Lithium negative pole piece, preparation method thereof and lithium battery

Abstract

The invention provides a lithium negative pole piece, a preparation method thereof and a lithium battery. The lithium negative pole piece includes a lithium negative electrode and a protective layer which comprises a lithium carbide layer, and the lithium carbide layer is arranged on one surface of the lithium negative electrode. Therefore, the lithium carbide serving as the protective layer is arranged on the surface of the lithium negative electrode, so that the problems of falling, breakage and the like of the protective layer can be effectively prevented, the long-term effectiveness of theprotective layer is further ensured, and the coulombic efficiency of the battery and the capacity retention ratio of the battery in long-term circulation are effectively improved. The lithium carbidelayer can also inhibit the growth of lithium dendrites, so that the short circuit of the battery caused by the generation of the lithium dendrites is effectively prevented.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular, to a lithium negative pole piece, a preparation method thereof, and a lithium battery. Background technique [0002] At present, using lithium metal as the negative electrode material is a hotspot in the research of solid-state batteries. On the one hand, metal lithium is one of the negative electrode materials with the highest theoretical energy density. At the same time, metal lithium has a lower electrochemical potential, and the greater the voltage difference between positive and negative electrodes, The higher the specific energy of the battery. However, during the use of lithium metal as a negative electrode material, due to the difference in electrodeposition rate, the deposition is uneven, resulting in the formation of lithium dendrites. The generation of lithium dendrites is easy to pierce the solid electrolyte and cause a short circuit, and it will also lead to "waste l...

AI Technical Summary

Problems solved by technology

However, during the use of lithium metal as a negative electrode material, due to the difference in electrodeposition rate, the deposition is uneven, resulting in the formation of lithium dendrites. The generation of lithium dendrites is easy to pierce the solid electrolyte and cause a short circuit, and it will also lead to "waste lithium". produce, which reduces the cycle capacity; and the metal lithium negative electrode has higher requirements for solid electrolytes, and should have high ionic conductivity and good electron blocking ability, etc.

In order to effectively protect the lithium metal of the negative electrode, it is a common method to coat the protective layer on the surface of the lithium negative electrode, but the protective layer coated on the surface of the lithium metal will cause severe volumetric changes in the lithium metal negative electrode during the battery cycle. Changes lead to such problems as cracking, breaking, and falling off of the protective layer, which eventually leads to the failure of the protective layer.

[0003] Therefore, the research on the lithium negative electrode sheet needs to be deepened.

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