Method for improving specific volume of an aluminum electrode foil by electrochemical deposition method

Abstract

The invention relates to an aluminum electrolytic capacitor, in particular to a method for improving specific volume of an aluminum electrode foil by an electrochemical deposition method. In the invention, an Al2O3/TiO2 composite dielectric film is prepared on the surface of the electrode foil by adopting a cathodic electrochemical deposition technology. The preparation process of the composite dielectric film comprises the following steps: taking metallic titanium as an anode, taking an aluminum etched foil as a cathode, and carrying out electro-deposition in an organic solvent-acetone containing halogen-iodine; depositing a titanium-containing compound layer on the surface of the etched foil, and then carrying out heat treatment; and finally carrying out anodic oxidation treatment so asto obtain the aluminum-titanium composite dielectric film with high dielectric constant on the surface of the etched foil. Compared with the traditional dielectric film, the composite dielectric filmon the surface of the aluminum electrode foil obtained by the technological process has higher dielectric constant under the condition of equal thickness so as to more effectively improve the specific capacity of the aluminum electrode foil. The method has the advantages of simple process and lower cost, and is convenient for operation and easy to control.

Description

technical field [0001] The invention relates to an aluminum electrolytic capacitor, in particular to a method for increasing the specific volume of an aluminum electrode foil by using an electrochemical deposition method. The aluminum electrode foil prepared by the invention is mainly used in an aluminum electrolytic capacitor. Background technique [0002] With the rapid development of the electronics industry and the rapid expansion of the market for products such as computers, communication products and home appliances, the demand for aluminum electrolytic capacitors has also risen sharply. At present, the development trend of aluminum electrolytic capacitors is miniaturization, chip type, high temperature resistance and long life. Therefore, high specific capacitance electrode foil manufacturing technology has become the key to manufacturing high-quality aluminum electrolytic capacitors; The surface area is directly proportional to the dielectric constant. The improvemen...

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Problems solved by technology

At present, the development trend of aluminum electrolytic capacitors is miniaturization, chip type, high temperature resistance and long life. Therefore, high specific capacitance electrode foil manufacturing technology has become the key to manufacturing high-quality aluminum electrolytic capacitors; The surface area is directly proportional to the dielectric constant. The improvement of the specific volume by electrochemical corrosion of aluminum foil in acid medium has reached a bottleneck. Therefore, the introduction of high dielectric constant metal (ceramic) matrix and aluminum matrix to form a composite oxide film, Improving the dielectric constant of the dielectric layer is an effective way to increase the specific capacity; although common methods for preparing composite films on the surface of electrode foils include sputtering, sol-gel, hydrolytic deposition, and alloying. These methods can increase the specific volume of aluminum foil in varying degrees, but these methods show many shortcomings, such as the general process cycle is long, the production cost is high, the environmental pollution is serious, and it is difficult to large-scale industrialization. There are few reports on the preparation of composite films by electrochemical deposition. Cathodic electrochemical deposition is used to deposit valve metal oxides on the surface of corroded foils, thereby increasing the specific capacity of electrode foils. Although some researchers have reported the use of electrochemical deposition in aqueous solution The inorganic salt of titanium is deposited on the surface of the cathode corrosion foil, but because many titanium salts are easily hydrolyzed in water to form titanium hydroxide precipitation, the selection and requirements of the solution are relatively strict, and it is difficult to prepare a titanium-aluminum composite with good performance on the surface film, so the present invention has tried a new electrochemical deposition method to successfully prepare a composite film on the surface of the electrode foil

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