Organic lithium-philic composite negative electrode taking three-dimensional conductive carbon material as substrate and preparation method of organic lithium-philic composite negative electrode

Abstract

The invention discloses an organic lithium-philic layer composite negative electrode taking a three-dimensional conductive carbon material as a substrate. The organic lithium-philic layer composite negative electrode is prepared by the following steps: firstly, performing surface oxidation modification treatment on the three-dimensional conductive carbon material; then carrying out amidation reaction on the modified three-dimensional carbon material and tetraamino phthalocyanine, and modifying the surface of the carbon material with the tetraamino phthalocyanine; and finally, carrying out high-temperature molten lithium deposition in a protective atmosphere to prepare the organic lithium-philic layer composite negative electrode. The lithium metal battery negative electrode material is subjected to multi-scale design, rich lithium-philic active sites are manufactured on a lithium deposition substrate material, interface lithium ion flow is dispersed by utilizing lithium-philic groups,uniform deposition / dissolution of Li < + > is guided, growth of lithium dendrites is effectively inhibited, meanwhile, structural stress change caused by a volume effect in a circulation process is reduced, and the lithium metal battery negative electrode material is obtained. And the safety and the cycle performance of the lithium metal negative electrode are effectively improved.

Description

technical field [0001] The invention belongs to the technical field of lithium batteries, and in particular relates to an organic lithium-philic composite negative electrode based on a three-dimensional conductive carbon material and a preparation method thereof. Background technique [0002] With the rapid development of electric vehicles and energy storage devices, people have higher and higher requirements for the mileage and safety of lithium batteries. The research on lithium batteries with high energy density and excellent electrochemical performance is more practical. Among the numerous negative electrode materials for lithium batteries, metal lithium due to its low density (0.534g cm -3 ), high theoretical specific capacity (3860mAh g -1 ) and low potential (-3.04V, relative to the standard hydrogen electrode) are considered to be the most ideal lithium battery anode materials. Lithium metal is an alkaline metal with the smallest ionic radius among all metals, whic...

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Problems solved by technology

To construct an artificial SEI film, it is not only necessary that the prepared SEI film has sufficient toughness to adapt to the stress generated during lithium deposition, but also requires that the prepared film layer is uniform and dense everywhere to prevent Li + Inhomogeneous deposition of the SEI film. At present, the preparation process of this method is complex and the operation is cumbersome; the strategy of optimizing the electrolyte is to enhance the uniformity and stability of the SEI film by introducing necessary additives, but too many additives will cause the lithium metal negative electrode to be damaged. The burden reduces the specific capacity, and the solvation effect will increase the side reactions, which is not conducive to Li + uniform deposition of

As an indispensable component of the battery, the separator can improve the Li + Concentration distribution, but the ionic conductivity and mechanical strength caused by the modification of the diaphragm need to be further studied and resolved

Uniform Li + The structure design of the flow negative electrode is to reduce the current density by increasing the contact area between the lithium negative electrode and the electrolyte, so that the Li + A common method for more uniform distribution, but it is difficult to be practical due to the low lithium storage capacity of the lithium deposition substrate material used

Although the above strategies are effective in solving the lithium dendrite problem and guiding Li + Uniform deposition plays a certain role, but these methods still have a lot of gaps from the requirements of commercial lithium batteries

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