Electrolyte and application thereof

Abstract

The invention relates to an electrolyte. The electrolyte comprises an organic solvent, lithium hexafluorophosphate and additives, wherein the additives comprise lithium tetrafluoroborate, 1,3-propane sultone, lithium bis(oxalate) borate, adiponitrile, vinylene carbonate and fluoroethylene carbonate, and in the electrolyte, the mass concentration of the lithium tetrafluoroborate is 0.5%-2%, the mass concentration of the 1,3-propane sultone is 1%-4%, the mass concentration of the lithium bis(oxalate) borate is 1%-5%, the mass concentration of the adiponitrile is 1%-3%, the mass concentration of the vinylene carbonate is 0.5%-2%, and the mass concentration of the fluoroethylene carbonate is 2%-5%. The electrolyte can be used for improving the cycle performance, the high-temperature storage performance and the initial energy density of a lithium-ion battery. The invention further provides an application of the electrolyte in the lithium-ion battery.

Description

technical field [0001] The invention relates to an electrolytic solution and its application in lithium ion batteries. Background technique [0002] The operating voltage of lithium-ion batteries is 3.7V, which is more than three times that of nickel-metal hydride batteries. At present, most handheld and mobile digital products use lithium-ion batteries. With the continuous development of digital technology and technology integration, the requirements for batteries that provide power supply energy are getting higher and higher, and longer standby and use times are required. At present, more positive and negative electrode materials with higher specific capacity and compaction performance are used to increase battery capacity, and to increase the energy density of lithium-ion batteries by improving battery space utilization. In current lithium-ion batteries that use lithium cobaltate and graphite as active materials, when the energy density exceeds 520Wh / L, due to the increa...

AI Technical Summary

Problems solved by technology

In current lithium-ion batteries that use lithium cobaltate and graphite as active materials, when the energy density exceeds 520Wh / L, due to the increase in the surface density and compaction density of the pole pieces and the use of thin diaphragms, the electrolyte in the lithium-ion battery will The uptake and retention of

Although the battery can initially have a high capacity, the cycle life of the battery is relatively reduced. At the same time, due to the reduction of the gap and the increase of the thickness of the electrode sheet, the diffusion and migration ability of lithium ions on the negative electrode sheet is reduced, and lithium precipitation is easy to occur on the surface of the negative electrode sheet. In the case that the enriched metal lithium will further consume the electrolyte, the life of the battery will be aggravated.

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