Lithium ion battery cathode plate, lithium ion battery and preparation method of lithium ion battery

Abstract

The invention discloses a lithium ion battery cathode plate. The lithium ion battery cathode plate comprises a cathode current collector and a cathode active material layer, wherein the cathode active material layer is distributed on the cathode current collector and contains a cathode active material, a conductive agent, an adhesive agent and a lithium compound; the lithium compound is decomposed to release lithium and gas in the formation and charging processes of a lithium ion battery. The lithium compound serves as a lithium supplementation material, a cathode potential is unchanged, the lithium compound is decomposed only in the formation and charging processes, the gas generated by decomposition can be removed in the formation process, the lithium generated by decomposition is transferred from a cathode to an anode in the charging process, a solid electrolyte inter-phase (SEI) membrane is formed on the anode, and the lithium required by forming of the SEI membrane is supplemented. Therefore, the consumption of cathode lithium ions can be reduced, the irreversible capacity of the lithium ion battery is reduced, and the cycle performance of the lithium ion battery is improved. The invention also discloses the lithium ion battery with the lithium ion battery cathode plate and a preparation method of the lithium ion battery.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries. More specifically, the invention relates to a lithium ion battery cathode sheet, a lithium ion battery using the lithium ion battery cathode sheet and a preparation method thereof. Background technique [0002] Typically, lithium-ion battery systems are assembled in a discharged state, so only lithium ions are stored at the positive electrode. However, for anode materials with potentials lower than 0.8V such as silicon and graphite, about 5%-10% of lithium will be consumed due to the formation of an SEI film during cycling, which means that there will be corresponding cathode materials that will contribute A dead material that does not contribute to the cycling of lithium ions. [0003] The capacity of the positive electrode material is generally 120-160mAh / g, the capacity of graphite can reach 360mAh / g, and the theoretical capacity of silicon is 4200mAh / g. It consumes more lithium...

AI Technical Summary

Problems solved by technology

However, supplementing the anode with lithium will bring many problems, such as the exfoliation of graphite

In addition, after adding lithium, the potential of the pole piece will drop to 0V, which is easy to cause many side reactions, and the use of lithium metal has very high requirements for the process.