Pre-lithiated negative plate as well as preparation method and application thereof

Abstract

The invention discloses a pre-lithiated negative plate as well as a preparation method and application thereof, and the method comprises the following steps: (1) mixing a binder, inert lithium powderand an organic solvent to obtain inert lithium powder dispersion liquid; (2) printing the inert lithium powder dispersion liquid on a negative plate in an ink-jet printing manner; and (3) drying and rolling the negative plate obtained in the step (2) to obtain the pre-lithiated negative plate. The pre-lithiated negative electrode is obtained by uniformly dispersing, drying and rolling the metal lithium powder on the negative electrode plate by adopting an ink-jet printing method, the first cycle efficiency and the capacity of the negative electrode material can be remarkably improved, and themethod has the advantages of continuity, low cost, material saving, expandability, controllable lithium supplementing amount, controllable lithium supplementing shape and the like.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a pre-lithiated negative electrode sheet, a preparation method and application thereof. Background technique [0002] Lithium-ion batteries are widely used due to their advantages such as high working voltage, large specific energy, small size, light weight, long cycle life, low self-discharge, no memory effect, and no pollution. They are currently a research hotspot in the field of energy storage. In recent years, with the rapid development of new energy vehicles, smart grids, and distributed energy storage, higher requirements have been placed on the energy density of energy storage devices. [0003] In order to further increase the energy density of batteries, high-capacity anode materials (such as silicon-based, tin-based, and metal oxides, etc.) have been introduced into lithium-ion batteries. However, unlike lithium ion intercalation reaction nega...

AI Technical Summary

Problems solved by technology

It is also more convenient and direct to carry out "dry spraying" lithium powder on the surface of the negative electrode to replenish lithium in practical applications. However, due to the large dust in this method, there is a great potential safety hazard; The fluctuation range of pre-lithiation is wide and it is difficult to control

Someone dissolves lithium powder in an organic solvent and sprays it on the surface of the negative electrode. Although this wet spraying effectively solves the dust problem encountered in dry spraying, the density of lithium powder is small and it is easy to float, so it is directly added to the solvent. Difficult to disperse evenly in

At present, lithium supplementation with lithium powder still has problems such as dispersion difficulty, poor uniformity of lithium supplementation, and difficulty in controlling the amount of lithium supplementation, which may easily cause uneven distribution of lithium powder on the surface of the pole piece after lithium supplementation with lithium powder, and large interface impedance. , when the lithium-ion battery is charging, there is insufficient lithium intercalation space in the negative electrode, Li + The resistance of the embedded negative electrode is too large, and the Li + Too fast deintercalation from the positive electrode but unable to embed the negative electrode in the same amount, and unable to embed Li in the negative electrode + Electrons can only be obtained on the surface of the negative electrode, thereby forming a silver-white metallic lithium element, forming lithium dendrites, and causing lithium precipitation.

Lithium analysis not only greatly reduces the effect of lithium powder pre-lithiation, but also reduces the performance of the battery and greatly shortens the cycle life. It also limits the fast charging capacity of the battery and may cause safety problems such as combustion and explosion.

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