Non-aqueous lithium-ion battery electrolyte and lithium ion battery

Abstract

The invention discloses a non-aqueous lithium-ion battery electrolyte and a lithium ion battery. The non-aqueous lithium-ion battery electrolyte contains electrolyte salt, a non-aqueous organic solvent and a functional additive, wherein the functional additive is selected from one or combination of multiple compounds with chemical formulae of (K)(m+4)P(m+2)O(3m+7), (L)(n / 2+2)P(n+2)O(3n+7) and (K)s(PO3)s, K is an alkali metal element selected from a first main group except hydrogen; L is an alkali metal element selected from a second main group except beryllium in the periodic table of elements; (K)(m+4)P(m+2)O(3m+7) contains an anionic group P(m+2)O(3m+7)<(m+4)->, and m is 0 or a positive integer; (L)(n / 2+2)P(n+2)O(3n+7) contains an anionic group P(n+2)O(3n+7)<(n+4)->, and n is 0 or a positive even number; (K)s(PO3)s contains an anionic group (PO3)s<s->, and s is 3 or an integer larger than 3. During first formation of a battery prepared from the non-aqueous lithium-ion battery electrolyte, a dense and uniform SEI film with high lithium ion conductivity can be formed, so that first charge-discharge efficiency of the battery is improved, and normal-temperature cycling performance, rate capability, high-temperature cycling performance, high-temperature storage performance and low-temperature discharge performance of the battery are improved.

Description

technical field [0001] The invention relates to a battery, in particular to a non-aqueous lithium ion battery electrolyte and a lithium ion battery. Background technique [0002] With the rapid development of increasingly smaller and lighter portable electronic devices, there is an increasing demand for small, lightweight, thin and high-performance batteries that provide power for these portable electronic devices. However, as the battery pursues small volume and high energy density, the compaction density of the positive and negative electrodes is continuously increased or the high-capacity negative electrode material with poor cycle performance is used, which also brings a series of performance problems of the battery, such as poor cycle performance. , Poor high temperature performance, poor low temperature performance and rate performance, easy to precipitate lithium during low temperature charge and discharge. [0003] The reason for the above defects is that a layer of...

AI Technical Summary

Problems solved by technology

However, as the battery pursues small volume and high energy density, the compaction density of the positive and negative electrodes is continuously increased or the high-capacity negative electrode material with poor cycle performance is used, which also brings a series of performance problems of the battery, such as poor cycle performance. , poor high temperature performance, poor low temperature performance and rate performance, easy to precipitate lithium during low temperature charge and discharge

[0003] The reason for the above defects is that a layer of SEI film will be formed on the surface of the negative electrode during the first charging process of the lithium-ion battery. If the SEI film formed is not dense and stable enough during the high-temperature cycle, the SEI film will gradually dissolve or rupture, causing the exposed negative electrode to continue to react with the electrolyte, consuming the electrolyte and making the battery capacity reduction

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