Lithium ion battery non-aqueous electrolyte, lithium ion battery and manufacturing method

Abstract

The present invention discloses a lithium ion battery non-aqueous electrolyte, which comprises an electrolyte lithium salt, a non-aqueous organic solvent and an additive, and according to the mass percentage content in the lithium ion battery non-aqueous electrolyte, the additive comprises a component A, a component B and a component C, and the component A accounts for 0.1-3%; the component B accounts for 10%-80%; the content of the component C is 0.1%-3%; the component B can improve the oxidative decomposition potential of the electrolyte, can form a passivation film on the surface of the negative electrode, and improves the cycle performance of the electrolyte; the component A can effectively inhibit the precipitation of cobalt from the lithium cobalt oxide positive electrode, and the component C can form a sulfur-containing compound on the negative electrode to improve the morphology of the negative electrode passivation film and effectively reduce the impedance of the negative electrode passivation film. The invention provides a lithium ion battery non-aqueous electrolyte which is good in high-temperature cycle characteristic, low in gas production in high-temperature storage and good in low-temperature performance. The invention further provides a lithium ion battery comprising the lithium ion battery non-aqueous electrolyte and a manufacturing method for manufacturing thelithium ion battery.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery electrolyte, in particular to a lithium-ion battery non-aqueous electrolyte, a lithium-ion battery and a manufacturing method. Background technique [0002] With the development of mobile technology, people have higher requirements on the performance of consumer lithium-ion batteries, and it is necessary to develop higher-performance lithium-ion batteries. [0003] At present, in order to improve the performance of lithium-ion batteries, an effective method is to increase the working voltage of the battery to increase the energy density of the battery. However, the existing common commercial electrolytes are suitable for 4.4V-4.45V systems, such as carbonate electrolytes, and carbonate compounds are prone to oxidative decomposition when working at a voltage of 4.45V-4.5V. On the one hand, its Part of the product will be deposited on the surface of the electrode, increasing the impedan...

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Problems solved by technology

However, the existing common commercial electrolytes are suitable for 4.4V-4.45V systems, such as carbonate electrolytes, and carbonate compounds are prone to oxidative decomposition when working at a voltage of 4.45V-4.5V. On the one hand, its Part of the product will be deposited on the surface of the electrode, increasing the impedance of the battery and seriously deteriorating the electrochemical performance of the battery. On the other hand, the gas generated by the decomposition will cause the battery to bulge and bring potential safety hazards. Stability under V), a current practical method is to add fluorinated solvents (typically such as DFEA) in this type of electrolyte to reduce the decomposition rate of the electrolyte under high voltage

[0004] According to literature reports (Electrochemistry Communications 44(2014) 34–37), some fluorocarbonate solvents can significantly improve the high-temperature cycle performance of high-voltage lithium-ion batteries, but there are the following disadvantages, although the high-temperature performance of lithium-ion batteries using such solvents The cycle performance is improved, but the gas production is more serious when the battery is stored at a high temperature above 60 ° C, causing obvious safety hazards

[0005] International Publication Patent WO2016 / 02589A1 discloses that adding fluorocarboxylate as electrolyte solvent can improve the high-temperature cycle performance of high-voltage lithium-ion batteries, but there are the following disadvantages, such compounds will aggravate the expansion of batteries during high-temperature storage, resulting to security risk

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