Preparation method of lithium ion battery positive plate

Abstract

The invention discloses a preparation method of a positive plate of a lithium ion battery, which comprises the following specific steps: uniformly mixing a high-nickel positive electrode material and a magnetic material through mechanical stirring to obtain high-nickel positive electrode slurry, coating the surface of a current collector with the high-nickel positive electrode slurry, and drying to obtain the positive plate of the lithium ion battery. The magnetic material is directionally arranged in the high-nickel positive electrode slurry by alternately loading and removing a magnetic field, meanwhile, a thick polar plate with a graded multi-dimensional through channel is prepared by utilizing an ice crystal effect, and then the magnetic material in the thick polar plate is recovered by adopting a magnetic recovery device to prepare the positive plate of the lithium ion battery, and the content of Ni in the high-nickel positive electrode material is greater than or equal to 80wt%. The magnetic material is iron-doped gadolinium gallium garnet magnetic nanoparticles. The constructed thick electrode with the hierarchical multi-dimensional through channel is applied to the lithium ion battery, and the rapid charging and discharging capability of the lithium ion battery is realized on the premise of not sacrificing the utilization rate and the capacity of an active material.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a preparation method of a positive electrode sheet of a lithium ion battery. Background technique [0002] Lithium-ion batteries are the most widely used secondary batteries due to their advantages of high voltage, high energy density and long cycle life. However, with the continuous development of the miniaturization and long standby of portable electronic devices, and the activation of high-power and high-energy devices such as electric bicycles and electric vehicles, people have put forward higher and higher requirements for the energy density of lithium-ion batteries. [0003] There are many ways to improve the energy density of lithium-ion batteries: 1. From the perspective of structural design, increase the volume of the design space of the cell structure to increase the total amount of active materials; 2. From the perspective of electrochemical d...

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Problems solved by technology

However, the thick electrode design has the following problems: 1. As the thickness of the electrode increases, the coating process is not easy to dry, the bonding strength between the electrode coating and the current collector decreases, and the active material is easy to fall off. At the same time, the baking temperature of the electrode is high, and the binder The conductive agent and the conductive agent float up with the solvent, which will easily lead to poor peeling force of the pole piece and uneven distribution of the conductive agent and pores; The electrode is not completely wetted, which leads to lithium deposition at the negative electrode of the battery at high rates, resulting in potential safety hazards; 3. The increase in electrode thickness will prolong the transmission path of electrons and lithium ions, reduce the conductivity of ions and electrons, and lead to changes in rate performance and cycle performance. Poor; 4. Electrodes made by traditional granular slurry coating methods exhibit randomly distributed porosity and high tortuosity (the tortuous path for liquid electrolyte to permeate inside the electrode)

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