Positive plate of lithium ion battery, lithium ion battery and preparation method of lithium ion battery

Abstract

The invention provides a positive plate of a lithium ion battery. The positive plate comprises a positive current collector and a positive active substance layer, wherein the positive active substance layer is coated on the positive current collector and contains a positive active substance, a conductive agent, a binding agent and a lithium-rich compound, and the lithium-rich compound decomposes to generate lithium ions and release one or more of a gas, conductive carbon and a substance having electrochemical lithium storage activity during formation charging of the lithium ion battery. The generated lithium ions are transferred to a negative electrode from a positive electrode and take participation in reaction with the negative electrode (react with a decomposed product of an electrolyte to form an SEI film at the negative electrode) to supplement to lithium required for forming the SEI film, thus, the lithium ion consumption of the positive active substance can be reduced, and the energy density and the cycle performance of the lithium ion battery are improved. The invention also provides a preparation method for the positive plate of the lithium ion battery, the lithium ion battery applying the positive plate of the lithium ion battery and a preparation method of the lithium ion battery.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery positive plate, a lithium ion battery using the lithium ion battery positive plate and a preparation method thereof. Background technique [0002] The positive electrode material is the sole (or main) provider of lithium ions in lithium-ion batteries. The specific capacity of lithium-ion battery cathode materials is generally 120-160mAhg -1 . In order to obtain a higher specific capacity, the current trend is to charge the positive electrode material to 4.3V or even 4.5V (LiFePO 4 , LiMn 2 o 4 It is enough to charge the cathode-like material to 4.2V, but the spinel LiNi 0.5 mn 1.5 o 4 and olivine-structured LiCoPO 4 The lithium-ion battery that is the positive electrode active material will be charged to 4.7-4.8V). The current negative electrode material is graphite (capacity can reach 360mAhg -1 ) materials, but the futur...

AI Technical Summary

Problems solved by technology

However, the physical and chemical properties of these materials are not stable enough (such as Li 3 N), making the preparation process of the cathode sheet complicated, or the amount of lithium ions that can actually be contributed by itself is low, and the material cost is high (such as lithium squarylium salt, lithium oxalate, lithium hydrazide salt)