What are the Carbonate Solvents for Lithium-ion Electrolyte

What are the Carbonate Solvents for Lithium-ion Electrolyte

A carbonate solvent is a common choice for lithium-ion electrolytes, including both cyclic carbonates and linear carbonates. It has good electrical stability and a high dielectric constant. Specifically:

Cyclic carbonate solvents:

• Common types: Mainly includes Ethylene Carbonate (EC) and Propylene Carbonate (PC).

• Characteristics: EC has a high dielectric constant, strong chemical stability and low melting point, which is especially suitable for enhancing the performance of electrolyte under low temperature conditions.

• Application Scenario: Lithium battery manufacturers often use EC as a base solvent, especially for applications that require good low-temperature performance, such as electric vehicles.

Linear carbonate solvents:

• Common types: These include Dimethyl Carbonate (DMC), Diethyl Carbonate (DEC) and Ethyl Methyl Carbonate (EMC).

• Properties: These solvents are typically lower cost, with DMC standing out due to its wide range of downstream applications.

• Application scenarios: In ternary lithium batteries, the content of EMC is higher; while in lithium iron phosphate batteries, the proportion of DMC is larger.

Combined use:

• Complementing each other's strengths: By using a mix of cyclic and linear carbonate solvents, it is possible to optimize the electrolyte's performance indicators, such as increasing electrical flow and adjusting the operating temperature range.

• Customized requirements: Different battery technologies and applications may have different requirements for electrolytes, which can be better met by carefully blending the proportions of carbonate solvents.

Solvent	Structure	MW	Melting Point	Boiling Point	Flash Point	Viscosity
Ethylene Carbonate (EC)		88	37	243	160	1.93
Propylene Carbonate (PC)		102	-55	240	132	2.53
Dimethyl Carbonate (DMC)		90	4.6	91	17	0.59
Diethyl Carbonate (DEC)		118	-13	126	33	0.75
Ethyl Methyl Carbonate (EMC)		104	-14	107	27	0.65

In conclusion, carbonate solvents, as an important part of electrolyte, its diverse characteristics and flexible proportioning make it a key element in enhancing the performance of lithium batteries.