EPSCoR Research Fellows: NSF: Advancing Lithium Metal Protection with Ion-Conducting Polymer Coatings

A fully electrified transportation is desired for pursuing a green, decarbonized, and sustainable society. The current market share of electric vehicles is still low, mainly due to the insufficiencies of the state-of-the-art lithium-ion batteries (LIBs) in energy density, cost, lifetime, and safety. To possibly change the situation, lithium (Li) metal batteries (LMBs) hold a great promise, in which Li metal serves as the anode in place of graphite in LIBs.

Such switch can significantly increase the cell energy density by about 50%. Nevertheless, Li metal anode has been hindered from its practical application since 1970s, since Li metal is highly reactive to liquid organic electrolytes with the formation of the solid electrolyte interphase (SEI). The SEI layer is inhomogeneous in compositions and properties while unstable with cell cycling.

Even worse, the SEI layer is easy to cause Li dendritic growth during plating. The SEI formation leads to the consumption of both cyclable Li and liquid electrolytes with the increased cell impedance, while Li dendrites risk cell safety and accelerate the formation of SEI. Thus, they are two intertwined daunting issues and challenging to tackle.

This Research Infrastructure Improvement (RII) EPSCoR Research Fellows project will provide a fellowship to an Associate Professor and training for a graduate student at the University of Arkansas. This fellowship will be conducted in collaboration with researchers at National Renewable Energy Laboratory. To address the above issues of Li anode, the project will apply ion-conducting polymeric lithicones on the anode as surface coatings via molecular layer deposition.

The project will further utilize multiscale and cryogenic electron microscopy at NREL to achieve the following objectives: (1) Understanding chemical corrosions of Li metal; (2) Probing the structure-property evolution of the lithicone coatings with cycling; and (3) Advancing fundamental understanding of the protection mechanism of the lithicone coating. The fellowship will establish a long-term collaboration with NREL for understanding the failure mechanism of the Li anode and developing next-generation rechargeable batteries.

The research, education, and outreach opportunities derived from the fellowship project will have potential to transform the PI’s career trajectory and have tangible benefits to the home institution and jurisdiction.

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.