JPS631018A - Electrolyte for capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of Application According to the present invention, an excellent electrolytic solution for capacitors (hereinafter sometimes simply referred to as electrolytic solution) with high conductive dust can be obtained.

[Prior art] The characteristics of a capacitor are determined by various factors, but in particular the characteristics of the electrolyte that is housed in the outer case together with the capacitor element have a large effect on impedance or equivalent series resistance (ESR). It has been found that

For example, low-voltage electrolytic capacitors use an electrolytic solution in which a triethylamine salt of maleic acid or the like is dissolved in a γ-butyrolactone solvent.

Problems to be Solved by the Invention However, as the frequency of switching regulators has increased in recent years, capacitors with lower impedance or lower equivalent series resistance are required, and the development of electrolytes with high conductivity is desired.

Means to Solve the Problems The present inventors conducted intensive studies to find an electrolytic solution with high conductive dust, and found that a quaternary phosphonium salt of carbonic acid exhibits high conductive dust, and completed the present invention.

That is, the present invention provides an electrolytic solution for a capacitor characterized by using a quaternary phosphonium salt of carbonic acid as a solute.

Detailed Description of the Invention In the present invention, the quaternary phosphonium salts of carbonic acid used as solutes include tetramethylphosphonium, tetraetherphosphonium, tetrapropylphosphonium, tetrabutylphosphonium,
methyl) IJ ethylphosphonium, methyltriglobylphosphonium, methyltributylphosphonium, dimethyldiethylphosphonium, dimethyldipropylphosphonium, dimethyldibutylphosphonium, trimethylethylphosphonium, trimethylpropylphosphonium,
Aliphatic quaternary phosphoniums such as trimethylbutylphosphonium, ethyltriflobylphosphonium, ethyltributylphosphonium, dimethyldipropylphosphonium, diethyldibutylphosphonium, triethylbutylphosphonium, triethylbutylphosphonium, propyltributylphosphonium, diethyldibutylphosphonium, tripropylbutylphosphonium, etc. salts and 1,1-dimethylphosphoranium, 1-methyl-1-ethylphosphoranium, 1,1-diethylphosphoranium, 1,1-
Diethylphosphoranium, 1-methyl-1-ethylphosphoranium, 1,1-diethylphosphoranium, 1,1
-Alicyclic quaternary phosphonium salts such as bentamethylene phosphorinium can be exemplified.

Examples of the τ medium for dissolving the quaternary phosphonium salt of carbonic acid of the present invention include N-methylformamide, N-ethylformamide, N,N-dimethylformamide, N,N-diethylformamide, N-methylacetamide, and N-ethylacetamide. , N, N-dimethylacetamide, N, N
- Amide solvents such as diethylacetamide and N-methylpyrrolidinone, lactone solvents such as γ-butyrolactone, γ-valerolactone, and δ-valerolactone, carbonate solvents such as ethylene carbonate, propylene carbonate, butylene carbonate, ethylene glycol, chrycerin, methyl Examples include alcohol solvents such as celonorb, nitrile solvents such as 3-methoxypropionitrile, and phosphoric acid ester solvents such as trimethyl phosphate, alone or in combination. Among these, γ
- A solvent mainly composed of butyrolactone is particularly preferable because it has low toxicity and is less likely to attack capacitor sealants or contain halogens.

The amount of the quaternary phosphonium salt of carbonic acid dissolved in the above solvent is below the saturation concentration, preferably 5 to 40% by weight.

However, the dissolved salt in the electrolytic solution may be a neutral salt or an acidic salt.

The electrolytic solution of the present invention essentially consists of a quaternary phosphonium salt of carbonic acid and a solvent, but has the following properties: prevention of galvanic corrosion, reduction of leakage current, etc.
Small amounts of co-solutes may be added for various purposes.

Effects of the Invention The quaternary phosphonium salt of carbonic acid used as a solute in the present invention has good solubility in solvents, and its electrolyte exhibits high conductivity. This is a wide range of capacitor solution.

EXPERIMENTAL EXAMPLES The present invention will be explained in more detail below with reference to Examples and Comparative Examples.

Example 1 An electrolytic solution was obtained by dissolving 20% by weight of tetraethylphosphonium carbonate in a γ-butyrolactone solvent. The iπ conductivity of this electrolyte at 25°C is 8.3 mS/cl.
n, and 4 m on 1 set of + and -1 aluminum smooth foils.
The spark generation voltage when constant current was applied to A and Z was 208V.

Example 2 In Example 1, an electrolytic solution was prepared using N,N-dimethylformamide solvent instead of the γ-butyrolactone solvent.

Example 3 In Example 1, an electrolytic solution was prepared using tetrabutylphosphonium carbonate instead of tetraethylphosphonium carbonate.

Example 4 Similar to Example 3, an electrolytic solution was prepared using a propylene carbonate solvent instead of the γ-butyrolactone solvent.

Comparative Example In Example 1, an electrolytic solution was prepared using triethylamine salt of maleic acid instead of tetraetherphosphonium carbonate salt.

The electrical conductivity and spark generation pressure of these electrolytes are shown in Table 1. In Table 1, the following abbreviations were used.

GBL: γ-butyrolactone DMF: N,N-dimethylformamide PC: Propylene carbonate Table 1

Claims (1)

[Claims] An electrolytic solution for capacitors characterized by using a quaternary phosphonium salt of carbonic acid as a solute.