Composite electrode material and preparation method and application thereof

Abstract

The invention provides a composite electrode material and a preparation method and application thereof, the composite electrode material is obtained by rolling and compounding a framework material and a sheet of a lithium-boron composite material, so that the lithium-boron composite material is embedded into the framework material, and the composite electrode material is obtained; wherein the thickness of the composite electrode material is 30-500 [mu] m; the framework material is of a grid mesh structure; the lithium-boron composite material comprises the following components in percentage by mass: 65-95% of lithium, 5-35% of boron and 0-30% of other elements. The lithium-boron composite material is embedded into a stable grid mesh skeleton structure, so that the current density distribution on the surface of an electrode is uniform, the electrode is endowed with enough self-supporting strength, the deposition / dissolution behavior of lithium is regulated and controlled, the structural stability of the electrode is improved, the composite electrode material is applied to a lithium metal-based battery, and the service life of the lithium metal-based battery is prolonged. The safety performance and the cycle life of the lithium metal-based battery can be improved.

Description

technical field [0001] The invention relates to the field of negative electrode materials for lithium batteries, and more specifically, to a composite electrode material and a preparation method and application thereof. Background technique [0002] With the depletion of fossil fuels and the increasingly prominent global climate problems caused by it, it has become a consensus to reduce carbon emissions and achieve carbon neutrality by vigorously developing clean energy such as wind, light, and hydropower. However, due to the severe influence of regions and seasons, these energy sources are often difficult to be utilized in a timely and efficient manner. The development of high specific energy secondary energy storage devices will help the further promotion of these intermittent energy sources, making them benefit more fields and regions. As the most common energy storage device for smart mobile electronic devices and electric vehicles on the market, secondary lithium-ion b...

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Problems solved by technology

However, most of the lithium-boron fibers in lithium-boron composites are relatively small (0.5-2 μm). After a large amount of free lithium is dissolved, the lithium-boron fibers that lose the "glue" of metal lithium collapse and accumulate, gradually losing their stability.

[0005] Chinese patent application CN107863488A discloses that the lithium wire is woven into a porous lithium mesh and coated with a lithium compound protective layer on the surface of the lithium mesh by magnetron sputtering, evaporation or vapor coating methods to form a support structure for a composite lithium metal mesh. It has a certain effect on improving the pulverization and structural deformation of the lithium negative electrode during cycling, but the process operation is difficult, and it is difficult to adapt to the deformation during large-capacity cycling, and its skeleton structure is still lithium metal, so the improvement effect is not very ideal; Chinese patent application CN109309243A discloses using porous carbon material as a carrier, adding molten lithium / lithium alloy to porous carbon to form a composite pole piece, so as to improve the affinity between metal lithium and carbon skeleton, and improve the lithium loading capacity of carbon skeleton. The composite negative electrode obtained by this method The carbon skeleton in Li-B still has the same collapse problem as lithium-boron fibers. In high-load lithium-sulfur batteries and other high-negative surface capacity applications, this type of discontinuous skeleton structure is difficult to maintain stability.

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