Electrolyte, lithium ion battery and formation method

Abstract

The invention relates to an electrolyte. The electrolyte comprises an organic solvent, a lithium salt and additives; the additives comprise ethylene sulfate, a lithium salt additive and a film forming additive; the lithium salt additive is one or a combination of more of lithium difluoro(oxalato) borate, lithium bis (oxalato) borate, lithium tetrafluoroborate and lithium difluoro bis (oxalato) phosphate; the film forming additive is one or a combination of more of vinylene carbonate, 1-3 propane sultone, vinylene carbonate, fluoroethylene carbonate and propylene sulfate. The additive combination used in the electrolyte of the invention can well inhibit the problem of battery gas production caused by addition of ethylene sulfate (DTD) in the battery formation process, greatly improves the battery production efficiency and safety, and does not influence other performances of the battery. A good protective film formed after formation can further improve the cycle and high-low temperature performance of the battery.

Description

technical field

[0001] The invention belongs to the technical field of electrochemistry, and in particular relates to an electrolytic solution, a lithium ion battery and a formation method. Background technique

[0002] As a clean and convenient energy source, lithium-ion batteries play a very important role in people's daily life. More and more electrical equipment needs to use lithium-ion batteries to provide energy for them. Formation, as an important step in the manufacture of lithium-ion batteries, is extremely critical to the performance of lithium-ion batteries. The main function of chemical formation is to form a dense protective film on the surface of the negative electrode of the battery, which can effectively prevent the co-embedding of solvent molecules and avoid the damage to the electrode material caused by the co-embedding of solvent molecules, thus greatly improving the cycle performance of the electrode and service life. Among them, vinyl sulfate (DTD) is ...

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