JPS6314417A - 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 conductivity can be obtained.

Conventional technology and problems 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 is clear that

For example, electrolytic capacitors have traditionally used ethylene glycol-ammonium adipate-based electrolytes. 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 higher conductivity is desired.

Means for Solving the Problem The present inventors conducted extensive studies to find an electrolytic solution with high conductivity, using quaternary phosphonium ions as a cationic component, CF35Os-, CtOa-, and PF5-.

The present invention was completed based on the discovery that a salt consisting of at least one anion component selected from AsFr>- and 5bFa- exhibits high fundamental conductivity.

That is, the present invention uses quaternary phosphonium ions as cation components, CFs SO3-, , CI, 04- + PFa
−.

The present invention provides an electrolytic solution for a capacitor, which is characterized in that it is used in the summer using a salt consisting of at least one anion component selected from AsF5- and 5bFa- as a solute.

DETAILED DESCRIPTION OF THE INVENTION The solute used in the present invention has a quaternary phosphonium ion as a cationic component, and is CFa SO3−+Cl
O4−+ PFa″″, AsF6″″ and 3bF
It is a salt consisting of at least one anion component selected from a-.

Quaternary phosphonium ions of cationic components include tetramethylphosphonium, tetraethelphosphonium, tetrapropylphosphonium, tetrabutylphosphonium, methyltriethylphosphonium, methyltripropylphosphonium, methyltributylphosphonium, dimethyldiethylphosphonium, dimethyldipropylphosphonium, dimethyldibutyl Phosphonium, trimethylethylphosphonium, triethylpropylphosphonium, trimethylbutylphosphonium, ethyltripropylphosphonium, ethyltributylphosphonium, diethyldipropylphosphonium, dimethyldibutylphosphonium, triethylpropylphosphonium, triethylbutylphosphonium, propyltributylphosphonium, dipropyldibutylphosphonium, Aliphatic quaternary phosphonium ions such as propylbutylphosphonium and 1
．． 1-dimethylphosphoranium, 1-methyl-1-ethylphosphoranium, 1,1-diethylphosphoranium,
Examples of alicyclic quaternary phosphoranium ions include 1,1-diethylphosphoranium, 1-methyl-1-ethylphosphoranium, 1.1-diethylphosphoranium, and 1.1-pentamethylenephosphoranium. be able to.

Examples of the solvent for dissolving the solute of the present invention include N-methylformamide, N-ethylformamide, N,N-dimethylformamide, N,N-diethylformamide, N-
Methylacetamide, N-ethylacetamide, N, N
- Amide solvents such as dimethylacetamide, N,N-diethylacetamide, N-methylpyrrolidinone, lactone solvents such as r-butyrolactone, γ-valerolactone, δ-valerolactone, carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, etc. )
? Examples include solvents such as I solvent, alcohols such as ethylene glycol, glycerin, and methyl cellosolve, nitrile solvents such as 3-methoxypropionitrile, and phosphate ester solvents such as trimethyl phosphate, alone or in combination. Among these, a solvent mainly composed of T-butyrolactone is particularly preferred because it has low toxicity and is less likely to attack the capacitor sealant or be contaminated with halogen.

The amount of the solute of the present invention dissolved in the above solvent is below the incubation concentration, preferably 5 to 40% by weight5.

The electrolytic solution of the present invention essentially contains quaternary phosphonium ions as a cationic component, CFaSO3-tCLOa-,
It consists of a salt solute and a solvent consisting of at least one anion component selected from PFs"", AsF6"" and 3bFs"", and a small amount of auxiliary material may be used for various purposes such as preventing galvanic corrosion and reducing leakage current. There is no problem in adding a solute.

Effects of the Invention The solute used in the present invention has good solubility in a solvent, and the electrolyte thereof exhibits high conductivity. By using it together with a solvent with a wide range of freezing point to boiling point, an electrolyte for capacitors can be used over a wide temperature range. becomes.

Experimental example EXAMPLES The present invention will be explained in more detail with reference to Examples below.

Example 1 An electrolytic solution was obtained by dissolving 20% by weight of antimony tetraetherphosphonium fluoride in a T-butyrolactone solvent. The conductivity of this electrolyte at 25°C is 12.0 mS/c
It was 1n. Also, + to this electrolyte.

- A set of aluminum smooth foils was immersed and a constant flow of 4 mφ was applied to form an oxide film on the anode.

The voltage reached at this time was 270V.

Examples 2 to 4 In Example 1, tetraethylphosphonium fluoride (tetraethylphosphonium fluoride) was used instead of tetraethylphosphonium antimony fluoride.
Table 1 shows the conductivities of the electrolytes using Example 2), tetraethylphosphonium perchlorate (Example 9133), and tetraethylphosphonium tetrafluoromethanesulfonate (Example 4).

Example 5.6 In Example 4, the conductivity of the electrolyte using N,N-dimethylformamide solvent (Example 5) and propylene carbonate solvent (Example 6) instead of the γ-butytetralactone solvent was evaluated. It is shown in Table 1.

In Table 1, the following abbreviations were used.

GBL: γ-butyrolactone DMF: N,N-dimethylformamide PC: Propylene carbonate (blank below) Table 1

Claims (1)

[Claims] Using quaternary phosphonium ion as a cation component, CF_
3SO_3^-, ClO_4^-, PF_6^-, As
An electrolytic solution for a capacitor, characterized in that a salt consisting of at least one anion component selected from F_6^- and SbF_6^- is used as a solute.