A kind of lithium negative pole and preparation method thereof

Abstract

The invention discloses a lithium negative electrode, which comprises a lithium negative electrode substrate, a poly-1,3-dioxopentacyclic layer is polymerized in situ on the surface of the lithium negative-electrode substrate, and graphite phases are evenly distributed in the poly-1,3-dioxopentacyclic layer Carbon Nitride Nanosheets. The preparation method is as follows: adding graphite-phase carbon nitride nano-sheet powder into 1,3-dioxane for dispersion to prepare a graphite-phase carbon nitride nano-sheet dispersion; adding graphite-phase carbon nitride nano-sheet dispersion Adding an initiator, drop-coating on the surface of the lithium negative electrode matrix, so that 1,3-dioxacycline is in-situ polymerized on the surface of the lithium negative electrode to obtain a lithium negative electrode with a composite interface layer. The present invention polymerizes 1,3-dioxane in situ on the surface of the lithium negative electrode substrate in the form of in-situ polymerization, and the in-situ polymerized poly-1,3-dioxane forms an interfacial buffer layer on the surface of the substrate, which can effectively inhibit branching. crystal growth.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, in particular to a lithium negative electrode with a composite interface protection layer and a preparation method thereof. Background technique [0002] Lithium-ion batteries are widely used in portable electronic devices, electric vehicles, and energy storage in power stations. However, limited by the energy density of graphite anodes, traditional lithium-ion batteries are difficult to meet the rapid growth of people's requirements for battery energy density. Therefore, there is an urgent need to develop anode materials with higher energy densities. The lithium metal anode has a high theoretical capacity (3860mAh g -1 ) and lower electrode potential (-3.04V vs. SHE), becoming one of the most promising anode materials for next-generation batteries. [0003] However, the high reactivity of metal lithium will continue to react with the electrolyte, resulting in the continuous formation of SE...

AI Technical Summary

Problems solved by technology

[0004] In the patent document with the publication number CN108539272A, it is disclosed that lithium nitrate and metal halide additives are added to the electrolyte to realize the rapid migration of lithium ions on the interface layer and the uniform deposition on the electrodes, but during the cycle, the additives may be consumption, the effect is not long-lasting

In the patent document with the publication number CN111293283A, a double-layer interface film is prepared on the surface of the lithium negative electrode, the inner layer is a LiF inorganic layer, and the outer layer is an ether polymer layer. This technical solution can effectively improve the cycle performance of the battery, but the interface The thickness of the film is relatively large, which may hinder the migration of lithium ions

In the patent document with the publication number CN110311093A, it introduces a graphene film on the surface of the lithium negative electrode to reduce the interfacial impedance and regulate the uniform nucleation of lithium, but graphene lacks functional groups that can interact with lithium ions, so the role of uniform lithium ion deposition weaker

In the patent document whose publication number is CN109841817A, it adds carbon nitride powder into the molten metal lithium, which improves the wettability of the lithium lanthanum zirconium oxygen inorganic solid electrolyte to lithium metal and reduces the interface impedance; but the surface of the composite lithium negative electrode is bare. Leaked metal lithium may still be prone to dendrites, and the process of melting lithium is difficult to apply to liquid batteries and polymer solid-state batteries

Images