Ignition and fire hazards of cryogenically generated black mass from charged Li-ion batteries

Document Type

Article

Publication Date

7-10-2026

Department

Department of Chemical Engineering

Abstract

Cryogenically recycled black mass exhibits significant occupational and safety risks, even though cryogenic shredding itself can safely process charged Lithium-ion batteries (LIBs) without triggering fire or explosion. In this work, the fire hazards associated with cryogenically produced black mass from charged LIBs with lithium nickel‑cobalt‑aluminum oxide cathode chemistry were systematically investigated by inducing ignition with the addition of a water droplet. Combustion characteristics were monitored by thermal imaging, and key fire metrics, including flame temperature, fire duration, and flame areas, were digitally quantified. Higher state of charge (SOC) significantly increased fire severity, resulting in higher flame temperature, larger flame areas, and larger radiation energy release. At 100% SOC, approximately 200 J/g of energy was released from the onset of ignition, with peak radiation release energy reaching 400–500 W. In addition, increasing the amount of black mass further intensified fire severity. Post-ignition elemental and compositional analyses revealed evidence of carbothermal reduction, including the formation of lithium carbonate and reduced phases of cathode active materials. Through thermochemical analysis, a three-phase reaction mechanism was created to describe the phenomena present with additional thermodynamic verification. This work provides the first comprehensive assessment of fire hazards associated with the thermal runaway of black mass produced from cryogenically shredded charged spent LIBs and offers critical insights into the potential hazards encountered during post-shredding handling and downstream processing.

Publication Title

Journal of Energy Storage

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