TWI435352B - Aluminum foil having high specific surface area and manufacturing method thereof - Google Patents

Description

High specific surface area aluminum material and preparation method thereof

The invention relates to an aluminum material and a preparation method thereof, in particular to a high specific surface area aluminum material and a preparation method thereof.

Electrochemical related electronic components are widely used in various fields, for example, battery systems utilize electrochemical reactions to achieve charge discharge or repeated charge charging/discharging operations, and thus are used as power supplies for various electronic machines.

In addition, an electrolytic capacitor is a component capable of storing electric charge, and the capacitor can instantaneously store and discharge electricity. In application, the capacitor is mainly used as a blocking DC, coupled alternating current, filtering, tuning, phase shifting, storing energy, and being used as a side. Circuits, coupling circuits, networks of speaker systems, etc., are even used for power storage/discharge applications such as flashlights in cameras.

In the above elements, it is necessary to increase the overall characteristics of the element with a large-area electrode structure. Taking an electrolytic capacitor as an example, the anode electrode and the cathode electrode are both made of aluminum foil, and in the electrode manufacturing process, the high-purity aluminum foil needs to be electrically or chemically etched to form an uneven surface on the aluminum foil, thereby improving the aluminum foil. The surface area increases the relative capacitance of the capacitor; in other words, the electrolytic capacitor can enlarge the surface area of the electrode by an etching method, and in recent years, the industry has developed a technique of attaching carbon powder to the surface of the aluminum foil to enlarge the surface area of the electrode.

However, the aluminum powder obtained by the above method is coated with carbon powder. Material, because the adhesion between carbon powder and aluminum surface is not good. Therefore, when such a poorly bonded electrode is applied to a secondary battery or a capacitor, a phenomenon in which the carbon powder is peeled off from the surface of the aluminum material may occur during charging and discharging of the secondary battery or the capacitor.

One of the objects of the present invention is to provide an aluminum material which can improve the adhesion between an aluminum substrate and an active layer, and a method for producing the same. The aluminum material produced by the invention can have a high specific surface area by the particles of the activation layer, so when the aluminum material of the invention is fabricated into an electrode structure, it can provide more reaction area and the bonding area with other materials, so A high-performance electrode structure is formed.

An embodiment of the present invention provides a high specific surface area aluminum material comprising: an aluminum substrate and a plurality of particles formed on a surface of the aluminum substrate; wherein the particles are made of at least aluminum and aluminum compounds. One of the particles has a connection structure between the particles and the surface of the aluminum substrate.

An embodiment of the present invention provides a method for fabricating a high specific surface area aluminum material, comprising the steps of: providing an aluminum substrate; and attaching particles of at least one of the materials of aluminum and aluminum to the surface of the aluminum substrate; The shaped joint structure is between the particles or between the particles and the surface of the aluminum substrate.

The present invention has the following beneficial effects: the present invention can utilize the particles in the active layer to produce a relatively high surface area to help improve the electrical conductivity of the aluminum material, so the high specific surface area aluminum material of the present invention can be used to produce high Electrode structure with electrical characteristics; on the other hand, using the electrode structure described above The element may have better electrical characteristics due to the characteristics of the electrode structure, such as having a high charge and discharge efficiency.

For a better understanding of the features and technical aspects of the present invention, reference should be made to the accompanying drawings.

The invention provides a high specific surface area aluminum material and a preparation method thereof, and the high specific surface area aluminum material proposed by the invention mainly comprises one or more structures composed of aluminum particles or/and aluminum compound particles on an aluminum substrate, The structure may have a high specific surface area, which can be applied to a conductive electrode to increase the reaction area of the electrode, thereby improving the characteristics of the element having the above electrode.

As shown in FIG. 1, it is an embodiment of the high specific surface area aluminum material of the present invention, wherein a plurality of particles 21 are formed on one surface of the aluminum substrate 1, and the particles 21 can be laminated to form an active layer. 2. The active layer 2 can be used to increase the overall surface area of the aluminum material to improve the characteristics of the electrical components to which it is applied. In addition, a connection structure 22 may be formed between the particles 21 and the particles 21 or/and between the particles 21 and the aluminum substrate 1. The connection structure 22 may be formed by extending the surface of the particles 21 to be connected to other particles 21 or an aluminum substrate. The structure of 1 and the connecting structure 22 can further enhance the surface area of the aluminum material, and further enhance the adhesion of the active layer 2 itself and the bonding strength between the aluminum substrate 1 and the active layer 2.

Referring to FIG. 3, the steps of the method for fabricating the high specific surface area aluminum material of the present invention will be described below:

Step (1): An aluminum substrate 1 is provided. The aluminum substrate 1 of the present invention does not have In particular, it is preferable to use pure aluminum or an aluminum alloy, and the aluminum content of the aluminum substrate 1 is preferably 99% or more in accordance with the method described in the European Union Standard "EN 576-1995". The composition of the aluminum substrate 1 used in the present invention is lead (Pb), bismuth (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), chromium (Cr), zinc (Zn). An aluminum alloy in which at least one element of titanium (Ti), vanadium (V), gallium (Ga), nickel (Ni), and boron (B) is added within a necessary range; The thickness is not particularly limited, and is preferably 5 μm or more and 200 μm or less in the case of aluminum foil, and preferably 200 μm or more and 3 mm or less in the case of an aluminum plate.

The aluminum substrate 1 described above can be produced by any known method. For example, aluminum or an aluminum alloy having a molten state of a predetermined composition is adjusted, and the ingot obtained by casting is appropriately homogenized, and then the ingot is subjected to hot rolling and cold rolling to obtain a desired Aluminum. Further, in the cold rolling step, an annealing treatment in a range of 150 ° C or more and 400 ° C or less may be applied.

Step (2): The particles 21 are attached to the surface of the aluminum substrate 1. In this step, the particles 21 of at least one of the aluminum and aluminum compounds are mainly formed on the surface of the aluminum substrate 1 to form the active layer 2, and the method used in the step may include at least a physical method and a chemical method, in which the physical method is also called an evaporation-condensation method, the principle is that in a high vacuum environment and a low-pressure inert gas (such as argon gas, helium gas), the aluminum block is vaporized by the heating of the evaporation source, and then The surface of the aluminum substrate 1 is condensed to deposit the particles 21. In addition, the evaporation-condensation method can be further divided into a laser-induction heating method, a plasma heating method, an electron beam irradiation method, and the like according to the design of the machine.

In the laser-induction heating method, a method of depositing particles 21 of aluminum on the surface of the aluminum substrate 1 is firstly carried out by inductively heating the aluminum material to raise the temperature to a temperature of melting or higher, and then introducing a laser to utilize a thunder. The input of the generated energy causes the molten aluminum raw material to evaporate under a vacuum or a low-pressure protective atmosphere, and deposits it on the surface of the aluminum substrate 1 in the form of particles, and the aluminum of 2 to 50 nm can be produced by the above method. The particles 21 are on the surface of the aluminum substrate 1.

On the other hand, chemical methods may include a gas phase chemical reaction method, a solid phase chemical reaction method, a thermal decomposition method, a liquid phase chemical reaction method, a combustion synthesis method, and the like. For example, by preparing a particle 21 of aluminum nitride (AlN) on the surface of the aluminum substrate 1 by a gas phase chemical reaction method, the following reaction formula can be used: AlCl _{3 (g)} +4 NH _{3 (g)} → AlN _{(s )} +3 NH ₄ Cl _(g)

The reaction is carried out at a temperature of 900 to 1500 K to prepare aluminum nitride (AlN) particles 21 on the surface of the aluminum substrate 1; or the following reaction formula is used:

The reaction is carried out at a temperature of 1300 to 2000 K (preferably 1500 to 2000 K) to prepare particles of aluminum nitride 21 on the surface of the aluminum substrate 1.

In another aspect, in this step, the active layer 2 formed by the particles 23 of titanium aluminum nitride (TiAlN) can also be formed by a physical vapor deposition system in a physical method. In a specific embodiment, the present invention employs a cathodic arc. Deposition The method comprises the steps of depositing particles 23 of aluminum nitride titanium, the principle of which is to induce a cathodic arc near the target source by using an arc trigger, to generate a glow discharge with a high current and a low voltage in a high vacuum environment, and to form a cathode arc point on the surface of the target. Potholes. Due to the local high temperature, high pressure and explosion phenomenon formed after the cathode arc point is generated, the molten pool of the micro-pits is formed on the surface of the target, thereby releasing the target particles, and the size of the particles is composed of arc current, gas composition and pressure. It is decided that in the embodiment, the target is 50% Ti-50% Al, the target current is 50 to 100 amps, the chamber pressure is 0.1 to 0.3 Pa, and the gas is argon and nitrogen, and the diameter is about The 25 um aluminum nitride titanium particles 21 can be ejected from the cathode source and deposited on the surface of the aluminum substrate 1.

In summary, this step mainly forms particles 21 of aluminum particles 21 and/or aluminum compounds (such as aluminum nitride, titanium aluminum nitride or other aluminum metal compounds, etc.) on the surface of the aluminum substrate 1, and the above The methods are all illustrative and are not intended to limit the invention, and the particles 21 of aluminum and/or aluminum compound may be formed on the aluminum substrate 1 by any feasible technique without being limited by the above embodiments.

Step (3): The molded joint structure 22 is between the particles 21 and the particles 21 or between the particles 21 and the surface of the aluminum substrate 1. In this step, the connection structure 22 is mainly grown. It should be noted that the connection structure 22 can be performed together in the step (2), but is specifically explained in step (3) for convenience of explanation. The connecting structure 22 is a mixture of whiskers (or whiskers) or whiskers and micro-particles, and the whiskers are short-sized short fibers which are formed in a single crystal structure under certain conditions, because The diameter is extremely small, so the defects in the whiskers are small, and the strength is close to the theoretical value of the bonding force between the atoms of the material, generally up to 10 ⁴ MPa or more, and the present invention is mainly between the particles 21 and 21 or the particles 21 and the aluminum substrate. A mixture of aluminum whiskers and whiskers of an aluminum-nitrogen mixture is formed between the surfaces of 1 to form the joint structure 22. In this step, the surface of the particles 21 may be elongated by the high temperature, and the position of the aluminum whisker may be formed between the particles 21 and the particles 21 or between the particles 21 and the surface of the aluminum substrate 1. Therefore, the overall bonding strength can be improved. The whisker of the aluminum nitride compound refers to a mixture of aluminum nitride or other mixed ratio of nitrogen/aluminum.

Specifically, the aluminum whisker of the present invention may be different depending on the material of the particles 21 of the active layer 2. In a specific embodiment, the particles 21 of the active layer 2 are made of aluminum nitride, so the connection structure 22 is nitrided. Aluminum whiskers, and in a specific step, aluminum nitride whiskers may be produced by a carbothermal reduction method, or aluminum nitride whiskers may be produced by a recrystallization method under a normal nitrogen atmosphere.

As described above, the present invention can also integrate steps (2) and (3), for example, directly on the surface of the aluminum substrate 1 by self-propagating high temperature synthesis (SHS). The active layer 2 has particles of aluminum nitride whiskers and aluminum nitride 21 at the same time.

Therefore, by the above steps, the present invention can produce a high specific surface area aluminum material composed of the aluminum substrate 1 and the active layer 2, and the thickness of the active layer 2 can vary depending on the field of application, such as an active layer. The thickness of 2 may range from 2 nanometers (nm) to several centimeters (mm).

The high specific surface area aluminum material of the present invention is preferably applicable to an electrode structure, such as an electrode structure of a capacitor, and the capacitor can be double-layered. The container, the aluminum electrolytic capacitor, the solid electrolytic capacitor, and the like, and the high specific surface area aluminum material of the present invention can effectively improve the capacitance characteristics, internal resistance characteristics, charge and discharge characteristics, service life, and the like of the capacitor. In the electrode structure applied to the capacitor, the thickness of the active layer 2 of the high specific surface area aluminum material of the present invention may be selected from 2 nanometers (nm) to several micrometers (um) to conform to the use of the solid electrolytic capacitor; or the active layer The thickness of 2 can be selected from several micrometers to several centimeters to meet the use of supercapacitors.

Moreover, the high specific surface area aluminum material of the present invention is preferably applicable to an electrode structure, such as an electrode structure of an electrochemical cell, and the electrochemical cell can be an electrolytic cell of a lithium ion battery or the like, and the high specific surface area of the present invention. Aluminum can effectively improve battery capacity characteristics, internal resistance characteristics, charge and discharge characteristics, and service life.

On the other hand, as shown in FIG. 2, the high specific surface area aluminum material of the second embodiment of the present invention, wherein the upper and lower surfaces (ie, both sides) of the aluminum substrate 1 are formed with the active layer 2, and related The manufacturing method can refer to the foregoing content, and will not be described here.

In summary, the present invention has at least the following advantages:

1. The high specific surface area aluminum material produced by the invention can produce a relatively high surface area by using particles in the active layer, and helps to improve the conductivity of the aluminum material, so that the high specific surface area aluminum material of the invention can be used. An electrode structure with high electrical properties.

2. According to the invention, the high specific surface area aluminum material produced by the invention has a high surface area, so when applied to a capacitor, a high strength adhesion can be formed between the electrode made of the high specific surface area aluminum material and the polymer material. Therefore, the characteristics and reliability of the components can be improved.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and the equivalents of the present invention are intended to be included within the scope of the present invention.

1‧‧‧Aluminum substrate

2‧‧‧Active layer

21‧‧‧ particles

22‧‧‧ Connection structure

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a high specific surface area aluminum material according to a first embodiment of the present invention.

Fig. 2 is a schematic view showing a high specific surface area aluminum material according to a second embodiment of the present invention.

Fig. 3 is a flow chart showing a method of producing a high specific surface area aluminum material of the present invention.

1‧‧‧Aluminum substrate

2‧‧‧Active layer

21‧‧‧ particles

22‧‧‧ Connection structure

Claims (13)

A high specific surface area aluminum material comprising: an aluminum substrate and a plurality of particles formed on a surface of the aluminum substrate; wherein the particles are made of at least one of aluminum and an aluminum compound, and the particles are There is a connection structure between the particles and the surface of the aluminum substrate, and the connection structure is at least one of whiskers and a mixture of microparticles and whiskers. The high specific surface area aluminum material according to claim 1, wherein the aluminum compound is aluminum nitride or aluminum titanium nitride. The high specific surface area aluminum material according to claim 1, wherein the aluminum compound is a metal compound of aluminum. The high specific surface area aluminum material according to claim 1, wherein the joint structure is a mixture of aluminum whisker and aluminum nitrogen mixture whiskers. The high specific surface area aluminum material according to claim 4, wherein the connecting structure is selectively grown between the particles or between the particles and the surface of the aluminum substrate. The high specific surface area aluminum material according to claim 1, wherein the particles are deposited on one or both sides of the aluminum substrate. A method for fabricating a high specific surface area aluminum material, comprising the steps of: providing an aluminum substrate; attaching particles of at least one of aluminum and aluminum compounds to a surface of the aluminum substrate; and forming a connection structure Between the particles or between the particles and the surface of the aluminum substrate, wherein the connecting structure is whiskers and micro-particles At least one of a mixture of granules and whiskers. The method for producing a high specific surface area aluminum material according to claim 7, wherein the step of attaching particles of at least one of the materials of aluminum and aluminum to the surface of the aluminum substrate utilizes physics The particles are formed by methods or chemical methods. The method for manufacturing a high specific surface area aluminum material according to claim 8, wherein the physical method is laser-induction heating, plasma heating or electron beam irradiation, and the chemical method is gas. Phase chemical reaction method, solid phase chemical reaction method, thermal decomposition method, liquid phase chemical reaction method or combustion synthesis method. The method for producing a high specific surface area aluminum material according to claim 8, wherein the aluminum compound is aluminum nitride or aluminum nitride titanium, or the aluminum compound is a metal compound of aluminum. The method for producing a high specific surface area aluminum material according to claim 8, wherein the particles are deposited on one side or both sides of the aluminum substrate. The method for producing a high specific surface area aluminum material according to claim 7, wherein in the step of forming the joint structure, the joint structure is a mixture of aluminum whisker and aluminum nitrogen mixture whiskers. The method for producing a high specific surface area aluminum material according to claim 11 or claim 12, wherein the connecting structure is selectively grown between the particles or the surface of the particles and the aluminum substrate. between.