Global fossil fuel dependence and rising greenhouse gas emissions have led to increasing attention on energy alternatives for electricity production and personal transportation. However, deploying low-carbon energy solutions depends on parallel development of battery technologies used to power electric vehicles and store intermittent renewable energy. As lithium-ion batteries are increasingly adopted for these applications, new sustainability challenges emerge: rapid material consumption and generation of a waste stream with unknown composition and impacts. "Lessons learned" from other systems - like electronic waste - illustrate that insufficient planning for complex waste flows can result in severe environmental, social, and economic consequences.  A proactive approach is required to prevent environmental impacts from battery disposal and create pathways to recover the energy and materials these batteries contain.

This project created the first comprehensive forecast of lithium-ion batteries expected to enter the domestic waste stream as a result of electric vehicle adoption in the U.S. This waste stream was determined to contain a wide array of both high- and low-value components and materials, many of which lack an established recycling infrastructure. We determined that material commodity values are a major factor in recycling economics. Battery manufacturers are driving continued innovation towards low cost cathode and anode materials, but shifting away from high-value metals like cobalt results in reduced economic incentives for battery recyclers. As a result, policy and market interventions are required to incentivize closed-loop systems. 

The waste forecasting model we created was also used to determine that a significant fraction of used batteries retain much of their original energy storage capacity. While no longer suitable for electric vehicle use, these batteries show promise for second-life applications, such as renewable energy storage, back-up power, and electric grid load management. We investigated the technical and sustainability dimensions of a circular economy model for battery management from a life cycle basis. Findings demonstrated that second-life battery applications can provide the greatest economic and environmental benefits by extending battery lifespan and avoiding the production and use of less-efficient battery storage options. Battery reuse can also provide social benefits, particularly if it facilitates adoption of distributed renewable energy systems or creates back-up power for critical infrastructure. 

The project also investigated the sustainability issues surrounding materials contained within lithium-ion batteries. The high energy and power density of these batteries is enabled by potentially scarce resources including lithium, cobalt, nickel, manganese, and graphite. Our research showed that recycling offers a clear pathway to recover these materials for a domestic market and decrease demand for resource-intense mining activities that often take place in socially- and politically-vulnerable regions. However, research findings emphasized that realizing the potential of recycling will require new technologies, policies, designs, business models, and methods for safe transportation and handling. 

Another strategy for reducing sustainability risks is material substitution, by, for example, using engineered nanomaterials in battery anodes and cathods to provide enhanced functionality but lower mineral demands. We studied the life cycle tradeoffs of alternate battery materials and found that they lead to lower environmental impacts when their manufacturing is well-managed and their use results in a significant energy storage or lifespan advantage. However, if nano-scale manufacturing leads to increased air and water emissions, particularly to vulnerable ecosystems, these materials may create unintended freshwater pollution and ecological impacts. Results underscore the importance of applying a life cycle perspective when evaluating emerging technologies.

This life cycle perspective is also important in educating broad audiences about the tradeoffs of new technologies. This project combined research and education to engage a wide audience and share findings about lithium-ion battery sustainability.  Project funding supported training and professional development for 6 female PhD and MS and 2 female undergraduate researchers. Research was also integrated into educational outreach aimed at increasing understanding of and interest in engineering education and careers. Hands-on activities, demonstrations, and educational programs were created and delivered to over 80 female K-12 students per year during Women in Engineering at RIT summer camps. Educational assessment found that participants gained understanding and appreciation of lithium-ion batteries as part of sustainable energy solutions and of engineering as a dynamic and socially-relevant career. 

Project findings were also shared to a broader scientific and public audience. Research resulted in 16 peer-reviewed journal articles, four theses and dissertations, two unique data sets published in public repositories, and over 30 presentations to academic, public, and government audiences. Findings have been disseminated to the public via the One Universe at a Time podcast and demonstrations at the annual Imagine RIT Innovation and Creativity Festival.  

Last Modified: 10/28/2020
Modified by: Callie W Babbitt