Positive electrode additive of lithium battery

Abstract

The invention relates to a positive electrode additive of a lithium battery. The additive is modified maleimide modified by a combination containing amino-nitrile, annular alkali and annular acid; and after needle test on the battery prepared from the positive electrode additive, a result shows that the stability of the obtained positive electrode active material of the battery is greatly improved, and the cycle lifetime of the battery is prolonged. The positive electrode additive has the advantages that the used additive forms a protection film on the surface of the positive electrode active material, the positive electrode active material can be prevented from splitting during internal short circuit, and the battery is safer; and meanwhile, the good safe protection film is formed on the surface of the positive electrode active material, the service lifetime of the lithium battery is greatly prolonged, the cycle lifetime of the battery is also prolonged, and the self-discharging performance of the lithium battery is also greatly improved.

Description

technical field [0001] The invention relates to the field of battery materials, in particular to a lithium battery cathode additive. Background technique [0002] Lithium-ion secondary battery is a concept proposed by Armand in the 1980s. He proposed that the positive and negative electrode materials of the battery use lithium ion materials that can be stored and exchanged, and energy exchange is performed by using the ions to move back and forth during charging and discharging. [0003] In 1991, LiCoO was produced by Japan's SONY company. 2 Lithium-ion batteries are commercial lithium-ion batteries with carbon black as the positive electrode material and carbon black as the negative electrode material. Since then, lithium-ion batteries have rapidly replaced nickel-cadmium and nickel-metal hydride batteries in many fields. Lithium-ion batteries have very broad application prospects in electric vehicles and power storage. Therefore, solid-state polymer lithium-ion batteries...

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Problems solved by technology

[0004] However, the current lithium-ion batteries do not fully meet the existing needs, especially the positive electrode materials in the prior art have poor thermal stability due to their atomic structure and other reasons, resulting in poor cycle performance at room temperature or high temperature, low battery life, and insufficient safety. And other issues

[0005] In view of the above situation, the patent CN103050706B proposes a maleimide additive for lithium batteries and a corresponding positive electrode formula for lithium batteries. The additive refers to bismaleimide modified with cyanamide and melamine. The used The additive forms a protective film on the surface of the positive electrode active material, which can prevent the cracking of the positive electrode active material during internal short circuit, making the battery safer. At the same time, due to the formation of a good safety protective film on the surface of the positive electrode active material, the service life of the lithium battery is improved; but There are still some defects: (1) The cycle life of the battery is relatively low; (2) Although the service life of the battery is improved, the self-discharge performance of the battery is average

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