Electrolyte for battery, preparation method and application thereof, and lithium ion battery containing the same

Abstract

The invention provides an electrolyte solution for a battery, its preparation method and application, and a lithium-ion battery containing it. The electrolyte solution includes an inorganic lithium salt, an electrolyte solution solvent, and a functional additive. The structural formula of the functional additive is as shown in formula I. Show. The functional additive provided by the present invention can be oxidized and decomposed in advance before the electrolyte is decomposed to form a stable positive electrode-electrolyte interface film. The formation of the interface film can promote the diffusion of lithium ions, and avoid continuous contact between the electrode material and the electrolyte, preventing The electrolyte decomposes while reducing the damage to the structure of the electrode material, thereby effectively reducing the generation of irreversible capacity, improving the cycle stability of the battery, and making it suitable for the application of high-voltage lithium-ion batteries.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and relates to a battery electrolyte, a preparation method and application thereof, and a lithium ion battery containing the same. Background technique [0002] With the rapid development of the economy, the energy crisis has become increasingly fierce; fossil energy sources such as oil and coal are facing depletion, and people are trying their best to seek cleaner and sustainable energy to delay the arrival of the energy crisis. Since entering the 21st century, electronic information technology has brought us unprecedented convenience. At present, the electronic equipment and new energy automobile industry are developing rapidly, and the power supply is their driving source, which requires the batteries used to have a high capacity density. [0003] Lithium-ion batteries have become the main choice of batteries due to their outstanding advantages such as high energy density, low self-discha...

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Problems solved by technology

[0004] CN106558731A discloses a lithium-ion battery electrolyte and a lithium-ion battery. The lithium-ion battery electrolyte is a liquid containing lithium salt and an organic solvent; wherein, the electrolyte also contains a high-pressure additive, and the high-voltage additive includes phosphate triesters Organic matter and / or phosphite triester organic matter, the molecular structures of the phosphite triester organic matter and the phosphite triester organic matter each independently have at least one cyanophenyl group, which improves the high-voltage resistance of the lithium-ion battery sex, but the cost is higher

CN108232284A provides a high-voltage lithium-ion battery electrolyte and a lithium-ion battery using the electrolyte, which includes a non-aqueous organic solvent, a lithium salt, a functional auxiliary agent 1 and a functional auxiliary agent 2, and the functional auxiliary agent 1 is trifluoro Toluyl nitrile, the second functional additive is a fluorophosphazene compound, which improves the cycle stability of the electrolyte under high pressure, but the degree of improvement is not enough

CN107293789A discloses a lithium-ion battery with a good cycle effect and its electrolyte, including organic solvents, lithium salts and additives; the additives include monoisocyanate-based alkoxysilane compounds and film-forming compounds, and the two interact synergistically. A stable SEI film is formed on the surface of the electrode material to avoid the decomposition of the electrolyte on the electrode surface, but the cycle performance of the final battery is still not good enough to meet the application requirements of high-voltage lithium-ion batteries

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