Lithium ion battery pre-lithiated positive pole piece and preparation method of lithium ion battery

Abstract

The invention provides a lithium ion battery pre-lithiated positive pole piece and a preparation method of a lithium ion battery, the positive pole piece comprises a current collector and a positive pole slurry arranged on the surface of the current collector, and the positive pole slurry comprises lithium nitride. The preparation method of the lithium ion battery pre-lithiated positive pole piece comprises the following steps: coating the surface of the current collector with the positive pole slurry, and carrying out drying and rolling to obtain the positive pole piece. According to the pre-lithiated positive pole piece, the coulombic efficiency of the lithium ion battery in the first week can be improved, and meanwhile, the specific energy of the battery can be kept at a relatively high level.

Description

technical field [0001] The invention belongs to the field of lithium-ion batteries, and relates to a lithium-ion battery pre-lithiated positive pole piece and a preparation method of the lithium-ion battery. Background technique [0002] At present, lithium-ion batteries occupy an indispensable position in human life. From electronic communication to transportation, both lithium-ion batteries play an energy supply role. With the improvement of people's quality of life, the capacity requirements for lithium-ion batteries are also increasing. As an important part of lithium-ion batteries, anode materials have a significant impact on the performance of lithium-ion batteries. Commercial lithium-ion battery anode materials are mainly carbon materials and silicon-carbon materials. Compared with cathode materials, anode materials have higher specific capacity, but their first-week Coulombic efficiency is usually lower, and carbon materials can reach 90%, while silicon-based mater...

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Problems solved by technology

It mainly includes three methods: negative electrode preformation, such as CN 105190958 B, CN110178252 A, CN 110521033 A, which can simulate the formation of SEI film to the greatest extent, but its operation is relatively complicated and it is difficult to realize large-scale application; adding lithium powder to the negative electrode such as CN 108321438 A, CN 110010863 A, can be added during the negative electrode pulping process, and lithium powder can also be sprayed on the surface of the negative electrode sheet. The operation is relatively simple, but the safety of lithium powder operation is difficult to guarantee; the positive electrode is added with pre-lithiated materials, such as CN 108365174 A, such as Li 2 o 2 etc. can provide abundant Li + The material can be added directly when the positive electrode is made into pulp, and the safety is relatively guaranteed, and the production equipment and process can be retained to a large extent. However, the pre-lithiated material still exists in the battery after releasing lithium ions, occupying a certain mass and reducing the its mass-to-energy

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