Composite cathode pole piece of lithium ion battery and lithium ion battery thereof

Abstract

The invention belongs to the field of lithium ion battery preparation, and particularly discloses a composite cathode pole piece of a lithium ion battery and the lithium ion battery thereof. The composite cathode pole piece is composed of a cathode pole piece, an organic lithium compound and inorganic lithium compound which are coated at both sides of the cathode pole piece. The inorganic lithium compound is a nitrogen-containing lithium compound, such as lithium nitride and lithium amide; the electronic conductivity and structural stability of the inorganic lithium compound are improved by using the nitrogen atom, and the lithium ion transmission rate during the charging and discharging processes is improved by using the lithium ion therein; the organic lithium compound, such as lithium acetate, lithium alkoxy, alkyl bislithium carbonate, can improve the compatibility between the material surface thereof and electrolyte, and the high-temperature stabilization performance; for the surface of the prepared composite cathode pole piece contains sufficient lithium ion, the cathode pole piece can avoid the formation of lithium dendrites of the lithium ion battery during the charging and discharging processes, and the improve the safety performance thereof; the prepared composite cathode pole piece is applied to the lithium ion battery, and the rate capability and safety performance of the lithium ion battery can be improved.

Description

technical field [0001] The invention belongs to the field of preparation of lithium ion batteries, in particular to a lithium ion battery composite negative pole piece and the lithium ion battery. Background technique [0002] Lithium-ion batteries are widely used in electric vehicles and other fields due to their high voltage, high energy density, long cycle life, and environmental friendliness. However, with the development of miniaturization and long standby time of portable electronic devices, and the use of high-power and high-energy devices such as electric vehicles and energy storage components, higher and higher requirements are placed on the performance of lithium-ion batteries, especially lithium-ion batteries. Ion batteries have higher energy density, safety performance and fast charge and fast discharge capabilities. [0003] During the first charging process of a lithium-ion battery, due to the formation of a solid electrolyte film (SEI film) on the surface of ...

AI Technical Summary

Problems solved by technology

[0003] During the first charging process of a lithium-ion battery, due to the formation of a solid electrolyte film (SEI film) on the surface of the negative electrode, part of the lithium migrated from the positive electrode is consumed, resulting in the loss of lithium in the positive electrode material, which not only reduces the battery capacity, but also It will cause the reduction of the battery's initial efficiency and its safety performance; at the same time, the reduction of the number of lithium ions will reduce the number of lithium ions transmitted during the fast charge and fast discharge of the lithium ion battery, thereby reducing its rate performance

In order to solve this problem, the positive electrode sheet can be improved from the following two aspects, and the negative electrode sheet can be coated to provide lithium ions for the negative electrode sheet to form SEI during charge and discharge, and improve its cycle and rate performance, such as Patent (CN 106099041 A) A lithium titanate composite negative pole piece and a lithium titanate battery, which improve the safety of lithium-ion batteries by coating the surface of the negative pole piece with a functional layer, an active material layer and a lithium metaaluminate composite layer However, although the lithium ions contained in the metaaluminate layer can increase the transmission rate of lithium ions, its composition has no effect on the improvement of the SEI film, and it will cause the surface of the pole piece to be in contact with the SEI during the charge and discharge process. Potential difference and interfacial resistance are formed between them, resulting in deviation of cycle performance

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