Nanometer porous CuZnAl shape memory alloy and preparation method and application thereof

Abstract

The invention discloses nanometer porous CuZnAl shape memory alloy and a preparation method and application thereof. The method comprises the steps of matching a pure Cu block, a pure Zn block and a pure Al block according to a certain mass percent, and obtaining CuZnAl alloy ingot by smelting; performing melt-spinning on the obtained CuZnAl alloy ingot under vacuum protection by a copper roller rapid quenching method to obtain ultrathin strip-shaped CuZnAl master alloy, performing corrosion processing by employing a solution containing chloride ions to obtain a nanometer porous Cu / CuZnAl material, wherein the corrosion time is 10-300 minutes, and the corrosion temperature is 0-80 DEG C; and finally, sealing the nanometer porous CuZnAl material in a high-vacuum quartz tube for thermal processing, and acquiring the nanometer porous CuZnAl material with a super-elasticity single Beta phase under a room temperature. The preparation method is high in controllability and can be used for industrial preparation of a lithium ion secondary battery electrode material, and the cycle performance of the electrode material is remarkably improved.

Description

technical field [0001] The invention relates to a preparation method and application of a nanoporous copper-zinc-aluminum shape memory alloy, which belongs to the field of nanoporous functional metal materials and lithium ion secondary batteries. Background technique [0002] Lithium-ion secondary batteries realize the mutual conversion of electrical energy and chemical energy through the intercalation and deintercalation process of lithium ions between the positive and negative electrodes. They have the characteristics of high energy density, good cycle performance, environmental protection and pollution-free, and long service life. It has attracted the attention of researchers and industries all over the world. [0003] The capacity and cycle life of lithium-ion secondary batteries are mainly determined by the positive electrode material and negative electrode material. However, the theoretical capacity of various positive electrode materials currently developed is not mu...

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Problems solved by technology

However, it is also necessary to add a higher proportion of shape memory alloy, resulting in a low capacity of the overall negative electrode material, and too much shape memory alloy will reduce the diffusion rate of lithium ions, thereby affecting its rate performance

Third, the method of constructing a three-dimensional porous current collector is to use pores to relieve volume expansion. At present, researchers have done a lot of experimental research on nanoporous copper, nanoporous nickel, or commercially used foamed copper and foamed nickel. All show that the porous structure has a certain effect on alleviating the volume expansion of high-capacity negative electrode materials, but the porous current collector matrix itself does not have the effect of buffering strain and stress. After filling more negative electrode materials, the plasticity of the pore wall will still occur after multiple cycles. Deformation or even cracking, resulting in decreased cycle performance

However, the applicant conducted in-depth research on the basis of previous research and found that the heat treatment in this invention is carried out in a vacuum tube furnace under the protection of argon or nitrogen, which cannot completely isolate the air, and the nanoporous copper on the surface of the sample is easily oxidized, hindering Diffusion of internal Zn and Al to the surface is prevented, so that a composite material mainly composed of pure Cu and containing a small amount of β phase is obtained, and a porous single β-CuZnAl shape memory alloy current collector is not obtained

Therefore, it is impossible to reflect the huge advantage of the superelasticity of shape memory alloys in the process of buffering the volume expansion of negative electrode materials.

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