Pre-lithiated negative plate, preparation method thereof and lithium battery

Abstract

The invention discloses a pre-lithiation negative electrode plate, a preparation method thereof and a lithium battery, and the pre-lithiation negative electrode plate comprises a negative electrode current collector, an active material layer covering the surface of the negative electrode current collector, a plurality of modification layers covering part of the surface of the active material layer, and lithium-containing layers covering the residual surface of the active material layer and the surfaces of the plurality of modification layers, the multiple modification layers are distributed on the surface of the active material layer at intervals, and the coverage rate is 30-75%. The modification layer / lithium-containing layer interface in the pre-lithiation negative electrode serves as an artificial electronic path and is responsible for stabilizing electron transmission between two phase interfaces in the pre-lithiation process, damage of interface stress fluctuation to the structure of the electronic path is avoided, the reaction depth of contact pre-lithiation is remarkably enhanced, the utilization rate of the lithium-containing layer is increased, and the service life of the lithium-containing layer is prolonged. The yield of inert lithium is reduced, and the capacity retention ratio and the cycling stability of the battery are improved.

Description

technical field [0001] The present application relates to the technical field of lithium-ion batteries, in particular to a pre-lithiated negative electrode sheet, a preparation method thereof and a lithium battery. Background technique [0002] During the first charging process of a lithium-ion battery, a solid electrolyte film (SEI film) will spontaneously form on the surface of the negative electrode, resulting in a part of the reversible loss of lithium ion capacity, which in turn manifests as a lower initial Coulombic efficiency, resulting in a vacancy in the lithium ion inventory of the positive electrode. The reversible cycle capacity of the lithium-ion battery is reduced. [0003] Contact pre-lithiation is an effective method to improve the first coulombic efficiency and cycle performance of lithium-ion batteries. Specifically, by compounding a lithium-containing layer on the surface of the negative electrode to trigger the contact pre-lithiation process of the inter...

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Problems solved by technology

[0005] This application provides a pre-lithiated negative electrode sheet, its preparation method and lithium battery, aiming to solve the problem that the lithium-containing layer cannot be fully utilized due to unstable electronic pathways during the pre-lithiated process, making it inert lithium.

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