SBIR Phase II: Metal Foils for High Energy Density, Low-cost, Lithium-ion Batteries

The broader/commercial impact of this Small Business Innovation Research (SBIR) Phase II project is the development of base-metal alloy foils as a cost-effective, lightweight replacement for copper current collectors in lithium-ion batteries (LIBs). Copper is currently the third most expensive and third heaviest component in LIBs, costing battery manufacturers over $7 billion annually. By replacing copper with these innovative foils, the project targets a long-term material cost reduction of over 50%, saving more than $3 per kilowatt-hour (kWh) and improving gravimetric energy density by over 5%. With LIB pack prices at approximately $107/kWh and batteries accounting for 40% of electric vehicle (EV) production costs, this innovation supports the national goal of reducing battery prices to $50–$75/kWh to achieve cost parity with internal combustion engine vehicles. Additionally, the project addresses critical supply chain vulnerabilities by offering a domestically produced alternative to copper foil, which is almost exclusively manufactured in Asia. By supporting domestic manufacturing, this project helps strengthen the U.S. battery supply chain, promote job creation, and reduce reliance on critical materials facing projected shortages, such as copper, while enabling global competitiveness for U.S.-based energy technology solutions. The intellectual merit of this project lies in the novel development and application of base-metal alloys that are electrochemically stable against lithium, enabling their use as current collectors on the anode side of LIBs—a role previously thought incompatible with most base-metal-based materials like aluminum due to lithium alloying. Preliminary research discovered that certain base-metal alloys demonstrate suppressed lithium reactivity in standard battery electrolytes, a counterintuitive result given the known lithium-alloying behavior of the individual metal components. The research objectives include characterizing the passivation mechanisms that provide this electrochemical stability, optimizing alloy compositions and surface treatments, and ensuring compatibility with commercial battery manufacturing processes. This will involve detailed studies using surface analysis (e.g., XPS, ToF-SIMS), electrochemical testing (e.g., half- and full-cell cycling, impedance spectroscopy), and mechanical and corrosion assessments. The anticipated outcomes include a scalable, weldable, and conductive foil that performs comparably to copper in commercial-format multi-layer pouch cells, validated through third-party testing and sample evaluations with customers. This work advances the fundamental understanding of alloy-electrolyte interactions and enables a transformative material for next-generation energy storage. 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.