A lithium negative electrode with an interfacial nanosheet protective layer and its preparation method

Abstract

The invention discloses a lithium negative electrode with an interface nanosheet protective layer, which comprises a lithium negative electrode substrate, and a graphite-phase carbon nitride nanosheet interface layer is covered on the surface of the lithium negative electrode substrate. The preparation method is as follows: adding graphite-phase carbon nitride nano-sheet powder into an organic solvent for dispersion to prepare a graphite-phase carbon nitride nano-sheet dispersion; applying the graphite-phase carbon nitride nano-sheet dispersion onto the surface of a lithium negative electrode substrate After the solvent is volatilized, an interface layer of graphite-phase carbon nitride nanosheets is formed on the surface of the lithium negative electrode to obtain a lithium negative electrode with a protective layer of interface nanosheets. In the present invention, a graphite-phase carbon nitride nanosheet interface layer is covered on the surface of the lithium negative electrode substrate, and the abundant and evenly distributed nitrogen atoms in the graphite-phase carbon nitride nanosheet can interact with lithium ions to form a transient Li-N bond , thereby regulating the flux of lithium ions and achieving a stable deposition process, which helps to reduce the formation of lithium dendrites and dead lithium, and reduce polarization.

Description

technical field [0001] The invention belongs to the field of lithium-ion battery materials, and in particular relates to a lithium negative electrode with an interface nanosheet protective layer and a preparation method thereof. Background technique [0002] Since Sony first commercialized lithium-ion batteries in 1991, lithium-ion batteries have become one of the most important technologies in current energy storage technology. Today, lithium-ion batteries have a wide range of applications in portable electronic devices, electric vehicles, and energy storage in power stations. However, after decades of development, commercial Li-ion batteries using graphite anodes have approached the limit of their theoretical energy density (~250Wh kg -1 ), cannot meet the rapid increase in energy density requirements of batteries in the field of energy storage, so there is an urgent need to develop anode materials with higher energy densities. [0003] The lithium metal anode has a high...

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Problems solved by technology

[0005] In the patent document whose publication number is CN109004276A, lithium salts, ionic liquids, inorganic nanoparticles and lithiated Nafion polymers are mixed to prepare a lithium negative electrode protective film with good stability and ion conductivity, but this method requires There are many types of materials and the process is more complicated

In the patent document with the publication number CN109148826A, a LiF layer is prepared on the surface of the lithium negative electrode by magnetron sputtering, so that it has good lithium ion conductivity, but this method requires high equipment, complex processes and is difficult to produce on a large scale

In the patent document with the publication number CN110311093A, a graphene film is introduced on the surface of the lithium negative electrode to reduce the interfacial impedance and regulate the uniform nucleation of lithium. However, graphene lacks functional groups that can interact with lithium ions. Therefore, the uniform deposition of lithium ions Weaker

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