Three-dimensional graded porous current collector and preparation method thereof

Abstract

The invention provides a preparation method of a three-dimensional graded porous current collector. The preparation method comprises the following steps: S1) mixing a conductive agent, an adhesive, a conductive polymer material modified pore-forming agent and a solvent to obtain slurry; he.and S2) coating the surface of a current collector with the slurry, drying, and removing the pore-forming agent to obtain the three-dimensional graded porous current collector. The decomposition temperature of the conductive polymer material is higher than that of the pore-forming agent. Compared with the prior art, the shape of the three-dimensional structure and the pore size can be regulated and controlled by changing the type of the pore-forming agent, so that lithium electrodeposition in a pore channel cavity is facilitated; by adopting the pore-forming agent modified by the conductive polymer material, electron-rich groups with defect chemical sites, pyridine nitrogen, pyrrole nitrogen and the like can be synthesized in situ in a pore channel in a three-dimensional current collector, and the affinity to lithium ions is increased, so that the lithium ions can be further guided to be deposited in the three-dimensional pore channel, and the pore-forming agent is favorably applied to an actual battery system; and the current collector can be used for lithium metal battery negative electrodes and lithium-free negative electrodes.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a three-dimensional hierarchical porous current collector and a preparation method thereof. Background technique [0002] The global energy crisis and environmental degradation have accelerated the development of green energy technologies, which in turn have drawn widespread attention to green energy storage technologies including lithium-ion batteries (LIBs). Since the 1990s, the commercialization of LIBs has greatly promoted the development and popularization of portable electronic products including notebooks and mobile phones. However, in recent years, with the rapid development of electric vehicles and other advanced portable electronic products, the current lithium-ion batteries have gradually been unable to meet their needs. In this context, high energy density batteries have become a current research hotspot, and related research results have re...

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Problems solved by technology

[0004] Traditional three-dimensional current collectors for lithium metal, such as nickel foam and copper foam, are heavy in mass, which is not conducive to the improvement of energy density; three-dimensional current collectors can also be constructed by growing copper oxide nanosheets or copper nanowires on planar current collectors such as planar copper foil , but the preparation process is complicated and requires chemical treatment, especially the hydrogen reduction is required in the preparation process of copper nanowires, which is not conducive to large-scale preparation; the three-dimensional carbon skeleton can also be used as a carbon-based three-dimensional current collector such as three-dimensional graphene, three-dimensional carbon foam etc., but the same preparation process is cumbersome, requires high temperature preparation, and the preparation scale is small, which is not conducive to practical application, and most of the three-dimensional skeleton current collectors, lithium deposition only occurs on the upper surface of the current collector, it is difficult to make full use of the three-dimensional skeleton. Lithium and electrolyte can be in direct contact to consume electrolyte

The internal resistance of the battery increases and the capacity decays

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