Positive plate, preparation method and lithium-ion battery comprising positive plate

Abstract

The invention discloses a positive plate, a preparation method and a lithium-ion battery comprising the positive plate. The positive plate comprises a current collector, an active layer formed on thecurrent collector and a conducting layer, wherein the conducting layer is formed on the active layer and the surface of the conducting layer is coated with an inert material which 0.1-30nm in thickness, wherein the active layer contains a positive active material and a lithium supplement component. The positive plate is simple in structure, stable, good in security and good in compatibility with an existing manufacturing process and has a lithium supplement function; the problems of poor solubleness and conductivity of the lithium supplement component are solved; the energy density and the rate capability of the lithium-ion battery are improved; and the cycle life of the lithium-ion battery is prolonged.

Description

technical field [0001] The invention relates to the field of lithium ions, and relates to a positive electrode sheet, a preparation method and a lithium ion battery containing the same, in particular to a lithium-rich positive electrode sheet, a preparation method and a lithium ion battery containing the same. Background technique [0002] Compared with lead-acid batteries, nickel-cadmium batteries and nickel-hydrogen batteries, lithium-ion batteries have the characteristics of high capacity density, high working voltage, good cycle performance, small self-discharge, no memory effect and environmental friendliness. , has been widely used in the 3C digital field. However, with the vigorous development of smartphones and electric vehicles, the energy density and cycle life of existing lithium-ion batteries are increasingly unable to meet their needs for high energy density and long cycle life. The actual available energy density and cycle life of the full battery are closely ...

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Problems solved by technology

[0003] CN201210350770.x directly sprays an organic solution containing lithium salt on the positive electrode sheet in an inert atmosphere, and then performs a dry treatment to supplement lithium. However, this lithium supplement method, on the one hand, flammable organic liquids are likely to cause safety hazards, and on the other hand On the one hand, a large amount of organic gases produced will pollute the air

[0004] In addition to the above-mentioned lithium supplementary method of directly adding lithium supplementary materials to the material, there are also lithium supplementary methods by designing a separate lithium supplementary layer in the anode sheet or battery structure, such as CN201310336418.5 and CN201310463949.0. It is a lithium sheet or lithium metal powder material, which has great processing safety problems, and has high reactivity with the electrolyte. This method of directly contacting the lithium supplement layer with the electrolyte cannot solve the problem of the lithium supplement in the electrolytic solution. Dissolution problem in liquid

[0005] Although CN 201410149314.8 provides a lithium-ion battery and a manufacturing method thereof, a nano protective layer of 0.2-10nm is evenly plated on the surface of the positive electrode sheet, the surface of the negative electrode sheet and the surface of the separator of the battery by the plasma-enhanced atomic layer deposition method, so as to In this way, the cycle performance and safety performance of the battery can be improved. However, directly coating the nano-inert protective layer on the surface of the pole piece and the diaphragm is easy to reduce the rate performance of the battery, and the plasma-enhanced atomic layer deposition method used is expensive.

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