EAGER: CET: Recovering Lithium During Battery Recycling Using Redox Mediators and Selective Nonaqueous Membranes

University Of Virginia Main Campus, Charlottesville VA

Investigators

Abstract

This EArly-concept Grants for Exploratory Research (EAGER) award is made in response to Dear Colleague Letter 23-109, as part of the NSF-wide Clean Energy Technology initiative. With this EAGER project the researchers pursue fundamental understanding of a clean energy technology for the extraction of lithium during recycling of lithium-ion batteries. Over the coming decade, many batteries necessary for electrification and the transition from fossil fuels to renewable energy powering our lives will reach the end of their service life. These batteries will need to be sustainably and economically recycled to extract their valuable critical materials. One critical component in batteries is lithium, and this project focuses on the selective and efficient extraction of lithium from spent lithium-ion batteries. The United States has limited domestic lithium supplies, and thus capturing lithium via battery recycling is important both to reduce the environmental impacts of mining new lithium and providing a robust supply of domestic lithium. Investigating the recycling of lithium-ion batteries has inherent benefits to society. Additionally, workforce development is a crucial outcome of this project: as part of the project undergraduate and graduate students are trained in critical mineral recovery technology. With funding from an EArly-concept Grants for Exploratory Research (EAGER) award through the NSF-wide Clean Energy Technology initiative, the principal investigators develop an understanding towards a new approach for recovery of lithium during recycling of lithium-ion battery cells. Their new method has advantages relative to more mature battery recycling technologies in that it operates at low temperature, which reduces energy input intensity and the emissions required to produce the process energy. Also, the process can be applied to selectively extract lithium, but not other cell components, allowing other more mature technology for later stage processing if desired. The process can be applied broadly to a diverse set of different electrode materials and is therefore adaptive to changes in lithium-ion chemistry with time. The net chemical inputs per battery material processed is expected to be low. The system relies on a chemical redox step where the spent battery electroactive material is oxidized using a dissolved redox shuttle within a nonaqueous electrolyte solution. This redox shuttle is then regenerated electrochemically in a cell, and the lithium is selectively transported for further downstream processing towards battery grade recycled products. The focus of this project is advancing the fundamental understanding of two critical components in the process. The first component involves chemical oxidation for lithium release from electroactive materials. Chemical oxidation experiments provide quantitative insight into how these reactions proceed in a lithium extraction process for the diverse materials used commercially in lithium-ion batteries. The expected outcomes drive broader process design and inform downstream processing inputs. The second component involves selective electrochemical recovery of lithium from nonaqueous fluid. Selective lithium recovery in an electrochemical cell requires materials that are uniquely suited to this application that are stable in the electrolyte, have high lithium conductivity, and low permeability of the redox shuttles in the system. Results from this project will inform not only this unique recycling system but also related systems such as mediated flow batteries and electrochemical recovery of critical materials from other nonaqueous waste streams. 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.