Solid electrolytic capacitor is prepared the polymeric solution of solid electrolyte layer[technical field]
The present invention relates to a kind of solid electrolytic capacitor and prepare the polymeric solution of solid electrolyte layer.
[background technology]
The production technology of preparing at present solid electrolytic capacitor can adopt following steps to carry out: on capacitor anode surface, form oxide film dielectric; On oxide film dielectric outer surface, form solid electrolyte layer; At solid electrolyte layer outer surface, form carbon containing cathode layer; At carbon containing cathode layer outer surface, form silver-contained cathode layer; Make capacitor element, capacitor element is assembled and encapsulated, make solid electrolytic capacitor.Wherein, the solid electrolytic capacitor that the valve metal of take is aluminium is example, the operation that forms solid electrolyte layer on oxide film dielectric outer surface can be that the technique by chemical polymerization forms solid electrolyte layer on aluminium foil surface separately, or first the technique by chemical polymerization forms the first solid electrolyte layer on aluminium foil surface, and then the method by electrochemical polymerization forms the second solid electrolyte layer in the first solid electrolyte layer surface.
Along with the development of science and technology, market more and more needs that volume is little, capacity is large, loss is low, ESR is low, the capacitor that reliability is high.Conventionally adopt chemical polymerization or chemistry and electrochemical polymerization in conjunction with the conducting polymer of preparation pyrroles, aniline, thiophene or derivatives thereof, to form the solid electrolyte layer of solid electrolytic capacitor.Wherein, conducting polymer is in the coverage rate on valve metal oxide-film surface, and the conductivity of conductive polymer coating and the factors such as density of film forming directly have influence on the capacity of capacitor, ESR and reliability.
The shortcoming of prior art is: in the production process of capacitor, on valve metal surface, prepare the conductive polymer period of the day from 11 p.m. to 1 a.m, because the micropore of " cellular-shaped " on valve metal oxide-film surface lacks planarization, the solution of conducting polymer monomer is difficult to penetrate into completely in inner micropore, cause the conducting polymer of formation can not fully cover the whole of valve metal surface, thereby the capacity of electric solid electrolytic container can not be drawn well, so capacity is limited.Can cause the adhesion of conducting polymer and valve metal oxide-film or matrix solid electrolyte layer not strong simultaneously, and conducting polymer self structure is loose, cause the ESR of solid electrolytic capacitor to increase, later stage encapsulation process compressive property is poor, leakage current is bigger than normal, and high temperature examination reliability is poor.
[summary of the invention]
The technical problem to be solved in the present invention, the polymeric solution that provides a kind of solid electrolytic capacitor to prepare solid electrolyte layer, on the low side to solve solid electrolytic capacitor product capacity, ESR is higher, the bigger than normal and not good problem of high-temperature storage performance of leakage current value.
The technical problem to be solved in the present invention is achieved in that a kind of solid electrolytic capacitor prepares the polymeric solution of solid electrolyte layer, comprise conducting polymer monomer, dopant and solvent, it is characterized in that: also include performance improvement additives, this performance improvement additives is at least one in aliphatic ammonium salt, carboxylate, sulfuric acid, sulfonate, APES, fluoro-alkyl ether amine oxide, polyethylene glycol, crown ether, fluoro-alkyl APEO, and content is 0.001wt%～0.1wt%.
Further, described aliphatic ammonium salt comprises softex kw CTAB, DTAB, TTAB, Cetyltrimethylammonium bromide, two octyl dimethyl ammonium bromides, didecyl Dimethy ammonium bromide, didodecyldimethylammbromide bromide, DHAB, DDA, three-dodecyl methyl ammonium bromide, triethyl group methyl ammonium bromide, tripropyl methyl ammonium bromide, tributyl-methyl phosphonium ammonium bromide, trioctylphosphine methyl ammonium bromide, 4 bromide, TBAB, tetramethyl ammonium hydrogen sulfate, trioctylphosphine methylsulfuric acid ammonium, tetrabutylammonium iodide, trioctylphosphine methyl acid phosphate ammonium, DTAC, tetradecyl trimethyl ammonium chloride, hexadecyltrimethylammonium chloride, OTAC, two octyl alkyl dimethyl ammonium chlorides, didecyl Dimethy ammonium chloride, two dodecyl dimethyl ammonium chloride, Varisoft 432PPG, dioctadecyl dimethyl ammonium chloride, triethyl group ammonio methacrylate, tripropyl ammonio methacrylate, tributyl-methyl phosphonium ammonium chloride, tri-n-octyl methyl ammonium chloride, three-dodecyl methyl ammonium chloride, at least one of tetrabutylammonium chloride,
Described carboxylate comprises at least one of alcohol ether carboxylate, perfluoroalkyl ether carboxylate;
Described sulfuric acid comprises at least one of 1-methyl-3-alkyl imidazole sulfate, lauryl sulfate, alkylphenol ether sulfate, alkyl polyoxyethylene ether sulfate;
Described sulfonate comprises at least one of alkylsulfonate, fluoro-alkyl sulfonate, benzene sulfonate, fluorobenzene sulfonate, fluoro-alkyl benzene sulfonate, alkene sulfonate, sulfamate, benzene disulfonate, tosilate;
Described carboxylate, sulfuric acid, sulfonate are sodium salt, sylvite or ammonium salt.
The formula R of described APES-(C6H4)-O (C2H4O) nH, R is carbon number 8～12 alkyl, in molecule, the oxirane of addition is counted the integer of n=9～12;
Described crown ether comprises at least one of five crown ethers or six crown ethers;
The structural formula of described fluoro-alkyl APEO is Rf-O-(C2H4O) nH, and Rf is the fluorine-containing part substituting group of carbon number 8～12 or for perfluor substituting group, in molecule, the oxirane of addition is counted the integer of n=3～35.
Further, described polymeric solution is chemical polymerization solution or electrochemical polymerization solution, and described conducting polymer monomer is one or more in pyrroles, N-methylpyrrole, N-N-ethyl pyrrole N-, 3-caprylyl pyrroles; Described dopant is one or more in tosilate, dodecyl benzene sulfonate, dodecane sulfonate, naphthalene sulfonate, camsilate; Described solvent is water or organic solvent, or both mixtures.
Tool of the present invention has the following advantages: the present invention is adding performance improvement additives in polymeric solution, improve conducting polymer monomer and valve metal wettability, assist the process of regulation and control polymerization, impel synthetic conductive polymer coating even in valve metal surface distributed, film forming compact structure, and form stronger adhesion with valve metal, to improve electrical property and the reliability of capacitor.
[embodiment]
Following embodiment 1 to embodiment 3 is in solid aluminum electrolytic capacitor, utilizes chemical polymerization to prepare solid electrolyte layer.Chemical polymerization solution includes performance improvement additives, this performance improvement additives is at least one in aliphatic ammonium salt, carboxylate, sulfuric acid, sulfonate, APES, fluoro-alkyl ether amine oxide, polyethylene glycol, crown ether, fluoro-alkyl APEO, and content is 0.001wt%～0.1wt%.
Embodiment 1
To wrap salic 4VF aluminium foil (effective area 3.5mm * 4.0mm) immerses containing 1.8mol/L pyrrole monomer, 1.25mol/L p-methyl benzenesulfonic acid halo dopant, 5min in the chemical polymerization monomer solution of 0.001wt% performance improvement additives perfluoro octyl sulfonic acid potassium and water, takes out and dries 10min; Immersed again containing 5min in the chemical polymerization oxidation solution of 1.2mol/L potassium permanganate oxidant and water, take out and dry 10min; After repetition aforesaid operations 10 times, get final product to obtain solid electrolyte layer polypyrrole; At solid electrolyte layer outer surface, form successively carbon containing cathode layer, silver-contained cathode layer afterwards; Make monolithic capacitor element, by monolithic capacitor element stack encapsulation, make solid aluminum electrolytic capacitor.
Embodiment 2
Performance improvement additives in chemical polymerization monomer solution is 0.1wt% polyethylene glycol as different from Example 1.
Embodiment 3
Performance improvement additives in chemical polymerization monomer solution is 0.02wt% softex kw as different from Example 1.
Comparative example 1
As different from Example 1, in chemical polymerization monomer solution, do not contain performance improvement additives.
Following embodiment 4 to embodiment 10 is in solid aluminum electrolytic capacitor, utilize first chemical polymerization again electrochemical polymerization prepare solid electrolyte layer.Electrochemical polymerization solution of the present invention includes performance improvement additives, this performance improvement additives is at least one in aliphatic ammonium salt, carboxylate, sulfuric acid, sulfonate, APES, fluoro-alkyl ether amine oxide, polyethylene glycol, crown ether, fluoro-alkyl APEO, and content is 0.001wt%～0.1wt%.Chemical polymerization solution can comprise performance improvement additives, also can not comprise performance improvement additives.
Embodiment 4
To wrap salic 4VF aluminium foil (effective area 3.5mm * 4.0mm) immerses containing 1.8mol/L pyrrole monomer, 1.25mol/L p-methyl benzenesulfonic acid halo dopant, 5min in the monomer solution of 0.001wt% performance improvement additives perfluoro octyl sulfonic acid potassium and water, takes out and dries 10min.Immersed again containing 5min in the oxidation solution of 1.2mol/L potassium permanganate oxidant and water, take out and dry 10min; After repetition aforesaid operations 10 times, get final product to obtain the first solid electrolyte layer polypyrrole; The aluminium foil that comprises the first solid electrolyte layer polypyrrole is connected as anode with additional electrodes, take stainless steel as negative electrode, containing 0.4mol/L pyrrole monomer, 0.3mol/L p-methyl benzenesulfonic acid salt electrolyte, in the electrochemical polymerization solution of 0.1% performance improvement additives 18-crown ether-6 and water, carry out Galvanostatic polymerization 100min, current density is 3mA/cm2, then cleans and dry 15min, makes the second solid electrolyte layer polypyrrole.At the second solid electrolyte layer outer surface, form successively carbon containing cathode layer afterwards, silver-contained cathode layer, makes monolithic capacitor element, by monolithic capacitor element stack encapsulation, makes solid aluminum electrolytic capacitor.
Embodiment 5
In chemical polymerization monomer solution, do not comprise performance improvement additives as different from Example 4.
Embodiment 6
Performance improvement additives in electrochemical polymerization solution is 0.001wt% fluoro-alkyl ether amine oxide FC-8 as different from Example 4.
Embodiment 7
Performance improvement additives in electrochemical solution is 0.01wt% lauryl sodium sulfate SDS as different from Example 4.
Embodiment 8
Performance improvement additives in electrochemical solution is 0.01wt% perfluoroalkyl ethers carboxylic acid sylvite FC-5 as different from Example 4.
Embodiment 9
Performance improvement additives in electrochemical solution is 0.01wt% APES NP-10 as different from Example 4.
Embodiment 10
Performance improvement additives in electrochemical solution is 0.01wt% fluoro-alkyl polyoxyethylene ether FC-180 as different from Example 4.
Comparative example 2
As different from Example 4, in chemical polymerization monomer solution and in electrochemical polymerization solution, all do not contain performance improvement additives.
The various embodiments described above and comparative example are prepared into after 2V/220 μ F solid aluminum electrolytic capacitor, get 30 capacitor testing capacity, DF, ESR, leakage current value, and the ESR mean value after 105 ℃ of high temperature examination 1000h.Data are as shown in table 1.
The capacitor electrode Performance Ratio of table 1 embodiment and comparative example
As can be seen from Table 1, the capacity of the solid aluminum electrolytic capacitor that embodiment 1-10 is prepared with chemical polymerization solution of the present invention or electrochemical polymerization solution is compared with comparative example 1,2 improve 20-30%, and ESR and leakage current obviously reduce, and high temperature examination reliability level significantly improves simultaneously.