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 an application thereof, and the method comprises the following steps: (1) mixing inert lithium powder, a binder and an organic solvent to obtain lithium powder slurry; (2) coating the lithium powder slurry on a screen printing plate on the surface of a negative plate, and removing redundant slurry on the screen printing plate; (3) drying the negative plate obtained in the step (2), and removing the screen printing plate; and (4) rolling the negative plate obtained in the step (3) to obtain the pre-lithiated negative plate. According to the method, the inert lithium powder is dispersed by adopting a wet method, so that the environmental and safety problems caused by a dry method are avoided, and meanwhile, the inert lithium powder forms dispersed islands one by one by utilizing silk-screen printing, so that the inert lithium powder can be uniformly dispersed, and excessive coating weight caused byadopting a continuous coating process can be avoided; and the problems of lithium precipitation, over-high cost, energy density reduction and the like are easily caused.

Description

technical field [0001] The invention belongs to the technical field of lithium batteries, and in particular relates to a pre-lithiated negative electrode sheet and a preparation method and application thereof. Background technique [0002] As the functions of electronic products in the consumer market are becoming more and more complete, and consumers spend more and more time using electronic products. In the field of electric vehicles, short cruising range is still a major pain point that limits the popularity of electric vehicles. These market demands require batteries to develop towards high energy density. This trend requires the next generation of batteries to use higher capacity electrode materials. Among them, the transformation of negative electrode materials from graphite to silicon-based materials can significantly increase the energy density of power batteries. However, due to the volume effect of silicon materials in the charge-discharge cycle process, the cur...

AI Technical Summary

Problems solved by technology

Dry pre-lithiation mainly adopts electrostatic adsorption and vibration spraying, but there is a phenomenon of lithium powder floating. A large amount of lithium powder floating in the air not only poses a great safety hazard, but also is harmful to the health of operators.

Then try to use wet process to disperse the lithium powder. Although the problem of lithium powder floating is solved, because there is no effective coating method, the coating thickness will increase to more than the particle size of lithium powder (D50)

Using this method will inevitably increase the thickness of the lithium powder layer, and the control of lithium powder addition cannot be accurately grasped, and it is easy to over-pre-lithiate

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