Non-aqueous electrolyte and lithium ion battery containing same

Abstract

The invention relates to a non-aqueous electrolyte and a lithium ion battery containing the same. The electrolyte comprises a lithium salt, an organic solvent and additives, wherein the additives comprise cyclic annular sulphate compound and a sodium salt. When the electrolyte provided by the invention is applied to the lithium ion battery, the high-temperature cycling performance of the lithium ion battery is improved; and meanwhile, the rate capability and the low-temperature discharging performance of the lithium ion battery are greatly improved, and lithium separating out in the low-temperature charging process is lowered.

Description

technical field [0001] The present application relates to the technical field of lithium-ion batteries, in particular, to an electrolyte and a lithium-ion battery including the electrolyte. 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, the electrolyte has a significant impact on the high and low temperature performance of the battery. However, in general, there i...

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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 the electrolyte.

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, optimize the solvent composition to reduce the viscosity of the electrolyte at low temperatures and increase the 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 the batteries will usually deteriorate and cannot be finalized. Solve the problems of lithium-ion batteries in applications

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