Lithium-ion electrolytes containing flame retardant additives for increased safety characteristics

A lithium-ion electrochemical cell comprising:

• an anode;
• a cathode;
• an electrolyte interspersed between the anode and the cathode, wherein the electrolyte comprises a mixture of:
• an ethylene carbonate (EC);
• an ethyl methyl carbonate (EMC);
• a fluorinated co-solvent selected from the group consisting 2,2,2-trifluoroethyl butyrate (TFEB), di-2,2,2-trifluoroethyl carbonate (DTFEC), 2,2,2-trifluoroethyl methyl carbonate (TFEMC), mono-fluoroethylene carbonate (FEC), ethyl trifluoroacetate (ETFA), 2,2,2-trifluoroethyl acetate (TFEA), 2,2,2-trifluoroethyl propionate (TFEP), ethyl-2,2,2-trifluoroethyl carbonate (ETFEC), propyl-2,2,2-trifluoroethyl carbonate (PTFEC), methyl-2,2,2,2′,2′,2′-hexafluoro-i-propyl carbonate (MHFPC), ethyl-2,2,2,2′,2′,2′-hexafluoro-i-propyl carbonate (EHFPC), fluoropropylene carbonate (FPC), trifluoropropylene carbonate (TFPC), methyl nonafluorobutyl ether, 2,2,3,3,3-pentafluoropropyl methyl ether, 1,1,3,3,3-pentafluoro-2-trifluoromethyl ether, 2,2,3,3-tetrafluoropropyl difluoromethyl ether, 1,1,2,3,3,3-hexafluoropropyl ethyl ether, and perfluoropolyether;
• a flame retardant additive selected from the group consisting of triphenyl phosphate (TPhPh/TPP/TPPa), tributyl phosphate (TBuPh), triethyl phosphate (TEtPh), bis(2,2,2-trifluoroethyl) methyl phosphonate (TFMPo), triphenyl phosphite, tris(2,2,2-trifluoroethyl) phosphate, tris(2,2,2-trifluoroethyl) phosphite, diethyl ethylphosphonate, and diethyl phenylphosphonate;
• and,
• a lithium salt,
• wherein the electrochemical cell operates in a temperature range of from about −50 degrees Celsius to about 60 degrees Celsius and further wherein the electrolyte comprises from about 5% to about 30% by volume flame retardant additive.

A lithium-ion electrochemical cell comprising:

• an anode;
• a cathode;
• an electrolyte interspersed between the anode and the cathode, wherein the electrolyte comprises a mixture of:
• an ethylene carbonate (EC);
• an ethyl methyl carbonate (EMC);
• a fluorinated co-solvent selected from the group consisting 2,2,2-trifluoroethyl butyrate (TFEB), di-2,2,2-trifluoroethyl carbonate (DTFEC), 2,2,2-trifluoroethyl methyl carbonate (TFEMC), mono-fluoroethylene carbonate (FEC), ethyl trifluoroacetate (ETFA), 2,2,2-trifluoroethyl acetate (TFEA), 2,2,2-trifluoroethyl propionate (TFEP), ethyl-2,2,2-trifluoroethyl carbonate (ETFEC), propyl-2,2,2-trifluoroethyl carbonate (PTFEC), methyl-2,2,2,2′,2′,2′-hexafluoro-i-propyl carbonate (MHFPC), ethyl-2,2,2,2′,2′,2′-hexafluoro-i-propyl carbonate (EHFPC), fluoropropylene carbonate (FPC), trifluoropropylene carbonate (TFPC), methyl nonafluorobutyl ether, 2,2,3,3,3-pentafluoropropyl methyl ether, 1,1,3,3,3-pentafluoro-2-trifluoromethyl ether, 2,2,3,3-tetrafluoropropyl difluoromethyl ether, 1,1,2,3,3,3-hexafluoropropyl ethyl ether, and perfluoropolyether;
• a flame retardant additive selected from the group consisting of triphenyl phosphate (TPhPh/TPP/TPPa), tributyl phosphate (TBuPh), triethyl phosphate (TEtPh), bis(2,2,2-trifluoroethyl) methyl phosphonate (TFMPo), triphenyl phosphite, tris(2,2,2-trifluoroethyl) phosphate, tris(2,2,2-trifluoroethyl) phosphite, diethyl ethylphosphonate, and diethyl phenylphosphonate;
• and,
• a lithium salt,
• wherein the electrochemical cell operates in a temperature range of from about −50 degrees Celsius to about 60 degrees Celsius and further wherein the electrolyte comprises 1.0 M LiPF6 lithium salt in 20% by volume ethylene carbonate (EC) plus 55% by volume ethyl methyl carbonate (EMC) plus 20% by volume 2,2,2-tri-fluoroethyl butyrate (TFEB) plus 5% by volume triphenyl phosphate (TPhPh/TPP/TPPa).