JPH0329286B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an electrolytic solution for electrolytic capacitors containing a fluorocomplex salt of a pyrrolidine or N-methylpyrrolidine compound as an electrolyte in an aprotic solvent. [Prior Art] Traditionally, organic acids or their salts/glycol-based pastes have been mainly used as electrolytes for electrolytic capacitors for normal purposes, but due to the recent increase in the range of use of electronic devices, improvements in capacitor performance have been required. As demands for improvements have increased, the presence of water in pastes has become a major problem, and electrolytic solutions that use aprotic solvents to replace organic acids or their salts/glycol pastes are attracting attention. However, the biggest problem with aprotic solvent-based electrolytes is how to obtain electrolytes with high conductivity. The search for organic carboxylic acids or their salts has been the main focus, but this goal has not yet been achieved. Although attempts are still being made to obtain high conductivity by combining solvents that react with acids such as alcohols and glycols to produce water, and even water in aprotic solvents, it is not possible to achieve sufficiently high conductivity. The current situation is that it suffers from a lack of stability at high temperatures due to an increase in the amount of water and electrolyte. It is therefore an object of the present invention to provide a substantially non-aqueous high conductivity electrolyte for use with an aprotic solvent. [Problems to be Solved by the Invention] The present inventors have solved the problem by using an aprotic solvent and without using a solvent that reacts with acids such as alcohols and glycols to produce water. As a result of extensive research into an aqueous electrolyte that provides high conductivity, we found that salts of fluorocomplex acids with pyrrolidine or N-methylpyrrolidine compounds have high solubility in aprotic solvents and have a high degree of dissociation. The present invention was achieved by discovering that electrical conductivity can be imparted. That is, the electrolytic solution for electrolytic capacitors according to the present invention has the general formula (In the formula, R = H or 1 to 2 methyl groups, the nitrogen atom constitutes a secondary, tertiary or quaternary amine, A
= fluorocomplex acid) containing a fluorocomplex salt of a pyrrolidine or N-methylpyrrolidine compound as an electrolyte. Examples of the pyrrolidine to N-methylpyrrolidine compounds to be used in the present invention include pyrrolidine tetrafluoroborate, N-methylpyrrolidine tetrafluoroborate, N,N-dimethylpyrrolidinium tetrafluoroborate, and pyrrolidine hexafluoroborate. Examples include phosphate, N-methylpyrrolidine hexafluorophosphate, and N,N-dimethylpyrrolidinium hexafluorophosphate. The aprotic solvents used include (1) amide solvents N-methylformamide, N,N-dimethylformamide, N-ethylformamide, N,N
-Diethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-ethylacetamide, N,N-diethylacetamide, hexamethylphosphorinamide (2) Oxide dimethyl sulfoxide (3) Nitrile acetonitrile (4) Representative examples include cyclic ester, amide type γ-butyrolactone, N-methyl-2-pyrrolidone ethylene carbonate, propylene carbonate, etc., but are not limited thereto. The fluoro complex acids targeted by the present invention are tetrafluoroboric acid (HBF ₄ ) and hexafluorophosphoric acid (HPF ₆ ). The electrolytic solution for an electrolytic capacitor according to the present invention is generally prepared by adding an equivalent amount of a desired pyrrolidine or N-methylpyrrolidine compound to an aqueous solution of a fluorocomplex acid, followed by drying under reduced pressure to obtain an anhydrous salt. It can be adjusted to a concentration that provides the desired degree of strength. [Example] Table 1 below shows the conductivities of 10% by weight solutions of various pyrrolidine compound fluorocomplex salts in various aprotic solvents for examples of electrolytic solutions for electrolytic capacitors according to the present invention. As a comparative example, a conventional standard electrolytic solution (78% by weight of ethylene glycol, 12% of water, 10% of ammonium adipate) is shown.

【table】

[Table] Next, Table 2 shows the results of a high temperature load test at 16V 1000μF for the electrolytes of Examples 1 to 6 and Comparative Example.

〔Effect of the invention〕

According to the electrolytic solution of the present invention, it is possible to provide a non-aqueous electrolytic solution having a high conductivity comparable to or higher than that of conventional glycols, water, and organic acid salts, and is suitable for use in the design field of electrolytic capacitors. provides a new and wide range of performance options.

Claims (1)

[Claims] 1. General formula in an aprotic solvent (In the formula, R = H or 1 to 2 methyl groups, the nitrogen atom constitutes a secondary, tertiary or quaternary amine, A
= fluoro complex acid) pyrrolidine to N-
An electrolytic solution for electrolytic capacitors containing a fluorocomplex acid of a methylpyrrolidine compound as an electrolyte. 2 The aprotic solvent is N-methylformamide,
N,N-dimethylformamide, N-ethylformamide, N,N-diethylformamide, N-
Methylacetamide, N,N-dimethylacetamide, N-ethylacetamide, N,N-diethylacetamide, γ-butyrolactone, N-methyl-2-pyrrolidone, ethylene carbonate, propylene carbonate, dimethylsulfoxide, acetonitrile or mixtures thereof An electrolytic solution for an electrolytic capacitor according to claim 1, which is selected from the group of: 3. The electrolytic solution for an electrolytic capacitor according to claim 1 or 2, wherein the fluoro complex acid is tetrafluoroboric acid or hexafluorophosphoric acid.