Electrolyte and lithium ion battery comprising same

Abstract

The invention relates to electrolyte and a lithium ion battery comprising the same. The electrolyte comprises an organic solvent, a lithium salt and an additive, wherein the additive comprises a nitrogen-containing heterocyclic ring-boron trifluoride coordination compound and a sultone compound, and a nitrogen-containing heterocyclic ring is selected from at least one of a pyridyl-containing heterocyclic ring, a pyridazinyl-containing heterocyclic ring, a pyrimidinyl-containing heterocyclic ring, a pyrazinyl-containing heterocyclic ring, a pyrryl-containing heterocyclic ring, a pyrazolyl-containing heterocyclic ring and an imidazolyl-containing heterocyclic ring. The electrolyte simultaneously comprises the nitrogen-containing heterocyclic ring-boron trifluoride coordination compound and the sultone compound, so that the cycling performance of the lithium ion battery at a normal temperature and a high temperature and the storage performance of the lithium ion battery at a high temperature can be improved.

Description

technical field [0001] The present application relates to the field of batteries, in particular to an electrolyte and a lithium ion battery comprising the electrolyte. Background technique [0002] At present, the positive electrode active materials used in lithium-ion batteries mainly include lithium manganate, lithium cobaltate, ternary materials, lithium iron phosphate, etc. Under normal circumstances, the lithium-ion battery with the above-mentioned positive electrode materials The charging cut-off voltage of the lithium-ion battery does not exceed 4.2V, but with the advancement of technology and the continuous development of the market, it is increasingly important and urgent to increase the energy density of lithium-ion batteries. An effective way to increase the energy density of lithium-ion batteries is to develop high-voltage Lithium Ion Battery. [0003] However, under the high voltage of 4.6V, the conventional electrolyte will be oxidized and decomposed on the su...

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Problems solved by technology

[0003] However, under the high voltage of 4.6V, the conventional electrolyte will be oxidized and decomposed on the surface of the positive electrode of the battery. The oxidative decomposition of the electrolyte itself will also promote the deterioration of the positive active material, which will further affect the performance of the lithium-ion battery, such as storage. performance and cycle performance

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