High-voltage lithium cobalt oxide lithium ion battery non-aqueous electrolyte and lithium ion battery

Abstract

The invention discloses a high-voltage lithium cobalt oxide lithium ion battery non-aqueous electrolyte, which comprises a non-aqueous organic solvent, an electrolyte lithium salt and an additive, and the additive comprises at least one imidazole salt compound with a specific structure or an isocyanurate compound with a specific structure. The invention also discloses a lithium ion battery comprising a positive plate, an isolating membrane, a negative plate and the non-aqueous electrolyte of the high-voltage lithium cobalt oxide lithium ion battery. The imidazolium salt additive in the electrolyte can participate in negative electrode film forming, the dynamic performance and thermodynamic performance of a negative electrode are improved, and a formed passive film is low in impedance; the isocyanurate additive can be preferentially oxidized and decomposed on a positive electrode material interface under a high voltage condition to form a passive film, so that the oxidative decomposition of the carbonic ester solvent under the high voltage is avoided; and the fluorine cyanogen ester substance is used as the solvent, so that the electrochemical window of the electrolyte can be widened better.

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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