Negative pole sheet for lithium ion battery and preparation method of negative electrode sheet

Abstract

The invention discloses a negative pole sheet for a lithium ion battery. The negative pole sheet comprises a current collector and a lithium-supplemented material sprayed on the current collector; thelithium-supplemented material comprises spun fibrous graphene and metal lithium uniformly distributed in the graphene and on the surface of the graphene; and the metal lithium distributed on the surface of the graphene is also coated with a carbon layer. According to the negative pole sheet for the lithium ion battery of the invention, an electrostatic spinning technology is adopted to directly spin graphene fibers on the negative pole sheet to supplement lithium; the obtained negative pole composite lithium-supplemented pole sheet of the lithium ion battery is stable in performance; the degree of bonding between the lithium-supplemented material and the pole sheet is high; safety performance is excellent; uniform lithium supplementation can be realized; the fibrous graphene is adopted, so that most of lithium is coated with the fibers; lithium supplementation can be continuously realized in the circulation process of the battery, so that the circulation retention rate of the batteryis improved; the first efficiency and energy density of the lithium ion battery are effectively improved; and the long circulation performance of the lithium ion battery is ensured.

Description

technical field [0001] The present application relates to the technical field of lithium-ion batteries, in particular to a lithium-ion battery negative pole piece and a preparation method thereof. Background technique [0002] Lithium-ion batteries have the characteristics of high working voltage, large specific energy, small size, light weight, and long cycle life, making them the focus of the development and competition of the automobile industry. With the continuous development of lithium-ion batteries in the fields of portable electronic devices, electric bicycles and electric vehicles, the requirements for performance such as energy density of lithium-ion batteries are getting higher and higher. [0003] During the first charging and discharging process of a lithium-ion battery, the electrode material will react with the electrolyte at the solid-liquid phase interface to form a solid electrolyte film (SEI film) passivation film, which consumes a large amount of active l...

AI Technical Summary

Problems solved by technology

At present, the common methods of lithium supplementation include in-situ doping lithium supplementation, electrochemical lithium supplementation and chemical pre-supplementation lithium method. However, the above methods have high environmental requirements and have safety hazards such as flammability, which limits the further promotion and application of each method.

[0005] CN110010860A provides a kind of composite negative electrode material that is used for lithium ion battery, comprises silicon / carbon nanotube composite fiber cloth and the carbon layer that forms on its surface, but does not contain lithium ion in this material, so although this material has higher The capacity remaining rate after cycling, but can not achieve the effect of lithium supplementation

CN105914343A provides a negative electrode sheet for lithium ion batteries. This solution adopts electrospinning technology to uniformly distribute the solution containing lithium compounds on the surface of the negative electrode sheet and dry it. However, a surfactant needs to be added to ensure uniform lithium supplementation. The charging and discharging efficiency of electrode materials containing surfactants in the prior art cannot reach the practical level

CN109301188A provides a highly dispersed lithium-ion battery supplementary lithium material and a preparation method thereof. The lithium supplementary material is a graphene sheet with metal lithium particles evenly dispersed on the surface, and the surface of the metallic lithium particles is coated with a carbon layer, but the scheme Lithium on the surface of the monolithic graphene in the medium will be crushed and detached from the graphene surface during cycling, resulting in dead lithium, which greatly reduces the effectiveness of the material

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