A kind of negative pole of lithium ion battery and its preparation method, application and battery

Abstract

The invention discloses a lithium ion battery negative electrode, its preparation method, application and battery. The lithium ion battery negative electrode includes an electrode layer, a lithium supplementary layer and a protective layer arranged between the electrode layer and the lithium supplementary layer; the protective layer includes a solid additive , the melting point of the solid additive is lower than the formation temperature of the lithium-ion battery or soluble in the electrolyte of the lithium-ion battery; the lithium-ion conductivity of the protective layer is less than 10 ‑3 S / cm; electrode layer includes negative electrode active material layer and current collector; negative electrode active material layer includes negative electrode active material, conductive agent and binder; conductive agent includes graphite, carbon black material, acetylene black, carbon nanotubes, carbon nanofibers At least one of them; the binder includes thermoplastic resin and / or thermosetting resin; the negative electrode active material is silicon carbon or silicon oxygen negative electrode active material; the protective layer disappears after the formation stage; The direct contact improves the safety performance of the battery, the preparation is simple, the efficiency is high, and the cost is low.

Description

technical field [0001] The invention relates to the field of new energy, in particular to a negative electrode of a lithium ion battery, a preparation method, an application thereof, and a battery. Background technique [0002] In order to overcome the low efficiency of lithium-ion batteries for the first time, the method of pre-supplementing lithium by adding a lithium layer on the negative electrode side is usually used. The existing lithium supplementation technology is mainly divided into two types. The first is to pre-lithiate the silicon-oxygen material from the material level, and the second is to roll metal lithium foil or lithium powder onto the coated negative electrode by physical methods. Pole surface. [0003] However, the above-mentioned methods have defects: pre-lithiation of silicon-oxygen materials at the material level will significantly reduce the gram capacity of silicon-oxygen materials, and the rate of improvement in the first charge and discharge effi...

AI Technical Summary

Problems solved by technology

[0003] However, the above-mentioned methods have defects: pre-lithiation of silicon-oxygen materials at the material level will significantly reduce the gram capacity of silicon-oxygen materials, and the rate of improvement in the first charge and discharge efficiency of negative electrode materials is also limited, and the second method is adopted. Due to the strong reactivity of metal lithium powder, the addition of excessive metal lithium will cause the lithium analysis of the negative electrode of the battery to cause safety problems. , before the formation, the high activity of lithium increases the safety risk of the battery

[0004] In order to prevent accidents such as fire during the pre-lithiation process, there is currently a technology to install a protective layer between the lithium supplementary layer and the negative electrode, but the use of methods such as atomic deposition often has complex processes, low processing efficiency, and high cost.

Images