KR20220038196A - Electroless nickel-boron plating solution having tert-butyl amine borane for electrode terminal of lithium ion battery, method of electroless nickel-boron plating using the same, and electrode terminal of lithium ion battery having nickel-boron electroless plating layer using the same - Google Patents

Abstract

The present invention provides a nickel-boron electroless plating solution for plating an electrode terminal of a lithium ion battery including TBAB, which has excellent etch resistance and high temperature stability, and provides excellent plating properties. The nickel-boron electroless plating solution for plating the electrode terminal of the lithium ion battery according to one embodiment of the present invention comprises: a nickel metal salt providing nickel ions for plating; a reducing agent which reduces the nickel ions for plating and includes TBAB in a range of 0.01 to 0.05 M; a complexing agent for forming a complex with the nickel ions for plating; and a stabilizer for suppressing a reduction reaction of the nickel ions for plating.

Description

Nickel-boron electroless plating solution for electrode terminal plating of lithium ion batteries, including TBAB, nickel-boron electroless plating method using the same, and nickel-boron electroless plating layer manufactured using the same Electroless nickel-boron plating solution having tert-butyl amine borane for electrode terminal of lithium ion battery, method of electroless nickel-boron plating using the same, and electrode terminal of lithium ion battery having nickel-boron electroless plating layer using the same}

The present invention relates to electroless plating, and more particularly, a nickel-boron electroless plating solution for plating electrode terminals of a lithium ion battery containing tertiary butylamine borane, a nickel-boron electroless plating method using the same, and a method using the same It relates to an electrode terminal of a lithium ion battery having a nickel-boron electroless plating layer prepared by doing so.

Electroless plating is a method of forming a metal plating layer on an object to be plated by oxidation-reduction reaction of metal, and plating is possible regardless of the shape of the product. used in the field.

The surface plated using the electroless plating method is increasingly important in the parts and material industry, such as being used as a mounting surface or bonding interface for ultra-small devices with high density in various packaging fields. In recent years, high density and narrow pitch of internal circuits are required according to weight reduction, miniaturization, and high functionality of electronic products. is increasing

Among them, nickel plating is an important technology in the field of rechargeable battery components. A lead tab, which is an electrode terminal, electrically connects the inside of the battery and the outside of the battery, and separates an aluminum terminal for the positive electrode and nickel-plated copper for the negative electrode. In recent years, the demand for high-performance rechargeable batteries has increased. At the same time, the lead tab requires properties such as increased conductivity, corrosion resistance, and hydrofluoric acid resistance to increase high power density and durability. Nickel plating for the lead tab generally includes nickel-phosphorus (Ni-P) electrolytic plating or electroless plating. Recently, nickel-boron (Ni-B) plating has been proposed because it is difficult to manage a plating solution for nickel-phosphorus plating. However, scientific research on etching resistance such as corrosion resistance and hydrofluoric acid resistance for using a nickel-boron electroless plating layer for lead tabs of lithium ion batteries is insufficient.

The technical problem to be achieved by the technical idea of the present invention is a nickel-boron electroless plating solution for electrode terminal plating of lithium ion batteries, including tertiary butylamine borane, which has excellent etch resistance and high temperature stability, and provides excellent plating properties, To provide a nickel-boron electroless plating method using the same, and an electrode terminal of a lithium ion battery having a nickel-boron electroless plating layer manufactured using the same.

However, these tasks are exemplary, and the technical spirit of the present invention is not limited thereto.

Nickel-boron electroless plating solution for plating an electrode terminal of a lithium ion battery according to the technical idea of the present invention for achieving the above technical problem, a nickel metal salt providing nickel ions for plating; a reducing agent that reduces the nickel ions for plating and includes TBAB in the range of 0.01 M to 0.05 M; a complexing agent for forming a complex with the nickel ion for plating; and a stabilizer for suppressing the reduction reaction of nickel ions for plating.

In an embodiment of the present invention, the nickel-boron electroless plating solution for plating the electrode terminal of the lithium ion battery includes, as the nickel metal salt, nickel sulfate hexahydrate in the range of 0.05 M to 0.2 M; Citric acid in the range of 0.05 M to 0.2 M as the complexing agent; lead nitrate in the range of 1 ppm to 3 ppm as the stabilizer; and TBAB in the range of 0.01 M to 0.05 M as the reducing agent.

In one embodiment of the present invention, the nickel metal salt may include at least one of nickel sulfate, nickel chloride, nickel sulfamic acid, nickel nitrate, nickel oxide, and nickel carbonate.

In one embodiment of the present invention, the complexing agent is acetic acid, adipic acid, formic acid, propionic acid, butyric acid, valeric acid ), caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid ( lauric acid), tridecylic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid , arachidic acid, oxalic acid, malonic acid, tartaric acid, succinic acid, glutaric acid, pimelic acid, water suberic acid, azelaic acid, sebacic acid, ortho-phthalic acid, isophthalic acid, terephthalic acid, taleic acid ), fumaric acid, glutaconic acid, traumatic acid, and muconic acid, glycolic acid, lactic acid, citric acid , and may include at least one of mandelic acid.

In one embodiment of the present invention, the stabilizer is, of lead (Pb), tellenium (Te), selenium (Se), bismuth (Bi), tin (Sn), thallium (Tl), and molybdenum (Mo) It may include at least one.

In one embodiment of the present invention, the nickel-boron electroless plating solution for plating the electrode terminal of the lithium ion battery may further include at least one of a pH adjuster, an auxiliary additive, and a surfactant.

In one embodiment of the present invention, the nickel-boron electroless plating solution for plating the electrode terminal of the lithium ion battery may have a pH of 6 to pH 8.

Nickel-boron electroless plating method of an electrode terminal of a lithium ion battery according to the technical idea of the present invention for achieving the above technical problem, immersing a metal plating object in an etching solution; nickel strike electrolytic plating of the metal plating object; and forming a nickel-boron electroless plating layer by electroless plating the metal plating object using the nickel-boron electroless plating solution including the TBAB.

In an embodiment of the present invention, in the forming of the nickel-boron electroless plating layer, the nickel metal salt contains nickel sulfate hexahydrate in the range of 0.05 M to 0.2 M, and the complexing agent is in the range of 0.05 M to 0.2 M of citric acid, lead nitrate in the range of 1 ppm to 3 ppm as the stabilizer, and the TBAB in the range of 0.01 M to 0.05 M as the reducing agent. can

In one embodiment of the present invention, after performing the step of immersion in the etching solution, after performing the nickel strike electrolytic plating step, and after performing the step of forming the nickel-boron electroless plating layer, The method may further include cleaning the metal plating object using deionized water, respectively.

In an embodiment of the present invention, the step of immersing in the etching solution is performed for a time in the range of 10 seconds to 20 seconds at a temperature in the range of 20°C to 30°C using a sulfuric acid solution in the range of 5% to 10%. can do.

In one embodiment of the present invention, the nickel strike electrolytic plating step is, NiCl ₂ in the range of 40 g/L to 50 g/L, NiSO ₄ 6 (H ₂ O) in the range of 200 g/L to 300 g/L ), and using a nickel strike electrolytic plating solution comprising H ₃ BO ₃ in the range of 25 g/L to 30 g/L, a pH in the range of pH 4 to pH 5, a temperature in the range of 40° C. to 60° C., and 5 It can be carried out under process conditions in which a voltage in the range of V to 7 V is applied for an application time in the range of 10 seconds to 15 seconds.

In an embodiment of the present invention, the forming of the nickel-boron electroless plating layer may be performed under process conditions of a pH ranging from pH 6 to pH 8 and a temperature ranging from 50° C. to 70° C.

An electrode terminal of a lithium ion battery according to the technical idea of the present invention for achieving the above technical problem, a metal plating object; and a nickel-boron electroless plating layer formed on the surface of the metal plating object by electroless plating using a nickel-boron electroless plating solution containing TBAB in the range of 0.01 M to 0.05 M.

In an embodiment of the present invention, the nickel-boron electroless plating layer may include nickel in a range of 95 wt% to 99 wt% and boron in a range of 1 wt% to 5 wt%.

의 온도, pH 8에서 최적화되었다. 상기 최적화 도금액 조건들 하에서 형성된 니켈-보론 무전해 도금층은, 디메틸아민보란(DMAB)을 이용하여 형성한 니켈-보론 무전해 도금층에 비하여, 전해질 내에서의 우수한 식각 저항과 고온에서의 개선된 안정성을 나타내었다. 따라서, 상기 니켈-보론 무전해 도금층의 두드러진 특성들에 의하여, 상기 TBAB을 사용하는 제조 기술은 다른 니켈-보론 무전해 도금층들의 제조에 적용될 수 있다.A nickel-boron electroless plating layer was formed on a copper substrate by a direct electroless plating technique using a nickel-boron electroless plating solution including TBAB according to the technical concept of the present invention. In the case of using TBAB as a reducing agent, the effects of electroless plating conditions on the composition of the plating layer, the surface shape, the etch resistance in the electrolyte, and the high temperature stability were studied. The surface shape of the nickel-boron electroless plating layer was analyzed using a scanning electron microscope, and the chemical composition of the nickel-boron electroless plating layer was analyzed using an X-ray fluorescence spectrometer. According to the electrochemical analysis using the potentiometric polarization, 0.1 M nickel-boron electroless plating solution for nickel-boron plating had a composition of 0.03 M TBAB, 60

was optimized at a temperature of 8 The nickel-boron electroless plating layer formed under the optimized plating solution conditions exhibits superior etch resistance in the electrolyte and improved stability at high temperatures compared to the nickel-boron electroless plating layer formed using dimethylamine borane (DMAB). indicated. Therefore, by virtue of the outstanding properties of the nickel-boron electroless plating layer, the manufacturing technique using the TBAB can be applied to the manufacture of other nickel-boron electroless plating layers.

The above-described effects of the present invention have been described by way of example, and the scope of the present invention is not limited by these effects.

1 is a schematic diagram illustrating a plating apparatus using a nickel-boron electroless plating solution for an electrode terminal of a lithium ion battery according to an embodiment of the present invention.
2 is a flowchart illustrating a nickel-boron electroless plating method of an electrode terminal of a lithium ion battery according to an embodiment of the present invention.
3 is a schematic diagram illustrating a nickel-boron electroless plating method of an electrode terminal of a lithium ion battery according to an embodiment of the present invention.
4 is a graph showing the polarization characteristics according to the composition of the TBAB for the nickel-boron electroless plating solution for the electrode terminal of a lithium ion battery according to an embodiment of the present invention.
5 is a graph showing a plating rate according to a composition of TBAB for a nickel-boron electroless plating solution for an electrode terminal of a lithium ion battery according to an embodiment of the present invention.
6 is a graph showing polarization characteristics according to pH of a nickel-boron electroless plating solution for an electrode terminal of a lithium ion battery according to an embodiment of the present invention.
7 is a graph showing a plating rate according to pH of a nickel-boron electroless plating solution for an electrode terminal of a lithium ion battery according to an embodiment of the present invention.
8 is a graph showing the thickness change before and after immersing the nickel-boron electroless plating layer formed using the nickel-boron electroless plating method of the electrode terminal of the lithium ion battery according to an embodiment of the present invention in the electrolyte.
9 is an optical micrograph showing the surface state before and after immersing the nickel-boron electroless plating layer formed using the nickel-boron electroless plating method of the electrode terminal of the lithium ion battery according to an embodiment of the present invention in the electrolyte; admit.
10 is a scanning electron microscope showing the surface state of the nickel-boron electroless plating layer formed by using the nickel-boron electroless plating method of the electrode terminal of the lithium ion battery according to an embodiment of the present invention before and after immersion in the electrolyte; they are photos

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments of the present invention are provided to more completely explain the technical idea of the present invention to those of ordinary skill in the art, and the following examples may be modified in various other forms, The scope of the technical idea is not limited to the following examples. Rather, these embodiments are provided so as to more fully and complete the present disclosure, and to fully convey the technical spirit of the present invention to those skilled in the art. In this specification, the same reference numerals refer to the same elements throughout. Furthermore, various elements and regions in the drawings are schematically drawn. Accordingly, the technical spirit of the present invention is not limited by the relative size or spacing drawn in the accompanying drawings.

After the concept of nickel electroless plating was presented by Brenner and Riddell in 1946, the electroless plating technique has been extensively studied because it has advantages of providing excellent adhesion and uniform thickness. Nickel electroless plating can be applied not only to metallic materials, but also to non-conductive surfaces such as plastics and ceramics. Nickel electroless plating techniques can be classified according to reducing agents in the plating solution. For example, when using a sodium hypophosphite (NaH ₂ PO ₂ ) reducing agent, nickel-phosphorus (Ni-P), sodium borohydride (NaBH ₄ ) when using a reducing agent, nickel = boron (Ni-B), dimethylamine borane (DMAB, C ₂ H ₇ BN) Pure nickel (N)i when a reducing agent is used, hydrazine (NH ₂ NH ₂ ) Nickel when a reducing agent is used classified as alloys.

In particular, among them, the nickel-phosphorus electroless plating method with sodium hypophosphite has achieved commercial success because of its low cost, excellent workability, and excellent physical properties of the plating layer. On the other hand, the nickel-boron electroless plating method was relatively limited because, compared to the nickel-phosphorus electroless plating using hypophosphite, the nickel-boron electroless plating method has high cost and high impurity sensitivity. Because. However, compared to the nickel-phosphorus electroless plating method, the nickel-boron electroless plating method may form a plating layer having high hardness, a low coefficient of friction, and excellent etching resistance.

The nickel-boron electroless plating method generally uses a Watts bath containing various sulfamates and boron-containing reducing agents. The boron-containing reducing agents include, for example, sodium borohydride, dimethylamineborane, trimethylamineborane (TMAB), or sodium decahydrodecarborate (Na ₂ B ₁₀ H ₁₀ ). By controlling effective parameters such as current density, temperature, agitation, and pH during electroplating, the co-deposited boron content can even out the nickel reduction rate. The performance of these co-deposited boron is strongly affected by the type of boron source.

For example, the sodium borohydride can provide up to 8 electrons for metal reduction, and as a result, provides high reduction efficiency and cost effectiveness. However, since borohydride ions are easily hydrolyzed in an acidic or neutral solution, they combine with nickel ions present in the plating solution to spontaneously form nickel boride. As a result, the composition and structure of the plating layer can be easily changed.

When the dimethylamine borane is used as a reducing agent, the stability of the plating solution can be improved in a wide pH range, used at a relatively low temperature compared to the sodium borohydride, and the plating solution composition can be maintained uniformly. In particular, since the electroless plating solutions using dimethylamine borane can be used at a relatively low temperature, they can be generally used for electroless plating for electronic components. However, in the case of using dimethylamine borane, there is a limitation in that the etching resistance is low.

According to the technical idea of the present invention, a nickel-boron (Ni-B) electroless plating method using tert-butyl amine borane (TBAB) as a reducing agent is proposed. Effect on the surface properties and electroless conditions of the nickel-boron electroless plating layer when TBAB was used as the reducing agent compared to the surfaces of the nickel-boron electroless plating layer formed using dimethylamine borane as the reducing agent , and the effect of improving the electrolyte resistance (ie, etching resistance) of lead tab materials of rechargeable batteries is analyzed.

Hereinafter, a nickel-boron electroless plating solution for plating an electrode terminal of a lithium ion battery according to the technical spirit of the present invention will be briefly referred to as a nickel-boron electroless plating solution.

1 is a schematic diagram illustrating a plating apparatus 10 using a nickel-boron electroless plating solution for an electrode terminal of a lithium ion battery according to an embodiment of the present invention.

Referring to FIG. 1 , the plating apparatus 10 accommodates a nickel-boron electroless plating solution 30 including TBAB in a plating bath 20 , and a metal plating object 40 in the nickel-boron electroless plating solution 30 . is immersed to form a plating layer 50 on the metal plating object 40 . In addition, the case of using a metal plating solution other than the nickel-boron electroless plating solution 30 is also included in the technical concept of the present invention.

The nickel-boron electroless plating solution 30 includes a solvent, and a nickel metal salt, a reducing agent, a complexing agent, and a stabilizer dissolved in the solvent. In addition, the nickel-boron electroless plating solution 30 may further include a pH adjusting agent that adjusts the pH to, for example, 6 to 8 range. In addition, the nickel-boron electroless plating solution 30 may further include an auxiliary additive composed of an organic compound or an inorganic compound to control the plating speed and improve gloss properties. In addition, the nickel-boron electroless plating solution 30 may further include a surfactant for improving interfacial properties between the matrix layer and the plating layer and preventing pit formation.

The metal plating object 40 may include a metal material or a polymer material. The metal plating object 40 may include, for example, copper or iron. The metal plating object 40 may be an electrode terminal of a lithium ion battery after the plating layer is formed.

Accordingly, the electrode terminal of the lithium ion battery according to the technical idea of the present invention, a metal plating object; and a nickel-boron electroless plating layer formed on the surface of the metal plating object by electroless plating using a nickel-boron electroless plating solution containing TBAB in the range of 0.01 M to 0.05 M.

Hereinafter, components constituting the nickel-boron electroless plating solution 30 will be described in detail.

The solvent may constitute most of the nickel-boron electroless plating solution 30 in which the metal plating object 40 is immersed. The solvent may include a material that dissolves the nickel metal salt, the reducing agent, the complexing agent, and the stabilizer. The solvent may be, for example, water. However, this is exemplary and the technical spirit of the present invention is not limited thereto.

The nickel metal salt may be dissolved in the solvent. The nickel metal salt may provide nickel ions for plating to the metal plating object 40 , and the nickel ions for plating may form the plating layer 50 on the metal plating object 40 . The nickel metal salt may include a metal, for example, may include nickel (Ni). Accordingly, the nickel ions for plating may include nickel (Ni) ions, and the nickel ions may be, for example, divalent ions. The nickel metal salt may include, for example, nickel salt hydrate, for example, may include at least one of nickel sulfate, nickel chloride, nickel sulfamic acid, nickel nitrate, nickel oxide, and nickel carbonate. For example, the nickel sulfate may be obtained by dissolving nickel, nickel oxide, or nickel carbonate in sulfuric acid and evaporating it at room temperature, thereby precipitating it as green needle-shaped crystals (orthorhombic). The nickel sulfate may include, for example, nickel sulfate hexahydrate.

The reducing agent may be dissolved in the solvent. The reducing agent may reduce the nickel ions for plating. The reducing agent may reduce the nickel ion, for example. The reducing agent may include TBAB. The reducing agent, for example, may have a composition in the range of 0.01 M to 0.1 M, for example, may have a composition in the range of 0.01 M to 0.05 M.

The complexing agent may be dissolved in the solvent. The complexing agent may form a complex with the nickel ion for plating. For example, the complexing agent may chemically combine with the nickel ion to form a nickel complex. The complexing agent controls the plating speed, prevents the nickel-boron electroless plating solution 30 from being decomposed spontaneously, and controls the plating reaction so that the reduction reaction of nickel occurs smoothly on the surface of the metal plating object 40 . can The complexing agent can control the total amount of nickel ions participating in the reduction reaction with organic acids or salts thereof, and prevents the nickel ions from binding to phosphorus and precipitating as nickel phosphate, thus nickel-boron electroless plating solution (30) It can perform a function to maintain stability during this plating operation. In addition, the complexing agent may prevent the pH of the nickel-boron electroless plating solution 30 from rapidly changing by reducing the rapid generation of hydrogen ions by the reduction reaction. The complexing agent is, for example, carboxylic acid and its derivatives, for example, acetic acid, adipic acid, formic acid, propionic acid, butyric acid, valeric acid valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, Lauric acid, tridecylic acid, myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid (stearic acid), arachidic acid, oxalic acid, malonic acid, tartaric acid, succinic acid, glutaric acid, pimelic acid acid), suberic acid, azelaic acid, sebacic acid, ortho-phthalic acid, isophthalic acid, terephthalic acid, maleic acid It may include at least one of taleic acid, fumaric acid, glutaconic acid, traumatic acid, and muconic acid. In addition, the complexing agent, alpha-hydroxyl acid and its derivatives, for example, glycolic acid (glycolic acid), lactic acid (lactic acid), citric acid (citric acid), and mandelic acid (mandelic acid) at least any one may include

The stabilizer may be dissolved in the solvent. The stabilizer may suppress the reduction reaction of the nickel ions for plating. In particular, the stabilizer may perform a function of stabilizing the nickel-boron electroless plating solution 30 by suppressing a reduction reaction in an area other than the area where the plating layer 50 of the metal plating object 40 is to be formed. . The stabilizer may include a metal element. The stabilizer may include, for example, at least one of lead (Pb), telenium (Te), selenium (Se), bismuth (Bi), tin (Sn), thallium (Tl), and molybdenum (Mo). can The stabilizer may include, for example, lead nitrate. In order to prevent the stabilizer from being liberated in the nickel-boron electroless plating solution 30 and acting as an impurity, the stabilizer is previously dissolved in a strong acid solution such as hydrochloric acid or nitric acid or a strong alkali solution such as caustic soda solution to form nickel-boron. It can be added to the electroless plating solution (30).

The pH adjusting agent may be dissolved in the solvent. Since the plating layer 50 formed on the metal plating object 40 is affected by the plating speed and the thickness of the plating layer by the pH of the nickel-boron electroless plating solution 30 , the pH of the nickel-boron electroless plating solution 30 . It is preferable to add a substance that can maintain and control the constant. Accordingly, the pH adjusting agent may be added to the nickel-boron electroless plating solution 30 as a material performing this function. The pH adjusting agent may adjust the pH of the nickel-boron electroless plating solution 30 . The pH adjusting agent may include an acidic substance such as sulfuric acid, hydrochloric acid, nitric acid, or the like, or a basic substance such as aqueous ammonia, sodium hydroxide, or potassium hydroxide. The amount of the pH adjusting agent added to the nickel-boron electroless plating solution 30 to maintain the pH of the nickel-boron electroless plating solution 30, for example, in the range of 5 to 9, for example, in the range of 6 to 8, is added to the nickel-boron electroless plating solution. can be adjusted.

2 is a flowchart illustrating a nickel-boron electroless plating method (S100) for an electrode terminal of a lithium ion battery according to an embodiment of the present invention.

3 is a schematic diagram illustrating a nickel-boron electroless plating method (S100) for an electrode terminal of a lithium ion battery according to an embodiment of the present invention.

2 and 3 , the electroless plating method ( S100 ) includes immersing an object to be plated in an etching solution ( S110 ); first cleaning the object to be plated (S120); performing nickel strike electrolytic plating on the object to be plated (S130); Secondary cleaning of the object to be plated (S140); forming a nickel-boron electroless plating layer by electroless plating the object to be plated using a nickel-boron electroless plating solution containing TBAB (S150); and a third cleaning step (S160) of the object to be plated.

The nickel-boron electroless plating method of the electrode terminal of a lithium ion battery according to the technical spirit of the present invention includes the steps of preparing a nickel-boron electroless plating solution including the above-described TBAB; and electrolessly plating the object to be plated using the nickel-boron electroless plating solution to form a nickel-boron electroless plating layer.

The nickel-boron electroless plating layer formed on the electrode terminal of the lithium ion battery may be plated on the surface of the object to be plated by the nickel-boron electroless plating solution for the electrode terminal of the lithium ion battery including the TBAB. The nickel-boron electroless plating layer may include nickel in a range of 95 wt% to 99 wt% and boron in a range of 1 wt% to 5 wt%.

Experimental example

Hereinafter, preferred experimental examples are presented to help the understanding of the present invention. However, the following experimental examples are only for helping understanding of the present invention, and the present invention is not limited by the following experimental examples.

As an object to be plated, a copper substrate having a width x length x thickness of 10 mm x 10 mm x 1 mm was prepared. Such copper substrates are commercially available.

The immersion in the etching solution (S110) may be performed using an acidic solution such as hydrochloric acid, nitric acid, sulfuric acid, or hydrofluoric acid. For example, the step (S110) may be performed using a sulfuric acid solution in the range of 5% to 10% at a temperature in the range of 20°C to 30°C for a time in the range of 10 seconds to 20 seconds. By performing the step (S110), the surface sensitivity of the object to be plated may be increased and activated.

In this experimental example, the step (S110) was performed for 12 seconds at a temperature of 25 ℃ using a 7% sulfuric acid (H ₂ SO ₄ ) solution.

Then, the first cleaning of the metal plating object (S120) is performed. The first washing may be performed using deionized water, and may be performed for a time ranging from 5 seconds to 30 seconds.

In this experimental example, the step (S120) was performed by immersion in deionized water for 10 seconds.

Next, a step (S130) of electroplating the metal plated object by nickel strike is performed. The step (S130) is a pre-treatment for nickel-boron electroless plating on the metal plating object, and a Wood's nickel strike is performed. The nickel strike electroplating solution is in the range of 40 g/L to 50 g/L of NiCl ₂ , NiSO ₄ 6 (H ₂ O) in the range of 200 g/L to 300 g/L, and 25 g/L to 30 g/L. of H ₃ BO ₃ may be included. In addition, in the step (S130), a pH in the range of pH 4 to pH 5, a temperature in the range of 40° C. to 60° C., and a voltage in the range of 5 V to 7 V are applied for an application time in the range of 10 seconds to 15 seconds. It can be carried out under process conditions.

In this experimental example, in the step (S130), 45 g/L NiCl ₂ , 240 g/L NiSO ₄ 6 (H ₂ O), and 30 g/LH ₃ BO ₃ A nickel strike electrolytic plating solution was used, pH It was carried out under process conditions of applying a temperature of 4.5, 50 °C, and a uniform voltage of 6 V for 12 seconds.

Then, a second cleaning step (S140) of the metal plating object is performed. The second washing may be performed using deionized water, and may be performed for a time ranging from 5 seconds to 30 seconds.

In this experimental example, the step (S140) was performed by immersion in deionized water for 10 seconds.

Thereafter, the metal plating object is electroless-plated using a nickel-boron electroless plating solution containing TBAB to form a nickel-boron electroless plating layer (S150). The step (S150) may be performed using the nickel-boron electroless plating solution 30 as described above, and the nickel-boron electroless plating solution 30 is a nickel metal salt, a reducing agent including TBAB, a complexing agent, and stabilizers. The step (S150) is, for example, comprising nickel sulfate hexahydrate as the nickel metal salt, citric acid as the complexing agent, lead nitrate as the stabilizer, and TBAB as the reducing agent. It can be carried out using a nickel-boron electroless plating solution. In addition, the step (S150) includes, for example, nickel sulfate hexahydrate in the range of 0.05 M to 0.2 M as the nickel metal salt, and citric acid in the range of 0.05 M to 0.2 M as the complexing agent, and as the stabilizer It may be carried out using the nickel-boron electroless plating solution comprising lead nitrate in the range of 1 ppm to 3 ppm, and the TBAB in the range of 0.01 M to 0.05 M as the reducing agent. The step (S150) may be performed under process conditions of a pH in the range of pH 6 to pH 8 and a temperature in the range of 50°C to 70°C.

In this experimental example, in the step (S140), the nickel metal salt as a nickel source is 0.1 M nickel sulfate hexahydrate (nickel sulfate hexahydrate, NiSO ₄ 6 (H ₂ O), >98%, Alfa Aesar), as a complexing agent 0.1 M citric acid (C ₆ H ₈ O ₇ , >99%, Aldrich), 2 ppm lead nitrate (Pb(NO ₃ ) ₂ , >99%, Aldrich) as a stabilizer, and TBAB ( (CH ₃ ) ₃ CNH ₂ BH ₃ , >97%, Alfa Aesar) The nickel-boron electroless plating solution was used. In addition, the nickel-boron electroless plating solution was prepared by changing the composition of the reducing agent to 0.01 M, 0.03 M, 0.05 M, 0.07 M, and 0.1 M. In addition, a specimen was prepared by changing the pH to 6 to 8. The temperature of the nickel-boron electroless plating solution was maintained at 60°C.

Then, a third cleaning step (S160) of the metal plating object is performed. The third washing may be performed using deionized water, and may be performed for a time ranging from 5 seconds to 30 seconds.

In this experimental example, the step (S160) was performed by immersion in deionized water for 10 seconds.

According to the method described above, a nickel-boron electroless plating specimen formed using TBAB as a reducing agent was prepared according to the technical idea of the present invention.

As a comparative example, a nickel-boron electroless plating specimen formed using the same conditions as described above, but as a reducing agent, dimethylamineborane ((CH ₃ ) ₂ NH BH ₃ , >97%, Alfa Aesar) was prepared. .

Electroless Plating Characterization

The surface shape and microstructure of the nickel-boron electroless plating specimens were analyzed using an optical microscope and a scanning electron microscope (SEM, Tescan Mira LM). In addition, the composition and thickness of the nickel-boron electroless plating specimen were analyzed using X-ray fluorescence spectroscopy (XRF, Rigaku ZSX Primus).

A three-electrode system was used for the electrochemical measurement of the nickel-boron electroless plating specimen, and a saturated caramel electrode (SCE) as a reference electrode, a graphite electrode as a counter electrode, and a nickel strike electrode as a working electrode were used.

Potential polarization of the nickel-boron electroless plating specimen was performed using an electrochemical measuring instrument (ZIVE SP2 potentiostat/galvanostat). The nickel-boron electroless plating specimen had a working surface of 1 cm ² , and was performed under various nickel-boron electroless plating solution conditions at a potential scan rate of 2 mV s ⁻¹ .

Etching resistance in the electrolyte of the nickel-boron electroless plating specimen was obtained by adding 1 M LiPF ₆ to a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a 1:1 volume ratio. It was measured by immersing the nickel-boron electroless plating specimen in the containing electrolyte at 80° C. for 24 hours.

The high temperature stability of the nickel-boron electroless plating specimen was measured after sintering at 450° C. for 24 hours.

Results and analysis

Electroless plating is an autocatalytic electrochemical reaction, and the local cathodic polarization curve of nickel ions and the local anode polarization curve of tert-butyl amine borane (TBAB) may occur at potentials overlapped by the hybrid potential theory. can

4 is a graph showing polarization characteristics according to a composition of TBAB for a nickel-boron electroless plating solution according to an embodiment of the present invention.

5 is a graph illustrating a plating rate according to a composition of TBAB for a nickel-boron electroless plating solution according to an embodiment of the present invention.

4 and 5 , the nickel-boron electroless plating solution had process conditions of a nickel ion composition of 0.1 M, a temperature of 60° C., and a pH of pH 6. The plating rate was calculated by a gravimetric method. Characteristics are shown immediately after nickel strike plating and when the composition of the TBAB is changed.

Referring to FIG. 4 , the change in hybrid potential according to the change in the composition of the TBAB was not remarkable. Specifically, as the current density of the anode polarization increased, the hybrid potential was negative in the composition of TBAB of 0.03 M, and the absolute value was the largest. As a negative number, the absolute value did not increase but decreased slightly. In addition, as the composition of the TBAB increased, the current density decreased.

Referring to FIG. 5 , when the composition of TBAB is increased to 0.03 M in a nickel ion plating solution of 0.1 M, the oxidation/reduction reaction becomes an equilibrium state, and the plating rate exhibits a maximum value.

Specifically, it can be seen that the plating rate increases when the TBAB is 0.01 to 0.06 mol per 1 liter, and more preferably, when the TBAB is 0.02 to 0.05 mol, the plating rate increases the most.

On the other hand, when the TBAB exceeds 0.07 mol, it can be seen that the effect of increasing the plating rate is insignificant. This is analyzed because the composition of nickel ions in the nickel-boron plating solution that can be precipitated in the reduction reaction is lower than that of TBAB, and thus it is difficult to occur in the redox reaction in an equilibrium state. Therefore, it can be seen that the plating speed does not have a proportional effect according to the composition of the reducing agent.

6 is a graph showing polarization characteristics according to pH of a nickel-boron electroless plating solution according to an embodiment of the present invention.

7 is a graph showing a plating rate according to pH for a nickel-boron electroless plating solution according to an embodiment of the present invention.

6 and 7, the nickel-boron electroless plating solution had a nickel ion composition of 0.1 M, a temperature of 60° C., and a composition of TBAB of 0.03 M.

Referring to FIG. 6 , local polarization curves for anode oxidation and cathode reduction of nickel ions in a plating solution when 0.03 M TBAB is used as a reducing agent under various pH conditions are shown. As the pH was changed to increase to 6, 7, and 8, the hybrid potential and current were -0.370 V / 6.03x10 ^-5 A, -0.405 V / 6.61x10 ^-5 A, and -0.502 V / 8.91x10, respectively. ^-5 A was shown. Therefore, as the pH was increased, the hybrid potential decreased and the current density increased. This trend is analyzed because the local cathode curve and the local anode curve shift toward a more reversible reaction by increased alkalinity in a uniform nickel composition. In addition, it is analyzed that the decrease in the hybrid potential as the pH is increased is because the local anode reaction is more affected by the pH than the local cathodic reaction.

Accordingly, TBAB may be reacted according to Schemes 1 and 2 below.

<Scheme 1>

<Scheme 2>

Here, “n” is a number ranging from 1 to 4.

The hydrogen atom (H) formed in Scheme 1 may be recombinated or oxidized to form water.

Referring to Schemes 1 and 2, it is analyzed that when the pH of the nickel-boron electroless plating solution is increased, the oxidation of the TBAB is accelerated.

Referring to FIG. 7 , the plating speed increased as the pH increased. This is consistent with the results of Schemes 1 and 2, and is consistent with the results of FIG. 6 .

From the electrochemical analysis results, it can be seen that the nickel-boron electroless plating solution using TBAB as a reducing agent in a 0.1 M nickel composition is optimized at a pH of 8 and a composition of 0.03 M TBAB.

Hereinafter, electroless plating is performed using a nickel-boron electroless plating solution optimized to a composition of 0.03 M TBAB and pH 8 to analyze the nickel-boron electroless plating layer.

As an example, in the nickel-boron electroless plating layer prepared using the nickel-boron electroless plating solution including TBAB, the nickel composition was 97 wt% and the boron composition was 3 wt%. However, this is exemplary, and the nickel-boron electroless plating layer may include nickel in a range of 95 wt% to 99 wt% and boron in a range of 1 wt% to 5 wt%.

On the other hand, as a comparative example, in the nickel-boron electroless plating layer prepared using dimethylamine borane, the composition of nickel was 98 wt% and the composition of boron was 2 wt%.

In order to analyze the etch resistance in the electrolyte of the nickel-boron electroless plating layer, 1 in a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of 1:1 An electrolyte was prepared including M LiPF ₆ , and the thickness of the specimen including the nickel-boron electroless plating layer of Examples and Comparative Examples in the electrolyte was maintained at 80° C. for 24 hours, and then the thickness was measured. Examples are cases in which TBAB is used as a reducing agent, and Comparative Examples are cases in which dimethylamine borane (DMAB) is used as a reducing agent.

8 is a graph showing the change in thickness before and after the nickel-boron electroless plating layer formed using the nickel-boron electroless plating method according to an embodiment of the present invention is immersed in the electrolyte.

Referring to FIG. 8 , in the case of the example, the thickness of the nickel-boron electroless plating layer was decreased from 23 μm to 21 μm, indicating a reduction rate of 8.7%. On the other hand, in the case of the comparative example, the thickness of the nickel-boron electroless plating layer was decreased from 25 μm to 21 μm, indicating a reduction rate of 16%.

In other words, the nickel-boron electroless plating layer is an electrolyte containing ethylene carbonate (EC), diethyl carbonate (DCE) and LiPF ₆ which are typically used as electrolytes of lithium ion batteries, more preferably ethylene carbonate (EC) In a mixture in which diethyl carbonate and diethyl carbonate are mixed in a volume ratio of 1:1, the thickness change is reduced to 10% or less, more preferably 8.7% or less after maintaining at 80° C. for 24 hours in an electrolyte containing 1 M LiPF ₆ in the mixture. decrease can be seen. It can be seen that compared to the comparative example using dimethylamine borane (DMAB), the reduction rate is reduced by 5% or more, more preferably by 7% or more.

That is, the nickel-boron electroless plating layer according to the embodiment of the present invention contains an electrolyte composed of ethylene carbonate (EC), diethyl carbonate (DCE) and LiPF ₆ , more preferably ethylene carbonate (EC) and diethyl carbonate by volume. It can be numerically confirmed that the etch resistance is excellent in the electrolyte including 1 M LiPF ₆ in the mixture mixed in a ratio of 1:1. For this reason, it can be seen that the amount of nickel reacting with the electrolyte is small in the Example, compared to the Comparative Example, and thus, the Example is analyzed to have better etching resistance.

9 is an optical micrograph showing the surface state of a nickel-boron electroless plating layer formed using a nickel-boron electroless plating method according to an embodiment of the present invention before and after immersion in an electrolyte.

Referring to FIG. 9 , after the nickel-boron electroless plating is performed, it can be seen that a nickel-boron electroless plating layer is formed on the copper surface. In general, when the etching resistance to the electrolyte is small, the plating layer may be peeled off or a local color change may be observed. However, after being immersed in the electrolyte at 80° C. for 24 hours, in both Examples and Comparative Examples, the nickel-boron electroless plating layer exhibited a smooth surface, and peeling or color change of the nickel-boron electroless plating layer was hardly observed. It didn't happen. That is, the nickel-boron electroless plating layer is an electrolyte containing ethylene carbonate (EC), diethyl carbonate (DCE) and LiPF ₆ used as electrolytes of lithium ion batteries, more preferably ethylene carbonate (EC) and It can be seen that the etch resistance in the electrolyte including 1 M LiPF ₆ in the mixture in which diethyl carbonate is mixed in a 1:1 volume ratio is improved.

10 is a scanning electron microscope photograph showing the surface state of a nickel-boron electroless plating layer formed by using a nickel-boron electroless plating method according to an embodiment of the present invention before and after immersion in an electrolyte.

Referring to FIG. 10 , in the case of the example, uniform semicircles were observed on the surface of the nickel-boron electroless plating layer. In the case of the comparative example, non-uniform pores were observed on the surface of the nickel-boron electroless plating layer, which is analyzed to be due to surface peeling by the electrolyte. Therefore, it is analyzed that the Example has better etching resistance than the Comparative Example, which is consistent with the result of FIG. 8 .

As a result, TBAB has unique advantages over dimethylamine borane, such as superior etch resistance, and can be used as a reducing agent to form stable nickel-boron electroless plating layers.

conclusion

Nickel-boron electroless plating layers were successfully formed using an electroless plating method using TBAB as a reducing agent. From the electrostatic polarization analysis, a nickel-boron electroless plating solution using TBAB as a reducing agent at a nickel composition of 0.1 M was optimized at a composition of the TBAB of 0.03 M, a temperature of 60° C., and a pH of 8. The nickel-boron electroless plating layer formed by exposure to the optimized nickel-boron electroless plating solution for 90 seconds exhibited excellent etch resistance and high temperature stability in the electrolyte.

In particular, the nickel-boron electroless plating layer using TBAB as a reducing agent is a mixture of ethylene carbonate (EC) and diethyl carbonate in a 1:1 volume ratio, which are commonly used as electrolytes for lithium ion batteries, and 1 M LiPF in the mixture. It can be seen that the weight reduction rate after maintaining at 80° C. for 24 hours in an electrolyte containing ₆ is 5% or more, more preferably 7% or more, compared to the comparative example using dimethylamine borane (DMAB).

That is, in particular, the nickel-boron electroless plating layer using TBAB as a reducing agent is an electrolyte containing ethylene carbonate (EC), diethyl carbonate (DCE) and LiPF6, which are typically used as electrolytes for lithium ion batteries, more preferably carbonate It can be seen that the etch resistance in the electrolyte including 1 M LiPF ₆ in the mixture in which ethylene (EC) and diethyl carbonate are mixed in a volume ratio of 1:1 is improved.

Therefore, the outstanding properties of the Ni-B electroless plating layer can be realized using TBAB as a reducing agent, and this technique can be extended to the manufacture of other nickel-boron electroless plating layers.

The technical spirit of the present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is the technical spirit of the present invention that various substitutions, modifications and changes are possible without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in the art to which this belongs.

10: plating apparatus, 20: plating bath.
30: nickel-boron electroless plating solution,
40: metal plating object, 50: plating layer,

Claims (15)

a nickel metal salt providing nickel ions for plating;
a reducing agent that reduces the nickel ions for plating and includes tert-butyl amine borane (TBAB) in the range of 0.01 M to 0.05 M;
a complexing agent for forming a complex with the nickel ion for plating; and
A stabilizer that suppresses the reduction reaction of nickel ions for plating;
Nickel-boron electroless plating solution for electrode terminal plating of lithium ion batteries. The method of claim 1,
Nickel-boron electroless plating solution for electrode terminal plating of the lithium ion battery,
Nickel sulfate hexahydrate in the range of 0.05 M to 0.2 M as the nickel metal salt;
Citric acid in the range of 0.05 M to 0.2 M as the complexing agent;
lead nitrate in the range of 1 ppm to 3 ppm as the stabilizer; and
Containing; TBAB in the range of 0.01 M to 0.05 M as the reducing agent;
Nickel-boron electroless plating solution for electrode terminal plating of lithium ion batteries. The method of claim 1,
The nickel metal salt includes at least one of nickel sulfate, nickel chloride, nickel sulfamic acid, nickel nitrate, nickel oxide, and nickel carbonate,
Nickel-boron electroless plating solution for electrode terminal plating of lithium ion batteries. The method of claim 1,
The complexing agent, acetic acid, adipic acid, formic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecylic acid acid), myristic acid, pentadecanoic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, oxalic acid (oxalic acid), malonic acid, tartaric acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid (azelaic acid), sebacic acid, ortho-phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, Among glutaconic acid, traumatic acid, and muconic acid, glycolic acid, lactic acid, citric acid, and mandelic acid A nickel-boron electroless plating solution for plating an electrode terminal of a lithium ion battery comprising at least one. The method of claim 1,
The stabilizer includes at least one of lead (Pb), telenium (Te), selenium (Se), bismuth (Bi), tin (Sn), thallium (Tl), and molybdenum (Mo),
Nickel-boron electroless plating solution for electrode terminal plating of lithium ion batteries. The method of claim 1,
The nickel-boron electroless plating solution for plating the electrode terminal of the lithium ion battery further comprises at least one of a pH adjuster, an auxiliary additive, and a surfactant,
Nickel-boron electroless plating solution for electrode terminal plating of lithium ion batteries. The method of claim 1,
The nickel-boron electroless plating solution for electrode terminal plating of the lithium ion battery has a pH in the range of 6 to pH 8,
Nickel-boron electroless plating solution for electrode terminal plating of lithium ion batteries. immersing the metal plating object in an etching solution;
nickel strike electrolytic plating of the metal plating object; and
A method of electroless plating the metal plating object using the nickel-boron electroless plating solution containing TBAB according to any one of claims 1 to 7 to form a nickel-boron electroless plating layer;
Nickel-boron electroless plating method of electrode terminals of lithium ion batteries. 9. The method of claim 8,
Forming the nickel-boron electroless plating layer,
containing nickel sulfate hexahydrate in the range of 0.05 M to 0.2 M as the nickel metal salt, citric acid in the range of 0.05 M to 0.2 M as the complexing agent, and lead nitrate in the range of 1 ppm to 3 ppm as the stabilizer, Performed using the nickel-boron electroless plating solution comprising the TBAB in the range of 0.01 M to 0.05 M as the reducing agent,
Nickel-boron electroless plating method of electrode terminals of lithium ion batteries. 9. The method of claim 8,
After performing the step of immersing in the etching solution, after performing the nickel strike electrolytic plating step, and after performing the step of forming the nickel-boron electroless plating layer, the metal plating object using deionized water Each further comprising the step of washing by
Nickel-boron electroless plating method of electrode terminals of lithium ion batteries. 9. The method of claim 8,
The step of immersing in the etching solution is carried out for a time in the range of 10 seconds to 20 seconds at a temperature in the range of 20 ° C to 30 ° C using a sulfuric acid solution in the range of 5% to 10%,
Nickel-boron electroless plating method of electrode terminals of lithium ion batteries. 9. The method of claim 8,
The nickel strike electrolytic plating step includes:
NiCl ₂ in the range of 40 g/L to 50 g/L, NiSO ₄ 6 (H ₂ O) in the range of 200 g/L to 300 g/L, and H ₃ BO ₃ in the range of 25 g/L to 30 g/L Using a nickel strike electrolytic plating solution containing,
carried out under process conditions wherein a pH in the range of pH 4 to pH 5, a temperature in the range of 40° C. to 60° C., and a voltage in the range of 5 V to 7 V are applied for an application time in the range of 10 seconds to 15 seconds,
Nickel-boron electroless plating method of electrode terminals of lithium ion batteries. 9. The method of claim 8,
Forming the nickel-boron electroless plating layer,
carried out at process conditions of a pH in the range of pH 6 to pH 8 and a temperature in the range of 50° C. to 70° C.
Nickel-boron electroless plating method of electrode terminals of lithium ion batteries. metal plating object; and
A nickel-boron electroless plating layer formed by electroless plating by a nickel-boron electroless plating solution containing TBAB in the range of 0.01 M to 0.05 M according to any one of claims 1 to 7 on the surface of the metal plating object including;
Electrode terminals of lithium ion batteries. 15. The method of claim 14,
The nickel-boron electroless plating layer comprises 95 wt% to 99 wt% nickel and 1 wt% to 5 wt% boron,
Electrode terminals of lithium ion batteries.

Images