3D Copper Foam Foil Solving The Problem Of Heavy Solid-State Batteries

(MENAFN- GetNews) Foam copper foil (also known as“3D copper foil”) is a new type of three-dimensional porous, uniformly interconnected foam metal material characterized by lightweight, high strength, and excellent electrical conductivity. In recent years, with the development of battery technology, particularly the emergence of solid-state and semi-solid-state batteries, foam copper foil has garnered significant attention and application in the field of lithium-ion battery anode current collectors. The lightweight and high specific strength characteristics offoam coppergive it a considerable advantage in the field of structural Materials.

Compared to traditional 6-micron electrolytic copper foil and composite copper foil, foam copper can effectively reduce battery weight and increase battery energy density, making it a promising core material for lightweight applications in the low-altitude economy. With the rapid development of the low-altitude economy, foam copper will provide important technical support and material assurance for this field a three-dimensional porous, uniformly interconnected metallic material, foam copper, with its low production cost and excellent conductivity, holds promise as a current collector for semi-solid/solid-state lithium-ion batteries.

According to a paper by Professor Cui Yi from Stanford University published in Nature Energy on February 28, 2024, a proposal was made to construct a porous current collector as the next-generation product of composite current collectors, which not only enhances energy density but also increases the charging rate by four times, achieving the goal of ultra-fast charging; Additionally, the porous anode current collector can be applied to silicon-based anode materials, effectively addressing the issue of silicon material collapse, thereby opening up new possibilities for further enhancing energy density in lithium batteries, particularly solid-state batteries.

Advantages of foam copper as an anode current collector material:1 High safety: no sharp edges are produced during puncture, preventing internal short circuits;2 Cost-effective, lightweight, and high energy density (copper usage is approximately 1/7 of traditional copper foil);3 Excellent ultra-fast charging performance (expected to reach 7-10C);4 Enables the use of metallic lithium anodes, facilitating the application of metallic lithium anodes and accelerating the industrialization of semi-solid/solid-state batteries. 3D copper foil can be produced using various methods, including laser or mechanical perforation, and chemical reactions to grow three-dimensional structures on the surface of the copper foil. Common methods include foaming and electroplating.

The principle of electroplating to produce foam copper involves obtaining a thin metal film through chemical plating on an organic matrix with a mesh structure (typically polyurethane resin) to impart conductivity to the matrix. A metal layer is then deposited on its surface via electroplating. Finally, the organic matrix is removed through sintering to obtain a foam metal with a three-dimensional mesh structure. Using polyurethane foam as the substrate, foam copper is prepared through pretreatment, chemical plating, electroplating, and sintering reduction processes. The morphology of the foam during preparation is observed using a scanning electron microscope (SEM), and the main physical properties of the foam copper are measured.

1. Pretreatment

(1) Degreasing: Degreasing removes oily substances from the surface of the foam material to prevent them from affecting the chemical plating process.

(2) Roughening: Roughening involves immersing the degreased foam material in a roughening solution to open the blind pores of the foam matrix and form hydrophilic groups on its surface, while increasing its surface roughness.

(3) Sensitization: Sensitization involves adsorbing a layer of reductive metal ions-stannous ions (Sn2+)-on the surface of the foam material. The main components of the sensitization solution are stannous chloride and hydrochloric acid. Sensitization temperature: 45°C, sensitization time: 5 minutes. During sensitization, tin particles should be added, and a milky white emulsion of Sn(OH)Cl forms on the foam material surface, creating a uniform adsorbed layer on the foam substrate.

(4) Activation. Activation involves forming a catalytic metal layer on the substrate surface. The activation of Pd is shown in the following equation [forming Pd nuclei from (Pd-Cl4)2]. (PdCl4)2− + Sn2+ → Pd + Sn4+ + 4Cl−.

(5) Degumming. The activated foam material is washed with a 10% hydrochloric acid solution for 1 minute to degum it. The purpose is to remove the gel layer covering the Pd surface, exposing the Pd atoms on the surface to act as a catalyst.

2. Chemical copper plating

On the catalytically active foam surface, a layer of metallic copper is deposited via a reduction reaction, imparting conductivity and enabling further electroplating.

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