Non-aqueous electrolyte and lithium ion battery

Abstract

The invention provides a non-aqueous electrolyte and a lithium ion battery. The non-aqueous electrolyte comprises a non-aqueous organic solvent, a lithium salt and additives, wherein the additives comprise fluoroethylene carbonate, lithium tetrafluoroborate and a compound as shown in the structural formula 1, wherein in the formula 1, each of the R1-R4 is selected from one kind of H, halogen and saturated and unsaturated alkyl carbon chain with 1-10 carbon atoms; the alkyl carbon chain can be replaced by O or halogen; and the halogen is selected from F, Cl or Br. By virtue of the non-aqueous electrolyte provided by the invention, the high-temperature storage performance of the lithium ion battery can be ensured while the low-temperature cycling performance, the rate discharging performance and the safety performance of the lithium ion battery can be remarkably improved.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a nonaqueous electrolytic solution and a lithium ion battery. Background technique [0002] The high energy density, long cycle life, wide operating temperature range, and environmental protection of lithium-ion batteries have made them the main energy source for mobile electronic devices. With the widespread application of lithium-ion batteries, higher requirements are put forward for their environmental adaptability. Nowadays, electronic products sometimes need to be used under extreme conditions, such as environments with high or low temperatures. However, the performance of lithium-ion batteries will deteriorate significantly when used under extreme conditions. [0003] As an important part of lithium-ion batteries, non-aqueous electrolyte has a significant impact on the high-temperature performance and low-temperature performance of the battery. However, in general, there is a con...

AI Technical Summary

Problems solved by technology

However, in general, there is a contradiction between improving the high-temperature performance and low-temperature performance of lithium-ion batteries from the perspective of non-aqueous electrolytes.

On the one hand, the high-temperature performance can be improved by adding film-forming additives to passivate the positive-negative interface, but the low-temperature performance of lithium-ion batteries is severely deteriorated due to the simultaneous increase of the positive-negative interface resistance.

On the other hand, optimizing the composition of non-aqueous organic solvents reduces the viscosity of non-aqueous electrolytes at low temperatures and increases electrical conductivity. For example, by adding a large amount of low-viscosity solvents, the low-temperature performance of lithium-ion batteries can be improved, but the high-temperature performance of lithium-ion batteries is usually It will become worse and cannot finally solve the problem of lithium-ion batteries in applications

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