Preparation method of positive pole piece containing positive electrode material coated by electricity and lithium conducting composite material and lithium-ion battery

Abstract

The invention provides a preparation method of a positive pole piece containing a positive electrode material coated by an electricity and lithium conducting composite material, and belongs to the technical field of lithium-ion batteries. The preparation method comprises the steps of uniformly stirring a vinyl sulfonic acid monomer, a cross-linking agent, an initiator and a solvent, then adding apositive electrode material, removing the solvent after impregnation, reacting for 10h at a temperature of 90 DEG C to obtain a positive electrode material coated by a cross-linked polymer; preparinga mixed solution by lithium salt and a low-boiling-point solvent, adding the positive electrode material coated by the cross-linked polymer, removing the low-boiling-point solvent until sulfonate or sulfonic acid cations in a coating layer of the positive electrode material is / are converted into lithium sulfonate structure to obtain a positive electrode material coated by a lithium sulfonate cross-linked polymer electrolyte; and uniformly mixing the positive electrode material coated by the lithium sulfonate cross-linked polymer electrolyte, a binder, a lithium conducting material and a conductive agent, and then forming a positive pole piece after coating and drying. The positive electrode material has lithium ion and electricity conducting properties, and improves the performances of thelithium-ion batteries.

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 comprising a conductive lithium-conducting composite material coated with a positive electrode material and a lithium-ion battery. Background technique [0002] Due to the characteristics of no memory effect, no pollution, and long life, lithium-ion batteries have great application potential in power vehicles, digital and other fields. A lithium-ion battery is mainly composed of a positive electrode, a negative electrode, a separator, and an electrolyte. As one of the core materials of lithium-ion batteries, the cathode materials currently mainly include lithium cobaltate, lithium manganate, lithium iron phosphate, nickel-cobalt lithium manganate, nickel-cobalt lithium aluminate, etc. When the positive electrode material is in direct contact with the electrolyte during charging and discharging, there wi...

AI Technical Summary

Problems solved by technology

The Chinese invention patent application with the application number CN201811110006.9 discloses a nickel-cobalt lithium manganese oxide cathode material coated with nano-carbon composite conductive polymer and its preparation method, forming a layer of polymer on the surface of nickel-cobalt lithium manganese oxide The conductive polymer coating can improve the conductivity of the electrode material, but the coating layer has poor lithium ion conductivity, which affects the deintercalation of lithium ions and reduces battery performance

The Chinese invention patent application with the application number CN201710934133.X discloses a method for double modifying the positive electrode material with a fast ion conductor and a conductive polymer. The fast ion conductor is used as the first layer of coating and the conductive polymer is the second layer of coating. This method can effectively slow down the side reaction between the positive electrode and the electrolyte, but this method has too thick a coating layer and a high lithium ion transport barrier, which affects the performance of lithium ion batteries.