KR-102963581-B1 - Lithium Secondary Battery And All-solid-state Secondary Battery Having Low Humidity Oxide Coating Layer, Manufacturing Method of Lithium Secondary Battery Having Low Humidity Oxide Coating Layer

Abstract

The present invention discloses a lithium secondary battery having a low-humidity oxidation coating layer, wherein the performance and lifespan of the cell are improved by a LiOH and Li₂O coating layer formed on the surface of the lithium metal negative electrode, a lithium secondary battery having a lithium secondary battery having a low-humidity oxidation coating layer, and a method for manufacturing a lithium secondary battery having a low-humidity oxidation coating layer. The method for manufacturing a lithium secondary battery having a low-humidity oxide coating layer according to the present invention comprises: a first step (S10) of preparing a lithium negative electrode by cutting a lithium foil; a second step (S20) of exposing the lithium metal negative electrode to air at a temperature of 20°C to 25°C and a humidity of 15% to 25%; and a third step (S30) of depositing an amorphous metal alloy to a thickness of 10 to 15 μm by sputtering on the surface of the lithium metal negative electrode of the second step (S20).

Inventors

• 김석준
• 구동은
• 최정호

Assignees

• 한국기술교육대학교 산학협력단

Dates

Publication Date

20260512

Application Date

20240116

Claims (10)

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7. A method for manufacturing a lithium secondary battery having a low-humidity oxide coating layer, A first step of preparing a lithium metal negative electrode by cutting a lithium foil; and A method for manufacturing a lithium secondary battery having a low-humidity oxide coating layer, comprising: a second step of exposing the lithium metal negative electrode to air at a temperature of 20°C to 25°C and a humidity of 15% to 25% to form a low-humidity oxide coating layer.
8. A method for manufacturing a lithium secondary battery having a low-humidity oxide coating layer, Step 1: preparing a lithium metal negative electrode by cutting a lithium foil; A second step of forming a low-humidity oxide coating layer by exposing the lithium metal negative electrode to air at a temperature of 20°C to 25°C and a humidity of 15% to 25%; and A method for manufacturing a lithium secondary battery having a low-humidity oxide coating layer, comprising: a third step of forming an amorphous metal alloy layer by sputtering on one surface of the low-humidity oxide coating layer of the second step to a thickness of 10 nm to 15 nm.
9. In claim 8, A method for manufacturing a lithium secondary battery having a low-humidity oxide coating layer, characterized in that the time for exposing the lithium metal negative electrode to air in the second step is 10 minutes to 120 minutes.
10. A method for manufacturing a lithium secondary battery having a low-humidity oxide coating layer, Step 1: preparing a lithium metal negative electrode by cutting a lithium foil; A second step of forming a low-humidity oxide coating layer by sputtering and depositing a target mixed powder composed of LiOH and Li₂O on the surface of the lithium metal negative electrode in a vacuum to a thickness of 5 nm to 500 nm; and A method for manufacturing a lithium secondary battery having a low-humidity oxide coating layer, comprising: a third step of depositing an amorphous metal alloy to a thickness of 10 nm to 15 nm by sputtering on the surface of the lithium metal negative electrode of the second step above.

Description

Lithium Secondary Battery and All-solid-state Secondary Battery Having Low Humidity Oxide Coating Layer, Manufacturing Method of Lithium Secondary Battery Having Low Humidity Oxide Coating Layer The present invention relates to a lithium secondary battery having a low-humidity oxide coating layer, an all-solid-state secondary battery, and a method for manufacturing a lithium secondary battery having a low-humidity oxide coating layer. More specifically, the invention relates to a lithium secondary battery having a low-humidity oxide coating layer comprising a lithium metal negative electrode oxidized at low humidity, an all-solid-state secondary battery, and a method for manufacturing a lithium secondary battery having a low-humidity oxide coating layer. A lithium secondary battery is a battery that generates electrical energy through changes in chemical potential when lithium ions intercalate or deintercalate at the positive and negative electrodes. The operating voltage and energy density of a lithium secondary battery can vary depending on the electrode active material, the type of electrolyte, and the loading amount of the electrode composite layer. Lithium cobalt composite oxides and lithium-containing manganese composite oxides are used as positive electrode active materials, while lithium metal, carbon-based materials, and silicon are used as negative electrode active materials. When lithium metal is used as the anode, lithium dendrites form on the surface of the lithium metal during the charging and discharging process. If lithium dendrites grow and penetrate the separator, micro-short circuits occur, which not only shortens the lifespan of the lithium secondary battery but also poses a critical safety risk. Therefore, research is needed to suppress the growth of these lithium dendrites to improve cell performance and lifespan. FIG. 1 is a flowchart of a method for manufacturing a lithium secondary battery having a low humidity oxide coating layer according to a third embodiment of the present invention. FIG. 2 is a flowchart of a method for manufacturing a lithium secondary battery having a low humidity oxide coating layer according to a fourth embodiment of the present invention. Figure 3(a) shows that when bare lithium is used, the current is concentrated and the plated lithium grows in a dendrite shape, and Figure 3(b) shows that a thin layer of LiOH and Li₂O on the lithium surface prevents the lithium from growing in a dendrite shape, thereby inducing the lithium to grow evenly. Figure 4(a) shows that as oxidation proceeds , Li₂CO₃ is formed on the surface, and Li₂CO₃ hinders the plating of lithium, while Figure 4(b) shows that 12ZrMG is deposited on the surface to remove the thin layer of Li₂CO₃ , allowing lithium to be plated evenly. Figure 5 shows the relationship between the number of cycles, discharge capacity, and Coulomb efficiency of a full cell during low humidity oxidation. Figure 6(a) shows the relationship between the capacity and voltage of a full cell during low humidity oxidation after 1 cycle, and Figure 6(b) shows the relationship between the capacity and voltage of a full cell during low humidity oxidation after 5 cycles. Figure 7 shows the relationship between the number of cycles and the discharge capacity of a full cell during high humidity oxidation. Figure 8 shows the relationship of voltage with respect to time (overpotential) of a full cell during low humidity oxidation. Figure 9(a) shows the XPS at a depth of 0 nm on the electrode surface during low humidity oxidation, Figure 9(b) shows the XPS at a depth of 20 nm on the electrode surface during low humidity oxidation, and Figure 9(c) shows the XPS at a depth of 150 nm on the electrode surface during low humidity oxidation. Figure 10 shows the number of oxygen (O) and carbon (C) per 100 lithium using the atomic percentage of each element. The present invention is susceptible to various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the invention to specific embodiments, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention. Similar reference numerals have been used for similar components in the description of each drawing. Terms such as first, second, A, B, etc., may be used to describe various components, but said components shall not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component. The term "and/or" includes a combination of a plurality of related described items or any of a plurality of related described item