Electrolyte additive, electrolyte and lithium ion battery

Abstract

The invention discloses an electrolyte additive, an electrolyte and a lithium ion battery, and the electrolyte additive comprises 2-(2, 2-dicyanovinyl)-4-vinyl-1, 3-dioxolane and barbituric acid. Theelectrolyte additive can be applied to a battery electrolyte, a stable passivation film can be formed on a positive electrode and a negative electrode, the toughness of the passivation film is excellent, the positive electrode and the negative electrode can cover active sites without being damaged under a long-time high-temperature condition, and the floating charge performance and the overchargeperformance of a battery are improved.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to an electrolyte additive, an electrolyte and a lithium ion battery. Background technique [0002] Lithium-ion batteries are widely used in consumer electronics products and energy storage and power batteries due to their advantages such as high energy, long cycle life, and small self-discharge. With the wide application of lithium-ion batteries, its temperature adaptability and safety performance have become an important indicator of lithium-ion batteries. The stability of lithium-ion batteries is affected by many factors. Among them, the electrolyte, as an important part of lithium-ion batteries, has a major impact on its environmental adaptability and safety performance. [0003] The electrolyte is generally composed of carbonate solvents with low flash point, lithium hexafluorophosphate lithium salt and other additives. Because the solvent components are flammable and explos...

AI Technical Summary

Problems solved by technology

[0003] The electrolyte is generally composed of carbonate solvents with low flash point, lithium hexafluorophosphate lithium salt and other additives. Because the solvent components are flammable and explosive, when the battery is overcharged, overdischarged or under some extreme conditions, it is easy to Potential safety hazards, fires or even explosions

When the lithium-ion battery is overcharged, because the battery voltage rises rapidly with the increase of polarization, it will cause irreversible changes in the structure of the positive electrode active material and the oxidative decomposition of the electrolyte, which will generate a large amount of gas and release a large amount of heat, resulting in the internal discharge of the battery. The pressure and temperature rise sharply, and there are unsafe hazards such as explosion and combustion.

In addition, the existing lithium-ion batteries generally have the problem of poor float cycle performance at high temperatures.

Images