Where Can Aluminum Go When Batteries Die?

Battery‐derived aluminum is transformed from contaminated waste into an alloying resource for high‐performance Fe‐based alloys. Through controlled Al content and processing, dual‐phase austenite/ferrite microstructures with TRIP‐like behavior are achieved. Atomic‐scale analysis reveals B2 nanoprecipitation and impurity segregation effects, linking nanoscale features to macroscopic mechanical performance. Abstract By 2030, the European Union (EU) is expected to have over 30 million electric vehicles (EVs), making the environmental challenges of end‐of‐life batteries a significant concern. While repurposing extends battery use in less demanding applications, recycling reclaims materials for new products, conserves metal resources, and lessens environmental impact. However, most recycling follows a “shred‐first, sort‐later” approach, which mixes components and makes separation difficult, leading to contamination of recovered materials and reducing their quality and performance. Aluminum (Al), the cathode current collector, is particularly affected by this issue, as impurities build up and have limited solubility, preventing direct reuse in new batteries. In this work, an alternative recycling method is introduced where battery‐derived Al is used as a key alloying element in Fe‐based alloys, fully neutralizing impurity effects. By controlling Al levels and applying thermomechanical processing, typical austenite/ferrite microstructures can be formed with mechanical properties comparable to dual‐phase (DP) and transformation‐induced plasticity (TRIP) steels. Nanoscale characterization shows localized B2 nanoprecipitates in ferrite and impurity segregation at grain and phase boundaries, both influencing fracture behavior. These results demonstrate a scalable and sustainable approach to transforming contaminated battery scrap into a high‐value resource for advanced alloy development. Battery-derived aluminum is transformed from contaminated waste into an alloying resource for high-performance Fe-based alloys. Through controlled Al content and processing, dual-phase austenite/ferrite microstructures with TRIP-like behavior are achieved. Atomic-scale analysis reveals B2 nanoprecipitation and impurity segregation effects, linking nanoscale features to macroscopic mechanical performance. Abstract By 2030, the European Union (EU) is expected to have over 30 million electric vehicles (EVs), making the environmental challenges of end-of-life batteries a significant concern. While repurposing extends battery use in less demanding applications, recycling reclaims materials for new products, conserves metal resources, and lessens environmental impact. However, most recycling follows a “shred-first, sort-later” approach, which mixes components and makes separation difficult, leading to contamination of recovered materials and reducing their quality and performance. Aluminum (Al), the cathode current collector, is particularly affected by this issue, as impurities build up and have limited solubility, preventing direct reuse in new batteries. In this work, an alternative recycling method is introduced where battery-derived Al is used as a key alloying element in Fe-based alloys, fully neutralizing impurity effects. By controlling Al levels and applying thermomechanical processing, typical austenite/ferrite microstructures can be formed with mechanical properties comparable to dual-phase (DP) and transformation-induced plasticity (TRIP) steels. Nanoscale characterization shows localized B2 nanoprecipitates in ferrite and impurity segregation at grain and phase boundaries, both influencing fracture behavior. These results demonstrate a scalable and sustainable approach to transforming contaminated battery scrap into a high-value resource for advanced alloy development. Advanced Science, EarlyView.