EAGER: Suppressing Lithium Dendrite Growth by Functionally Graded Materials

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Current lithium-ion batteries use a mixture of active materials, conductive additives, and binders, which have been quickly reaching the limit of their functionality in terms of energy density, power efficiency, and durability. This EArly-concept Grant for Exploratory Research (EAGER) project addresses developing a fundamental scientific understanding of a new manufacturing process as well as addressing the bottleneck in the development of the next generation of rechargeable batteries. The technology can also be applied to the fabrication of other newly designed materials, such as free-standing and binder-free composites. The broader impacts are potentially very large, and the approach could be transformative, as the approach has direct application in the automotive, electronics, agricultural equipment, aerospace, and defense industries. As such, the project directly impacts economic welfare and national security of the United States. In addition to supporting graduate students, the project will bring education opportunities for learning state-of-the-art fabrication processes to a diverse array of students, including women, the disabled, and underrepresented minorities in science, technology, engineering, and math (STEM). Social events like the annual Maker Faire at Kansas City (a two-day exhibit and science show, that drew more than 17,000 visitors ranging in age from toddlers to grandparents from nearly all 50 states in 2017) will be utilized to disseminate and share the research findings, as well as bring education to the general public. While being the lightest metals (0.534 g/cm3) and possessing the lowest negative reduction potential (-3.05 V) against a standard hydrogen electrode, lithium metal is merited with extremely high theoretical specific capacity (3,829 mAh/g) as compared to carbon anode in lithium-ion batteries (with a specific capacity of 372 mAh/g). Although promising, the development of rechargeable lithium metal batteries has been impeded by such bottlenecks as Li dendrite growth. To address this issue, the Electric-Field-Augmented Ultrasonic Spray Pyrolysis (EFAUSP) process will enable the fabrication of functionally graded materials (FGMs), which can suppress Li dendrite growth. However, to date, there exists a knowledge gap in understanding the synergistic effects of the spray's generation, transport, and deposition in the EFAUSP process. For example, the turbulent jet with sprays possesses a series of eddies that determine the distribution of deposition droplets or particles and, eventually, deposition pattern. The research will provide comprehensive knowledge of the turbulence-spray interactions to realize the fabrication of FGMs. In addition, new knowledge and tools will be developed to examine what the best FGMs are for controlling and suppressing Li dendrite growth, which will have a significant impact on the battery industry. This potentially transformative work is a crucial step on the path to making rechargeable lithium metal batteries commercially available. Moreover, the fundamental knowledge gained in the work will allow the development of a simple, low-cost, and scalable fabrication technology that could revolutionize battery fabrication. This technology will have a significant impact on society through its effects on energy, transportation, the portable device industry, and other areas.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.