Date of Award
2026
Document Type
Open Access Dissertation
Degree Name
Doctor of Philosophy in Chemical Engineering (PhD)
Administrative Home Department
Department of Chemical Engineering
Advisor 1
Lei Pan
Committee Member 1
Timothy Eisele
Committee Member 2
Michael Mullins
Committee Member 3
Kazuya Tajiri
Abstract
Recycling of lithium‑ion batteries is expanding rapidly, yet the hazards associated with processing charged cells remain insufficiently characterized. A central assumption challenged in this work is the belief that mechanically shredded charged cells produce black mass that is inherently safe compared to the materials in a cell level. Industrial practice often treats post‑shredding material as chemically inert, overlooking how battery chemistry, state of charge (SOC), contamination, and processing conditions govern reactivity, thermal‑runaway initiation, and airborne emission behavior. Across these chapters, this dissertation demonstrates the inherent risk and storage‑related hazards of charged black mass. Collectively, the findings establish a unified mechanistic understanding of charged‑cell processing hazards and provide a safety architecture to support the design of safer, scalable recycling systems.
The research begins with a literature review of pretreatment strategies, comminution methods, and black‑mass properties as they relate to process safety. Experimental chapters show that cryogenically processed black mass can undergo thermal runaway, reveal how cathode composition, SOC, electrolyte retention control reactivity, and quantify how metallic contaminants fundamentally alter thermal‑runaway pathways. Additional studies provide the first systematic characterization of particulate emissions during black‑mass thermal runaway that which would be seen in recycling incidents, demonstrating that toxic, cathode‑derived metal oxides dominate the resulting aerosols. Long‑term storage experiments show that charged black mass held under argon undergoes slow, spontaneous cathode lithiation rather than thermal runaway, revealing a previously unrecognized stabilization pathway while confirming that significant reactivity hazards can persist for weeks.
Finally, a pilot‑scale evaluation of an integrated dry‑mechanical preprocessing system demonstrates that finer grate sizes and a dedicated multipass liberation loop markedly safely yield high recovery of black mass. The system’s modular enclosure, staged ventilation, and dust/VOC‑capture architecture enable stable, modular, and efficient continuous processing of cells. Overall, this research provides frameworks to improve lithium-ion battery recycling safety.
Recommended Citation
Szczap, John Louis, "MECHANISTIC FOUNDATIONS AND SAFETY ASSESSMENT OF DRY-MECHANICAL RECYCLING OF CHARGED LITHIUM-ION BATTERIES", Open Access Dissertation, Michigan Technological University, 2026.