Thermal
runaway is one of the main causes of lithium-ion battery
failure or even explosion, accompanied by the leakage of toxic substances
into the environment. In the present work, a severe thermal-runaway
process of commercialized LiNi0.6Mn0.2Co0.2O2 and LiNi0.8Mn0.1Co0.1O2 batteries was simulated, and the biohazards
of the produced particles were discussed. Composition analysis revealed
that thermal-runaway particles contained multiple toxic metallic and
nonmetallic elements (Ni, Co, Mn, Al, Cu, S, Si, P, and F), accompanied
by valence changes of Ni, Co, and Cu. More importantly, a typical
microorganism, Escherichia coli, was
chosen as the test organism, and the biotoxicity of thermal-runaway
particles was assessed by the electrochemical method. Corresponding
pristine cathode materials were analyzed and compared simultaneously.
The results indicated that the thermal-runaway particles would cause
instant inhibitions on bacterial respiratory activities in the range
of 25–200 mg/L, and cell membrane damages were observed after
exposure to thermal-runaway particles for 5 h, whereas the corresponding
pristine cathode materials only exhibited minor effects on bacterial
activities in the same conditions. Moreover, no significant inhibitory
impacts were detected in thermal-runaway particles’ supernatants,
which excluded ion dissolution as a major factor to bacterial toxicity
in the short time period. The generation of the superoxide anion indicated
a dominant role of reactive oxygen species in the biotoxicity of thermal-runaway
particles. The present study focuses on the toxic effect of particles
from the thermal-runaway process of lithium-ion batteries, which has
significant implications for spent batteries disposal and environment
protection.