Tetracyano-containing nitrile ether electrolyte additive, electrolyte and lithium ion battery

Abstract

The invention belongs to the field of electrolyte, and discloses a tetracyano-containing nitrile ether electrolyte additive, which comprises a compound of a structure as shown in a structural formula I. In the formula I, A1 is selected from one of C1-20 alkylene or halogenated alkylene and C2-20 alkenylene or halogenated alkenylene; and A2, A3, A4 andA5are independently selected from alkyleneoxy or halogenated alkyleneoxy of C1-20 and alkenyleneoxy or halogenated alkenyleneoxy of C2-20 respectively. The tetracyano-containing nitrile ether electrolyte additive has good cycle performance, high-temperature storage performance and low-temperature performance after being used in an electrolyte under high voltage. Meanwhile, the invention further discloses an electrolyte and a lithium secondary battery.

Description

technical field [0001] The invention relates to the technical field of lithium-ion batteries, in particular to a tetracyano-containing nitrile ether electrolyte additive, electrolyte and lithium-ion batteries. Background technique [0002] In recent years, lithium-ion secondary batteries have been widely used due to their high specific energy, long life, light weight, thin film and small volume. Moreover, the lithium-ion battery in the lithium cobalt oxide and nickel-cobalt-manganese ternary material system can increase the battery energy density by increasing the charging voltage. However, under high voltage, the oxidation activity of the cathode material increases while the stability decreases, which makes the non-aqueous electrolyte easy to undergo electrochemical oxidation reaction on the surface of the cathode, and then decomposes to generate gas. At the same time, the transition metal elements (such as nickel, cobalt, manganese, etc.) in the positive electrode active ...

AI Technical Summary

Problems solved by technology

However, under high voltage, the oxidation activity of the positive electrode material increases while the stability decreases, which makes the non-aqueous electrolyte easy to undergo electrochemical oxidation reaction on the surface of the positive electrode, and then decomposes to generate gas.

At the same time, the transition metal elements (such as nickel, cobalt, manganese, etc.) in the positive electrode active material will undergo a reduction reaction and dissolve, which will cause further deterioration of the electrochemical performance of the lithium-ion battery.

The above two factors will lead to a decline in the high and low temperature performance of the battery and the cycle performance under high voltage.

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