KR-102961536-B1 - Low-resistance multi-layered Fe-Ni alloy current collector and secondary battery comprising the same

KR102961536B1KR 102961536 B1KR102961536 B1KR 102961536B1KR-102961536-B1

Abstract

The present invention relates to a current collector having low resistance and high strength characteristics while improving corrosion resistance when used as a current collector for a secondary battery to which a lithium-ion or lithium-metal anode or a sulfide-based solid electrolyte is applied, by forming an Fe-Ni alloy on at least one surface of a core part made of copper foil (Cu foil).

Inventors

정관호
김기수
유신
심영섭
양진호

Assignees

주식회사 프렘투

Dates

Publication Date: 20260507
Application Date: 20231114

Claims (14)

As the battery's current collector, Copper foil and, It includes an Fe-Ni alloy layer containing iron (Fe) and nickel (Ni) formed on both sides of the copper foil (Cu foil), and A cathode characteristic material layer containing titanium (Ti) is formed on one side of the above Fe-Ni alloy layer, and The above current collector has a resistivity value of 5× 10⁻⁸ Ωm or less, and Low-resistance multilayer Fe-Ni alloy current collector for lithium metal batteries or sulfide-based all-solid-state batteries.
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In Article 1, A low-resistance multilayer Fe-Ni alloy current collector having a thickness of 4 to 20 μm.
In Article 1 or Article 4, A low-resistance multilayer Fe-Ni alloy current collector having a copper foil (Cu foil) thickness of 3 to 14 μm.
In Article 1 or Article 4, A low-resistance multilayer Fe-Ni alloy current collector having a combined thickness of 1 to 6 μm of Fe-Ni alloy layers formed on both sides of the copper foil (Cu foil).
In Article 1 or Article 4, The above Fe-Ni alloy layer is a low-resistance multilayer Fe-Ni alloy current collector composed of 10 to 90 weight percent nickel (Ni), the remainder being iron (Fe) and unavoidable impurities.
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In Article 1, A low-resistance multilayer Fe-Ni alloy current collector having a cathodic characteristic material layer thickness of 10 nm to 1 µm.
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In Article 1 or Article 4, The average grain size of the above Fe-Ni alloy layer is 15 nm or less (excluding 0 nm), and A low-resistance multilayer Fe-Ni alloy current collector having a tensile strength of 600 MPa or more and an elongation of 3% or more.
A cathode comprising a current collector described in claim 1 or 4 and a cathode active material layer formed on said current collector, and A positive electrode disposed opposite to the above-mentioned negative electrode and comprising a positive plate and a positive active material layer formed on the positive plate, and A secondary battery comprising an electrolyte disposed between the above-mentioned negative electrode and the above-mentioned positive electrode to provide an environment in which lithium ions can move.
In Article 12, A secondary battery comprising a separator disposed between the above-mentioned negative electrode and the above-mentioned positive electrode.
In Article 12, The above electrolyte is a secondary battery comprising a solid electrolyte.

Description

Low-resistance multi-layered Fe-Ni alloy current collector and secondary battery comprising the same The present invention relates to an Fe-Ni alloy current collector having a low-resistance multilayer structure and a secondary battery including the same. Lithium-ion batteries are widely commercialized due to their superior energy density and power output characteristics among various types of rechargeable batteries. Furthermore, as demand for electric vehicles and large-capacity power storage devices increases, there is a need for the development of high-energy batteries to meet these needs. In response to this, technology for applying lithium metal anodes to secondary batteries is being actively developed as a method to achieve high energy densities of over 400 Wh/kg. However, there have been recent reports that when lithium metal is applied to the anode, corrosion occurs in the copper foil used as the anode current collector, leading to a decrease in battery life. Meanwhile, carbonate-based organic solvents included in the liquid electrolytes currently widely used in lithium-ion batteries have problems such as low thermal stability and very high flammability. To address this, all-solid-state battery technology using solid electrolytes is being actively researched; however, in sulfide-based all-solid-state batteries, which are the most actively researched and developed, a problem is emerging in which sulfide-based solid electrolytes corrode the copper foil current collector. In secondary batteries, the current collector acts as a connecting medium to supply electrons or holes provided from an external wire to the electrode active material, or conversely, as a carrier that collects electrons or holes generated as a result of the electrode reaction and flows them to the external wire. In addition, the current collector functions as an important support in realizing the shape of the actual electrode plate. Furthermore, it is important that the metal constituting the current collector does not oxidize in the low potential region for the negative electrode current collector and in the high potential region for the positive electrode current collector. Generally, considering electrical conductivity, electrochemical stability, and suitability for the electrode plate manufacturing process, copper (Cu) is used for the negative electrode and aluminum (Al) or platinum (Pt) is used for the positive electrode, and active material particles are coated onto it and then dried to manufacture the electrode. However, as mentioned above, copper foil (Cu foil) has the critical problem of corrosion in lithium metal batteries and sulfide-based all-solid-state batteries, and since aluminum (Al) cannot be used as a negative electrode, it is impossible to utilize aluminum alone as a current collector possessing both negative and positive electrode characteristics. Furthermore, platinum (Pt) is excessively expensive, which increases battery costs, thus presenting limitations in terms of low economic efficiency for battery application and mass production. FIG. 1 illustrates, according to one embodiment of the present invention, an exemplary configuration of a multilayer current collector having a copper foil (Cu foil) in the core portion of the current collector and alloy layers containing iron (Fe) and nickel (Ni) laminated on both sides of the copper foil (Cu foil). FIG. 2 illustrates, according to one embodiment of the present invention, an exemplary configuration of a multilayer current collector in which a material layer having negative properties is additionally laminated on one surface of the current collector of FIG. 1. FIG. 3 illustrates, in accordance with one embodiment of the present invention, the structure of a secondary battery with the multilayer current collector of FIG. 1 applied. FIG. 4 illustrates, according to one embodiment of the present invention, an exemplary configuration of a secondary battery in which a negative electrode active material is formed on a material layer having negative electrode characteristics formed on one surface of a multilayer current collector of FIG. 2. FIG. 5 is a schematic diagram of a process and apparatus for manufacturing a multilayer current collector according to one embodiment of the present invention. Embodiments of the present invention are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. In addition, to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals. Throughout this specification, when a part is described as being "connected" to another part, this includes not only cases where they are "directly connected," but also cases where the