鋁電解電容器用陽極箔增容技術(shù)基礎(chǔ)研究
發(fā)布時間：2019-01-11 14:23
【摘要】：鋁電解電容器因其優(yōu)良的性能、低廉的價格及可靠的質(zhì)量在通訊市場、生活電器領(lǐng)域、工業(yè)領(lǐng)域等得到了廣泛的應(yīng)用。同時,電子產(chǎn)品的快速發(fā)展也對鋁電解電容器的小型化、高比容等性能提出了更高的要求。而實現(xiàn)電解電容器小型化、高比容的關(guān)鍵技術(shù)在于有效提高陽極箔的電容。陽極箔的電容計算公式為C=(εε0S)/d,其中ε0為真空介電常數(shù)(8.85×10-12(F·m-1)),S表示電極板的有效面積,d表示的氧化膜的厚度。無論A1203是無定形結(jié)構(gòu)還是晶形結(jié)構(gòu),其相對介電常數(shù)ε是確定的,在8～10之間。氧化膜的厚度d可以用公式d=Ea.K表示,其中Ea表示化成電壓,K表示氧化膜的形成常數(shù)。為此,當(dāng)化成電壓Ea一定時,d是一定的,很難通過減小d的數(shù)值來提高比電容�；谏鲜龇治�,本文通過在腐蝕工藝中引入超聲強(qiáng)化傳質(zhì)來改善鋁箔的發(fā)孔狀態(tài),即通過優(yōu)化蝕孔形貌,增大S繼而提高C;其次,在化成工藝中引入Ti02-Al203復(fù)合介電膜層來增大ε,繼而提高C。主要的研究內(nèi)容及結(jié)論如下:(1)在輔助超聲條件下,通過直流電解腐蝕制備高壓電極鋁箔。具體通過計時電位、動電位極化、循環(huán)伏安、交流阻抗等測試手段,詳細(xì)研究了超聲強(qiáng)化傳質(zhì)對腐蝕箔的電化學(xué)行為及界面行為的作用規(guī)律。采用XRD能譜、掃描電鏡及低溫N2吸附等手段對腐蝕箔進(jìn)行表征。結(jié)果表明超聲攪拌作用有效抑制了氧化鋁膜的生長,通過增加氧化鋁/電解液界面處C1-的吸附量促進(jìn)了點蝕的萌生,通過減小氧化鋁/電解液界面處擴(kuò)散層的厚度,即減小電解液的傳質(zhì)阻力,強(qiáng)化了 Cl-向孔內(nèi)以及生成產(chǎn)物A13+、A1C13向孔外的擴(kuò)散。最終,超聲輔助制備的腐蝕箔的雙電層電容Cdl、蝕孔密度、平均蝕孔孔徑/平均蝕孔深度及孔徑/孔深的均一性都得到了提高。(2)運(yùn)用溶膠—凝膠法在腐蝕箔表面引入了 TiO2閥金屬氧化物,化成處理后獲得了高介電常數(shù)的Al2O3-TiO2復(fù)合介電膜層。用掃描電鏡、EDS能譜以及XRD能譜分析了氧化膜的表面形貌、成分及腐蝕箔截面處Ti元素的分布特點。研究結(jié)果表明,經(jīng)過550 ℃C熱處理后,銳鈦礦型Ti02已成功獲得,但隨著涂覆量的增加,蝕孔孔徑減小且被堵塞的幾率變大,涂層缺陷更易形成。此外,氧化膜的升壓曲線、動電位極化曲線以及交流阻抗曲線的分析結(jié)果表明,當(dāng)單位腐蝕箔表面Ti的涂覆量為4.4 mg·cm-2時,化成階段消耗的形成電量最小,相對無涂層腐蝕箔減少了 85%,與之對應(yīng)的化成箔的比容達(dá)到最大值(54.16μF·cm-2),相對無涂層化成箔比容增加了 25.84%。
[Abstract]:Aluminum electrolytic capacitors have been widely used in communication market, household appliances and industrial fields because of their excellent performance, low price and reliable quality. At the same time, the rapid development of electronic products also put forward higher requirements for the miniaturization and high specific capacity of aluminum electrolytic capacitors. The key technology to realize the miniaturization and high specific capacity of electrolytic capacitor is to increase the capacitance of anode foil effectively. The capacitance formula of anodic foil is C = (蔚 -0S) / d, where 蔚 _ 0 is the vacuum dielectric constant (8.85 脳 10 ~ (-12) (F _ m ~ (-1), S) is the effective area of the electrode plate and d is the thickness of the oxide film. Regardless of whether A1203 is amorphous or crystalline, the relative dielectric constant 蔚 is determined between 810 and 10. The thickness d of the oxide film can be expressed by the formula d=Ea.K, where Ea denotes the formation voltage and K represents the formation constant of the oxide film. For this reason, when the formation voltage Ea is constant, d is certain, so it is difficult to increase the specific capacitance by reducing the value of d. Based on the above analysis, ultrasonic enhanced mass transfer is introduced into the corrosion process to improve the formation of aluminum foil, that is to say, by optimizing the morphology of the etching hole, increasing S and then increasing the C; Secondly, the Ti02-Al203 composite dielectric layer was introduced to increase 蔚 and then to increase C. The main research contents and conclusions are as follows: (1) High voltage electrode aluminum foil was prepared by direct current electrolysis under the condition of assisted ultrasound. By means of chronopotentiometry, potentiodynamic polarization, cyclic voltammetry and AC impedance, the effect of ultrasonic enhanced mass transfer on the electrochemical behavior and interface behavior of corrosion foil was studied in detail. Corrosion foil was characterized by XRD, SEM and N2 adsorption at low temperature. The results show that ultrasonic stirring can effectively inhibit the growth of alumina membrane, promote the initiation of pitting corrosion by increasing the adsorption of C1- at the interface of alumina / electrolyte, and decrease the thickness of diffusion layer at the interface of alumina / electrolyte. By reducing the mass transfer resistance of the electrolyte, the diffusion of Cl- into the pore and the formation products A13 and A1C13 out of the pore was strengthened. Finally, ultrasonic assisted preparation of the double-layer capacitance Cdl, etching hole density of the etched foil, The uniformity of average pore diameter / average hole depth and pore diameter / hole depth were improved. (2) TiO2 valve metal oxide was introduced on the surface of corroded foil by sol-gel method. The Al2O3-TiO2 composite dielectric film with high dielectric constant was obtained. The surface morphology, composition and distribution of Ti elements in the section of the corrosion foil were analyzed by SEM, EDS and XRD spectra. The results show that anatase Ti02 has been successfully obtained after heat treatment at 550 鈩，
本文編號：2407233
[Abstract]:Aluminum electrolytic capacitors have been widely used in communication market, household appliances and industrial fields because of their excellent performance, low price and reliable quality. At the same time, the rapid development of electronic products also put forward higher requirements for the miniaturization and high specific capacity of aluminum electrolytic capacitors. The key technology to realize the miniaturization and high specific capacity of electrolytic capacitor is to increase the capacitance of anode foil effectively. The capacitance formula of anodic foil is C = (蔚 -0S) / d, where 蔚 _ 0 is the vacuum dielectric constant (8.85 脳 10 ~ (-12) (F _ m ~ (-1), S) is the effective area of the electrode plate and d is the thickness of the oxide film. Regardless of whether A1203 is amorphous or crystalline, the relative dielectric constant 蔚 is determined between 810 and 10. The thickness d of the oxide film can be expressed by the formula d=Ea.K, where Ea denotes the formation voltage and K represents the formation constant of the oxide film. For this reason, when the formation voltage Ea is constant, d is certain, so it is difficult to increase the specific capacitance by reducing the value of d. Based on the above analysis, ultrasonic enhanced mass transfer is introduced into the corrosion process to improve the formation of aluminum foil, that is to say, by optimizing the morphology of the etching hole, increasing S and then increasing the C; Secondly, the Ti02-Al203 composite dielectric layer was introduced to increase 蔚 and then to increase C. The main research contents and conclusions are as follows: (1) High voltage electrode aluminum foil was prepared by direct current electrolysis under the condition of assisted ultrasound. By means of chronopotentiometry, potentiodynamic polarization, cyclic voltammetry and AC impedance, the effect of ultrasonic enhanced mass transfer on the electrochemical behavior and interface behavior of corrosion foil was studied in detail. Corrosion foil was characterized by XRD, SEM and N2 adsorption at low temperature. The results show that ultrasonic stirring can effectively inhibit the growth of alumina membrane, promote the initiation of pitting corrosion by increasing the adsorption of C1- at the interface of alumina / electrolyte, and decrease the thickness of diffusion layer at the interface of alumina / electrolyte. By reducing the mass transfer resistance of the electrolyte, the diffusion of Cl- into the pore and the formation products A13 and A1C13 out of the pore was strengthened. Finally, ultrasonic assisted preparation of the double-layer capacitance Cdl, etching hole density of the etched foil, The uniformity of average pore diameter / average hole depth and pore diameter / hole depth were improved. (2) TiO2 valve metal oxide was introduced on the surface of corroded foil by sol-gel method. The Al2O3-TiO2 composite dielectric film with high dielectric constant was obtained. The surface morphology, composition and distribution of Ti elements in the section of the corrosion foil were analyzed by SEM, EDS and XRD spectra. The results show that anatase Ti02 has been successfully obtained after heat treatment at 550 鈩，
本文編號：2407233
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