Negative electrode sheet and secondary battery

Abstract

The application provides a negative electrode sheet and a secondary battery. The negative electrode sheet includes a negative electrode collector and a negative electrode membrane disposed on the negative electrode collector, and the negative electrode membrane includes a first coating and a second coating. The first coating is located on the outermost layer of the negative electrode membrane and includes a first negative electrode active material, the first negative electrode active material includes a silicon-based material and a carbon material, and in the first coating, the The mass percent content of the silicon-based material is 0.5%-10%. The second coating layer is disposed between the first coating layer and the negative electrode current collector and includes a second negative electrode active material, the second negative electrode active material includes a silicon-based material and a carbon material, and in the first In the second coating layer, the mass percentage of the silicon-based material is 5%-50%. The secondary battery of the present application can have the characteristics of high specific energy, high initial charge and discharge efficiency, good cycle performance and good safety performance.

Description

technical field [0001] The present application relates to the field of batteries, in particular to a negative electrode sheet and a secondary battery. Background technique [0002] In recent years, the field of new energy vehicles has developed rapidly, and power batteries have attracted the attention and favor of major automobile manufacturers around the world. As car companies have higher and higher requirements on the specific energy of power batteries, it is imperative to develop electrode active materials with higher specific energy. Common negative electrode active materials are mainly graphite, but its theoretical specific capacity is only 372mAh / g, and the actual specific capacity of commercial artificial graphite and natural graphite is close to its theoretical specific capacity, which cannot be further improved, thus limiting The specific energy of the power battery is improved. Therefore, it is necessary to develop new negative electrode active materials with hi...

AI Technical Summary

Problems solved by technology

However, silicon-based materials have large volume expansion during charging, and silicon-based materials also have the problem of low initial charge and discharge efficiency, resulting in low initial charge and discharge efficiency of power batteries.

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