Graphite is currently used as the anode component in most rechargeable lithium-ion batteries. Replacing graphite with lithium metal holds the promise to improve the battery capacity by several times while also reducing costs. During battery charging and discharging, the lithium metal surface is prone to losing its smooth morphology and forms many sharp protrusions, a phenomenon, known as dendrite growth. Dendrite growth results in inferior battery life and induces severe safety concerns, both of which are major barriers to the commercialization of lithium-metal-based rechargeable batteries. This project aims to provide fundamental knowledge to guide the advanced manufacturing of lithium metal anodes with long cycle life and stability. It will focus on understanding the role of residual stress that accumulates within lithium metal during battery cycling in triggering lithium dendrite growth, and how its adverse effect can be eliminated by the design of a novel porous anode architecture. Integrated characterization, modeling and manufacturing activities will be carried out to achieve this goal. In addition to having major impacts on the development of next-generation batteries for electrical vehicles and electric grids, the mechanistic understanding acquired in the project will also facilitate the use of other earth-abundant metallic materials in energy storage devices. The integrated education and outreach component of the project will benefit a broad range of groups by providing authentic research experiences to native Americans and community college students, promoting undergraduate research and graduate education through active student recruitment and retention, and integrating the latest progress in battery research into curriculum on mechanics and materials science.
Despite extensive efforts, a complete understanding of the lithium dendrite growth mechanism has not yet been established. This project builds on the PIs' recent findings and will investigate stress as a key processing condition for controlling lithium surface morphology during electroplating, which has previously received little attention. It will combine in-situ and ex-situ characterizations, modeling and fabrication studies to: 1) understand how the stress, current density and plating time collectively control the lithium morphology; 2) construct a lithium morphology diagram to predict lithium plating morphology as a function of controllable processing conditions, 3) apply the acquired knowledge to design lithium anode architecture that enables stable cycling under high current densities, and 4) explore a potential cost-competitive method to manufacture high-performance lithium anodes. This research is expected to provide essential scientific guidance for the manufacturing of stable lithium metal anode structures for high capacity rechargeable batteries.
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.
