Currently,the effective and clean suppression of lithium-ion battery (LIB) fires remains a challenge.The present work investigates the use of various inhibitor doses (Xin) of dodecafluoro-2-methylpentan-3-one(C6F12O) in 300 Ah LIBs,and systematically examines the thermal and toxic hazards of the extinguished batteries via real scale combustion and gas analysis.The inhibitor is shown to be completely effective.The inhibition mechanism involves a combination of chemical inhibition and physical cooling.While the chemical inhibition effect tends to saturate with increasing Xin,the physical cooling remains effective at higher inhibitor doses.However,extinguishing the battery fire with a high Xin of C6F12O is found to incur serious toxicity problems.These results are expected to provide a guideline for the design of inhi-bitor doses for the suppression of LIB fires.