A kind of pre-lithiation process of negative pole piece

Abstract

The invention provides a pre-lithiation process for a negative electrode pole piece, which comprises: mixing 80-98% of a negative electrode active material, 0.5-8% of a binder and 0.5-10% of a conductive agent to obtain a mixture, and coating the mixture with cloth on the surface of the current collector to obtain the initial negative pole piece; the lithium foil or lithium alloy covered with the base layer is covered on the initial negative pole piece, and transferred to the surface and inside of the initial negative pole piece through microneedles to obtain a lithium-coated metal negative pole piece ; The way of microneedle transfer is selected from one or more times of rolling, extrusion or extrusion-standing; the density of microneedles is 10 to 10,000 needles / cm 2 , rolling the lithium-coated metal negative pole piece, and soaking it in the electrolyte to obtain a pre-lithiated negative pole piece. The invention does not need complicated tensioning and deviation correction devices, is simple and environmentally friendly, and has low cost. The method does not introduce any toxic substances, has a short process time, and is rich in controllable parameters. It can be pre-lithiated for different types of negative electrode materials, and has industrial application prospects.

Description

technical field [0001] The invention belongs to the field of negative pole pieces, and in particular relates to a pre-lithiation process of negative pole pieces. Background technique [0002] With the popularization of lithium-ion batteries in the fields of electronic equipment and electric vehicles, people's requirements for lithium-ion batteries are getting higher and higher. Energy density is one of the most important performance indicators of lithium-ion batteries. Its improvement means that electrical equipment will have stronger endurance, which is the focus of current research in the field of lithium-ion batteries. The most direct way to improve energy density is to use higher capacity positive and negative electrode active materials, but high capacity energy storage materials (such as silicon-based and tin-based negative electrode materials) are often accompanied by high irreversible capacity and low initial charge-discharge efficiency. , which has a great impact on...

AI Technical Summary

Problems solved by technology

The application effect of the pre-lithiated negative electrode is good, but its manufacturing method is relatively complicated, and the introduction of the reaction buffer layer will cause the increase of production cost and the loss of capacity density

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