Lithium-ion battery electrolyte with high fire retardant and electrochemical properties and preparation method thereof

Abstract

The invention discloses lithium-ion battery electrolyte with high fire retardant and electrochemical properties and a preparation method thereof. The lithium-ion battery electrolyte contains a solvent, lithium salt, a fire retardant and additives. The preparation method comprises the following steps: S1, dissolving the lithium salt into an organic solvent to obtain electrolyte with the concentration of 0.8-1.2mol / L; and S2, adding the fire retardant and additives to obtain fire retardant electrolyte, wherein the mass percentage content of the fire retardant accounts for 10-50% of the total mass of the fire retardant electrolyte, and the usage amount of the additive accounts for 1-10% of the total mass of the electrolyte. The lithium-ion battery electrolyte with high fire retardant and electrochemical properties has the advantages that the additive is added in the electrolyte for a lithium ion battery, and meanwhile, an additive or an additive composition which can prevent the fire retardant from degrading electrochemical properties of the electrolyte is added, so that the electrolyte has fire retardant property or noninflammability, and the security of the battery is improved; meanwhile, the influence on the electrochemical properties of the battery caused by the fire retardant is overcome, so that the properties of the battery are excellent.

Description

technical field [0001] The invention relates to the technical field of battery electrolyte, in particular to a lithium-ion battery electrolyte with high flame retardancy and electrochemical performance and a preparation method thereof. Background technique [0002] Due to the advantages of high energy density, high output voltage, long cycle life, and low environmental pollution, lithium-ion batteries have extremely important applications in the fields of electronic products, electric vehicles, aerospace, and energy storage. However, in recent years, there have been frequent reports of fires and even explosions caused by lithium-ion batteries, and the safety of lithium-ion batteries has attracted widespread attention. At the same time, safety issues are also a bottleneck restricting the development of lithium-ion batteries in the direction of large-scale and high-energy. [0003] The most important components of a lithium-ion battery are the positive and negative electrode m...

AI Technical Summary

Problems solved by technology

The current lithium-ion battery electrolyte mainly uses carbonate organic compounds as solvents. These solvents have a very low flash point, which makes the electrolyte extremely flammable. When the battery is in a harsh environment or abused, it is easy to cause thermal runaway and cause an explosion.

[0004] Chinese patent document CN102002205A, "Flame-retardant and heat-resistant materials for battery tanks and its preparation method", discloses a halogen-containing flame-retardant ABS, which greatly limits its application in the field of lithium batteries due to the inability to use ultrasonic heat-sealing technology

Since both chlorine and bromine are strong oxidants, they will cause safety hazards when they coexist with organic solvents in the electrolyte; in addition, graphite after lithium intercalation is a strong reducing agent, and it will undergo rapid redox reactions with chlorine and bromine. The negative electrode shows the formation of electrochemically inert lithium chloride or lithium bromide, which interferes with the formation of SEI, further affects cycle performance and increases interfacial impedance

Therefore, there are insurmountable technical problems in halogen-containing flame retardant technology.