energy storage technologies into the grid could lead to significant reductions in non-renewable energy consumption and greenhouse gas emissions.
Three graduate students and a post-doctoral scholar will be trained as part of an interdisciplinary team working on technology that could transform the electricity grid. On graduation, they will be well prepared for leadership positions in industry, government, or academia. To ensure broadest impact, results from the research will be disseminated via participation of project personnel in conferences and publications in scholarly journals. In addition, the PI and co-PI will integrate selected research results into their courses including a first year engineering course.
The Education and Workforce Development Plan will enhance diversity and integrate research and education using layered research teams and teacher training. The layered research teams will engage underrepresented minority students attending high schools bordering the University of Michigan (UM) and Case Western Reserve University (CWRU), undergraduate students participating in the NSF funded Michigan Louis Stokes Alliance for Minority Participation and REU programs, and graduate students and post-doctoral scholars at the UM and CWRU in research and on-campus workshops and enrichment programs. This type of engagement has been particularly effective at increasing the number of underrepresented minority high school students enrolling in STEM as well as providing undergraduate and graduate students and post-doctoral scholars with valuable mentoring and teaching opportunities. Finally, the teacher training program will provide up to 15 teachers from under-resourced districts and/or districts with high underrepresented populations with three days of training on concepts of electrochemical energy storage, and life cycle analysis.