Thermochemical blocking type composite positive electrode material, positive electrode plate and preparation method therefor, and lithium ion battery

Abstract

The invention relates to a thermochemical blocking type composite positive electrode material, a positive electrode plate and a preparation method therefor, and a lithium ion battery. The composite positive electrode material mainly comprises a ceramic material-coated lithium phosphate positive electrode material and a nickel-cobalt-manganese ternary material at the mass ratio of (5-95) to (5-95); in the ceramic material-coated lithium phosphate positive electrode material, the lithium phosphate is Li<y>M<x>N<1-x>PO<4>, wherein x is greater than 0 and less than 1, y is greater than or equal to 0.8 and less than or equal to 1.2, and M and N are selected from any two kinds of iron, cobalt, nickel, manganese and vanadium; and the nickel-cobalt-manganese ternary material is LiNi<1-x-y>Co<x>Mn<y>O<2>, wherein x is greater than 0 and less than 1, y is greater than 0 and less than 1, and x+y is less than 1. By virtue of the composite positive electrode material, the synergistic thermochemical blocking effect of the ceramic material and the lithium phosphate can be played, so that thermal runaway caused by failure of the positive electrode material structure can be prevented; in addition, the structural stability, the safety and the energy density of the positive electrode material of the lithium ion battery are improved; and furthermore, a simple process, a short process flow and high working efficiency are achieved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and specifically relates to a thermochemical blocking type composite positive electrode material, and also relates to a positive electrode sheet prepared by using the thermochemical blocking type composite positive electrode material and a preparation method thereof, and using the thermochemical blocking type composite positive electrode material Lithium-ion battery with positive pole. Background technique [0002] As an efficient, environmentally friendly and low-carbon new energy device, lithium-ion batteries have received extensive attention and research. At present, it has been widely used in mobile communication equipment, digital equipment and electric tools. Recently, as a very promising and promising energy storage device in the field of new energy transportation, lithium-ion batteries have been greatly promoted and applied in electric vehicles by virtue of their high speci...

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Problems solved by technology

[0006] The lithium ion battery that above-mentioned lithium ion battery positive plate is made, although utilize different active material in charging and discharging process opposite unit cell volume change characteristics, and Al 2 o 3 or SiO 2 The excellent liquid retention ability of the electrolyte improves the long-term cycle performance and safety performance of the lithium-ion battery; however, it adopts a sandwich-type multi-layer structure, and each material is distributed in different coatings, and the coupling between different materials The synergistic effect is not strong, the improvement of the overall gram capacity and structural stability of the positive electrode material is limited, and the synergistic thermochemical blocking effect cannot be exerted; at the same time, when preparing the positive electrode sheet, three different slurries need to be prepared to form three layers respectively Coating, the process is cumbersome, the process flow is long, and the production efficiency is low

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