Investigation of the effect of dimethyl methylphosphonate (DMMP) on flame extinction limit of lithium-ion battery electrolyte solvents

An experimental and numerical study was conducted to quantify the flame retardant effects of different DMMP addition loadings on the flame extinction limits of four lithium-ion battery electrolyte solvents. The minimum extinguishing concentration (MEC) of CO2, which was measured using the cup-burner method, was applied to characterize the flame retardant effects of different DMMP loadings. Then, a model based on the perfectly stirred reactor concept was constructed to calculate the MEC and interpret the measurements established in the cup-burner test. A comparison was conducted between the measured and calculated MECs of N-2 and a satisfactory agreement was obtained. Further investigation found that DMMP could significantly improve the extinction temperature by clearing the H radical, suppressing the reaction temperature and increasing the sensitivity of temperature to reaction rate constants, which caused the decrease in the flame extinction limit of solvents. The experimental results showed that DMMP has a certain saturation effect on reducing the flame extinction limits of solvents. For the four solvents, the sensibilities of the flame extinction limits to the DMMP additions were different, which were ranked in the order of diethyl carbonate > ethyl methyl carbonate > dimethyl carbonate > ethyl acetate.