A kind of high-voltage lithium cobalt oxide lithium ion battery non-aqueous electrolyte and lithium ion battery

Abstract

The invention discloses a non-aqueous electrolytic solution for a high-voltage lithium cobaltate lithium ion battery, which includes a non-aqueous organic solvent, an electrolyte lithium salt and an additive, and the additive includes at least one imidazolium salt compound with a specific structure or a specific structure isocyanurate compounds. The invention also discloses a lithium ion battery comprising a positive electrode sheet, a separator, a negative electrode sheet and the nonaqueous electrolyte of the high-voltage lithium cobaltate lithium ion battery. The imidazolium salt additive in the electrolytic solution of the present invention can participate in negative electrode film formation, improve negative electrode dynamic performance and thermodynamic performance, the formed passivation film resistance is low; Isocyanurate additive can under high voltage condition, in The positive electrode material interface is preferentially oxidized and decomposed to form a passivation film, which avoids the oxidative decomposition of carbonate solvents under high voltage; fluorocyanate substances as solvents can better broaden the electrochemical window of the electrolyte.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a non-aqueous electrolyte of a high-voltage lithium cobalt oxide lithium ion battery and a lithium ion battery. Background technique [0002] Lithium-ion batteries are widely used in 3C digital products due to their high operating voltage, high energy density, long life, wide operating temperature range and environmental friendliness. Nowadays, thinness and high energy density have gradually become the trend of battery development, especially for 3C digital products. With the intelligence and diversification of smart phones, people use mobile phones more and more frequently, so mobile phones are required to have more power, lighter weight, and fast charging performance. [0003] In order to improve the energy density of lithium-ion batteries, a common measure is to increase the charge cut-off voltage of the cathode material, such as the voltage of commercial lithiu...

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Problems solved by technology

[0004] However, there are certain defects in positive electrode materials at high voltages. For example, high-voltage positive electrode active materials have strong oxidative properties in the state of lithium deficiency, and the electrolyte is easily oxidized and decomposed, generating a large amount of gas and heat; The voltage cathode active material is also very unstable in the lithium-deficient state, and some side reactions are prone to occur, such as the release of oxygen, the dissolution of transition metal ions, etc.

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