Lithium-ion battery

A lithium-ion battery comprising:

• a positive electrode comprising a positive electrode active material;
• and an electrolyte,
• wherein the positive electrode active material comprises a lithium cobalt oxide comprising magnesium, fluorine, nickel, and aluminum,
• wherein the electrolyte comprises fluoroethylene carbonate and methyl trifluoropropionate, and
• wherein a volume ratio of the fluoroethylene carbonate to the methyl trifluoropropionate is x:100−x when a total content of the fluoroethylene carbonate and the methyl trifluoropropionate is 100 vol % and the x is greater than or equal to 5 and less than or equal to 30.

A lithium-ion battery comprising;

• a positive electrode comprising a positive electrode active material comprising a lithium cobalt oxide comprising magnesium, fluorine, nickel, and aluminum;
• and an electrolyte,
• wherein the electrolyte comprises fluoroethylene carbonate and methyl trifluoropropionate,
• wherein a volume ratio of the fluoroethylene carbonate to the methyl trifluoropropionate is x:100−x when a total content of the fluoroethylene carbonate and the methyl trifluoropropionate is 100 vol % and the x is greater than or equal to 5 and less than or equal to 30,
• wherein a discharge capacity value obtained by preparing a half cell comprising the positive electrode, the electrolyte, and a counter electrode comprising lithium metal, placing the half cell at an ambient temperature of 25° C., performing constant current charging at a rate of 0.1 C until a voltage of 4.6 V, performing constant voltage charging at 4.6 V until a current value of 0.05 C, placing the half cell at an ambient temperature of −40° C., and performing constant current discharging at the rate of 0.1 C until a voltage of 2.5 V is greater than or equal to 50% of a discharge capacity value obtained by placing the half cell at the ambient temperature of 25° C., performing the constant current charging at the rate of 0.1 C until the voltage of 4.6 V, performing the constant voltage charging at 4.6 V until the current value of 0.05 C, and performing the constant current discharging at the rate of 0.1 C until the voltage of 2.5 V, and
• wherein 1 C is equal to 200 mA/g.

A lithium-ion battery comprising:

• a positive electrode active material comprising nickel, cobalt, and manganese;
• and an electrolyte comprising a fluorinated cyclic carbonate and a fluorinated chain carbonate,
• wherein a discharge capacity value obtained by placing a half cell comprising a positive electrode comprising the positive electrode active material, the electrolyte, and a counter electrode comprising lithium metal at an ambient temperature of 25° C., performing constant current charging at a rate of 0.1 C until a voltage of 4.5 V, performing constant voltage charging at 4.5 V until a current value of 0.05 C, placing the half cell at an ambient temperature of −40° C., and performing constant current discharging at the rate of 0.1 C until a voltage of 2.5 V satisfies greater than or equal to 50% of a discharge capacity value obtained by placing the half cell at the ambient temperature of 25° C., performing the constant current charging at the rate of 0.1 C until the voltage of 4.5 V, performing the constant voltage charging at 4.5 V until the current value of 0.05 C, and performing the constant current discharging at the rate of 0.1 C until the voltage of 2.5 V, and
• wherein 1 C is equal to 200 mA/g.

A lithium-ion battery comprising:

• a positive electrode active material comprising nickel, cobalt, and manganese;
• and an electrolyte,
• wherein the electrolyte comprises fluoroethylene carbonate and methyl trifluoropropionate,
• wherein a volume ratio of the fluoroethylene carbonate to the methyl trifluoropropionate is x:100−x when a total content of the fluoroethylene carbonate and the methyl trifluoropropionate is 100 vol % and the x is greater than or equal to 5 and less than or equal to 30,
• wherein a discharge capacity value obtained by placing a half cell comprising a positive electrode comprising the positive electrode active material, the electrolyte, and a counter electrode comprising lithium metal at an ambient temperature of 25° C., performing constant current charging at a rate of 0.1 C until a voltage of 4.5 V, performing constant voltage charging at 4.5 V until a current value of 0.05 C, placing the half cell at an ambient temperature of −40° C., and performing constant current discharging at the rate of 0.1 C until a voltage of 2.5 V satisfies greater than or equal to 50% of a discharge capacity value obtained by placing the half cell at the ambient temperature of 25° C., performing the constant current charging at the rate of 0.1 C until the voltage of 4.5 V, performing the constant voltage charging at 4.5 V until the current value of 0.05 C, and performing the constant current discharging at the rate of 0.1 C until the voltage of 2.5 V, and
• wherein 1 C is equal to 200 mA/g.