Electrolyte additive, electrolyte and lithium ion battery

Abstract

The invention discloses an electrolyte additive, an electrolyte and a lithium ion battery. The electrolyte additive comprises barbituric acid and a cyclotriphosphazene compound, the structural formulaof the cyclotriphosphazene compound is shown in the specification, wherein R1, R2, R3, R4, R5 and R6 are respectively and independently selected from halogen, substituted or unsubstituted C1-12 alkyl, halogen substituted or unsubstituted C2-C12 alkenyl, halogen substituted or unsubstituted C6-C26 aryl or -O-R' group; and R' is selected from halogen substituted or unsubstituted C1-12 alkyl, halogen substituted or unsubstituted C2-C12 alkenyl, and halogen substituted or unsubstituted C6-C26 aryl. The electrolyte additive can be applied to a battery electrolyte, can form compact and stable passivation films at the cathode and the anode, and prevents cathode and anode active substances from directly contacting with the electrolyte, so that adverse reactions of an electrolyte solvent in cathode and anode active materials are prevented, and the cycle performance of the lithium ion battery at high temperature and high pressure is 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] Since Japan's Sony Corporation first commercialized lithium-ion batteries in 1990, the research and development of lithium-ion batteries has never stopped; at present, most 3C electronic products and power batteries use lithium-ion batteries, mainly benefiting from Because it has the advantages of high energy density, long cycle life, safety and no memory effect. However, with the progress and development of society, people's demand for lithium-ion batteries with high energy density is becoming more and more urgent. An important means to increase the energy density of lithium ions is to increase the charge cut-off voltage of the battery to increase the gram capacity of the positive electrode material, thereby increasing the energy density of the lithium ion battery. As an importan...

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Problems solved by technology

However, the conventionally used electrolyte solvent is easy to oxidize and decompose on the surface of the positive electrode under high temperature and high voltage, and the decomposition of the electrolyte will promote the deterioration reaction of the positive and negative active materials, resulting in a decrease in the cycle performance of the lithium-ion battery, especially at high temperature. Cycle performance at high voltage

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