High-voltage functional electrolyte and preparation method and application therefor

Abstract

The invention belongs to the technical field of the lithium ion battery, and discloses a high-voltage functional electrolyte and a preparation method and an application therefor. The high-voltage functional electrolyte is prepared by adding a functional additive into the common electrolyte, wherein the functional additive accounts for 0.25-5% of the common electrolyte based on mass percentage; and the structural formula of the functional additive is as shown in the formula (1). The functional additive which is diethyl (thiophene-2-methyl) phosphate can be used as the high-voltage film-forming agent and the flame-retardant additive of the lithium ion electrolyte; the electrolyte containing the functional additive is non-combustible; and the room-temperature and high-temperature cycling performances of the lithium ion battery prepared from the electrolyte are both improved under 3-5.0V, so that the high-voltage functional electrolyte is wide in the application prospect.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a high-voltage functional electrolyte, a preparation method and application thereof. Background technique [0002] At present, among commercial secondary batteries, lithium-ion batteries have the highest specific energy and the best cycle performance, and because of the diversity of electrode materials, they have broad development prospects as energy storage batteries. At present, the positive electrode materials of commercial lithium-ion batteries mainly include lithium manganese oxide, lithium cobalt oxide, ternary materials, and lithium iron phosphate. The charging cut-off voltage generally does not exceed 4.2V. 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 batteries. Therefore, increasing the operating voltage of lithium-ion batteries...

AI Technical Summary

Problems solved by technology

[0004] However, while increasing the voltage of the positive electrode material, the electrochemical performance of the battery such as charge and discharge cycles is declining. On the one hand, the reason is that the structure of the spinel lithium nickel manganese oxide material is not stable due to the ginger Taylor effect; on the other hand, the electrolyte matching problem

Conventional commercial electrolytes are easy to oxidize and decompose on the surface of the positive electrode of the battery at a high potential of 5V. The oxidative decomposition reaction of the electrolyte itself will also promote malignant reactions such as morphology changes and structural collapse of the positive electrode material.

Images