Intermediate structure and preparation method therefor, and lithium secondary battery electrode and preparation method therefor
An intermediate structure is used for the preparation of a lithium secondary battery electrode on one side and/or on both sides. The preparation method for an intermediate structure includes the following steps: laminating a film on one side and/or on both sides of a substrate, and forming through holes in the film, the central axis of the through holes being perpendicular to the plane of the substrate; wherein, the substrate is a conductive substrate, and the film is a flexible polymer film; growing conductive materials in the through holes to form a one-dimensional columnar structure perpendicular to the substrate in the through holes; and removing the film to obtain an intermediate structure.
1 . A preparation method for an intermediate structure, wherein the intermediate structure is used for preparing a lithium secondary battery electrode on one side or both sides of the intermediate structure, the preparation method for the intermediate structure comprises steps of:
synthesizing a template: subjecting a film to an ion track etching process to obtain a through holes; pre-plating a first metal layer on the film formed with through holes by physical vapor deposition; plating a second metal layer on the first metal layer to form a substrate such that the film formed with the through holes is plated onto the substrate to form the template; wherein, central axes of the through holes being perpendicular to a plane of the substrate, the substrate is a conductive substrate, and the film is a polymer film which is flexible, the polymer film is at least one of a PTFE film, a PET film, a PP film, a PC film, and a PI film;
growing: growing conductive material in the through holes such that a one-dimensional columnar structure perpendicular to the substrate is formed in the through holes; wherein, a diameter of the one-dimensional columnar structure is 5 μm to 30 μm, a height of the one-dimensional columnar structure is 15 μm to 50 μm, and a height-to-diameter ratio of the one-dimensional columnar structure is 3:1 to 1:1; and
removing the film: removing the film and obtaining the intermediate structure.
2 . The preparation method for the intermediate structure according to claim 1 , wherein, conditions of the ion track etching process comprise: bombarding with heavy ions and irradiating at an irradiation power of 2000 KW to 10000 KW for 0.5 s to 200 s; and/or,
conditions of the ion track etching process comprise: an etching solution is an alkaline solution, and etching time is 5 min to 30 min.
3 . The preparation method for the intermediate structure according to claim 1 , wherein a diameter of the through holes is 10 nm to 50 μm, and/or,
an areal density of the through holes is 10 5 holes/cm 2 to 10 8 holes/cm 2 , and/or
a thickness of the film is 2 μm to 50 μm, and/or
a length-to-diameter ratio of the thickness of the film to the hole diameter of the through holes is 1:3 to 3:1.
4 . The preparation method for the intermediate structure according to claim 3 , wherein the diameter of the through holes is 5 μm to 30 μm, and/or,
an areal density of the through holes is 400000 holes/cm 2 to 2000000 holes/cm 2 , and/or
the thickness of the film is 15 μm to 50 μm, and/or
the length-to-diameter ratio of the thickness of the film to the hole diameter of the through holes is 1:1 to 3:1.
5 . The preparation method for the intermediate structure according to claim 1 , wherein, in the step of growing, a method of growing the conductive material in the through holes is one of physical vapor deposition, electroplating, chemical plating and chemical vapor deposition; and/or,
in the step of removing the film, a method of removing the film employs one of mechanical stripping, chemical etching or vacuum sintering.
6 . The preparation method for the intermediate structure according to claim 1 , wherein the one-dimensional columnar structure comprises a plurality of regularly distributed columns, and a spacing between adjacent columns is 5 μm to 20 μm; or, the one-dimensional columnar structure comprises a plurality of irregularly distributed columns.
7 . The preparation method for the intermediate structure according to claim 1 , wherein the substrate is at least one of a copper foil substrate, a nickel foil substrate, and a stainless steel substrate;
the conductive material is at least one of copper, nickel or carbon.
8 . A preparation method for a lithium secondary battery electrode, wherein the preparation method for the lithium secondary battery electrode comprises steps of:
coating an outer surface of the one-dimensional columnar structure of the intermediate structure prepared by the preparation method according to claim 1 with electrode active material and forming an active material layer; and
coating a protective layer on an outer surface of the active material layer and obtaining the lithium secondary battery electrode.
9 . The preparation method for the lithium secondary battery electrode according to claim 8 , wherein the electrode active material is at least one of silicon, germanium, and tin; and/or,
material of the protective layer is carbon or metal oxide; and/or,
a method of coating the electrode active material comprises chemical vapor deposition, physical vapor deposition or electroplating; and/or,
a method of coating the protective layer comprises hydrothermal, physical vapor deposition or chemical vapor deposition.