Pre-lithiation process of negative pole piece

Abstract

The invention provides a pre-lithiation process of a negative pole piece, which comprises the following steps: mixing 80-98% of a negative active substance, 0.5-8% of a binder and 0.5-10% of a conductive agent to obtain a mixture, and coating the surface of a current collector with the mixture to obtain an initial negative pole piece; covering the initial negative pole piece with the lithium foilor lithium alloy coated with the base layer, and transferring the initial negative pole piece to the surface and the interior of the initial negative pole piece through a microneedle to obtain a lithium-coated metal negative pole piece; wherein the microneedle transfer mode is selected from one or more times of grinding, extrusion or extrusion-standing; wherein the density of the microneedles is 10-10,000 needles / cm<2>, and rolling the lithium-coated metal negative pole piece, and infiltrating the lithium-coated metal negative pole piece into the electrolyte to obtain the pre-lithiated negative pole piece. A numerous tensioning and deviation rectifying device is not needed, and the pre-lithiation process is simple, environmentally friendly and low in cost. According to the pre-lithiation process, no toxic substance is introduced, the process time is short, controllable parameters are rich, pre-lithiation can be carried out on different types of negative electrode materials, and the pre-lithiation process has an industrial application prospect.

Description

technical field [0001] The invention belongs to the field of negative pole pieces, in particular to a pre-lithiation process of negative pole pieces. Background technique [0002] With the popularity of lithium-ion batteries in electronic equipment and electric vehicles, people have higher and higher requirements for lithium-ion batteries. As one of the most important performance indicators of lithium-ion batteries, the improvement of energy density means that electrical equipment will have stronger battery life, which is the focus of current research in the field of lithium-ion batteries. The most direct way to increase 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. , has a great impact on the cycle life of the battery. [00...

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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