PFI-TT: Development of Lithium Metal Battery with Enhanced Reliability

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

The broader impact/commercial potential of this Partnerships for Innovation - Technology Translation (PFI-TT) project is to improve the reliability of lithium metal batteries for electric vehicles and other energy storage applications. It is necessary to reduce battery pack cost-per-kWh from about $150/kWh in 2020-21 to under $100/kWh ($65-70/kWh for mainstream adoption in the US) to make electric vehicle manufacturing cost lower than that for internal combustion engine-based vehicles. Current lithium ion batteries are reaching their limit of energy density. As a result, next generation batteries must take advantage of new materials. Among the various choices, lithium metal provides the highest theoretical capacity and with a potential capacity of ~2x energy density at the cell level and ~2x lower cost compared to current lithium ion batteries. The global electric vehicle battery market is estimated to grow to about $100 billion in 2025. In addition, the energy storage services market is also expected to start growing rapidly during the next 5 years and beyond. This project improves lithium metal batteries. The proposed project focuses on demonstrating lithium metal batteries using a thin film or a coating as a modulation layer on the lithium metal surface to achieve a stable, reliable reaction. A lithium surface is inherently unstable, which leads unintended reactions and structures. These can lead to inner short-circuit, early battery failure and safety hazard. Irregular reactions also cause part of the lithium metal to become inactive, leading to capacity decay and thermal runaway. By adjusting the local electrochemical process through lithium flux, the coating promotes uniform lithium surface reaction. This project aims to develop a scalable solvent-free, thermally-enhanced and field-assisted approach to engineer the ionic transport properties of the coating on lithium surface. The flexible coating acts to interact with the lithium surface by regulating how lithium ions pass through it. Subsequently the project will systematically test the performance of lithium metal batteries equipped with such solvent-free engineered interfaces. The proposed technology enhances the reliability of lithium metal batteries, and paves the way for their commercialization. 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.