JPS6023973A - Organic electrolyte battery - Google Patents

Abstract

PURPOSE:To provide an organic electrolyte battery having excellent heavy-load characteristic, low-temperature characteristic and preservation stability by using a phosphoric triester as an electrolyte solvent. CONSTITUTION:Either a phosphoric triester along or mixture of two or more phosphoric triesters can be used as an electrolyte solvent in an organic electrolyte battery. Compounds such as (CH3O)3P=O, (C2H5O)3P=O, (C3H7O)3P=O, (C4H9O)3P=O, (C8H17O)3P=O, (ClCH2CH2O)3P=O, (Cl2C3 H5O)3P=O, (C6H5O)3 P=O and (CH3C6H4O)3P=O are listed as phosphoric triesters. By using such phosphoric triesters as electrolyte solvents, decomposition of a super-acid-system electrolyte such as LiPF6, LiBF4, LiAsF6 or LiSbF6 is suppressed increasing the stability of electrolyte thereby improving the storage stbility of the battery. In such a battery, the characteristics of the super-acid-system electrolyte such as a high solubility in the solvent, a high conductivity and a higher stability than that of a perchlorate system compound can effectively be exhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION An object of the present invention is to provide an organic electrolyte battery having excellent heavy load characteristics, low temperature characteristics, and storage stability by using a realester as an electrolyte solvent.

Conventionally, electrolytes for organic electrolyte secondary batteries that use lithium or lithium alloy as a negative electrode active material include lithium perchlorate dissolved in a mixed solvent of propylene carbonate and 1,2-dimethoxyethane, and lithium perchlorate. 1
．． one dissolved in a mixed solvent of 3-dioxolane and 1,2-dimethoxyethane, one in which lithium perchlorate was dissolved in a mixed solvent of T-butyrolactone and 1,2-dimethoxyethane, or 1. , iBF4 dissolved in a mixed solvent of T-butyrolactone and 1,2-dimethoxyethane has been used. Also, l, iPF6 is 1,
LiPF6 dissolved in a mixed solvent of 3-dioxolane and 1,2-dimethoxyethane was dissolved in 4-methyl-1,3
- LiB(C6HS)4 dissolved in a mixed solvent of dioxolane and 1,2-dimethoxyethane, and 1
．． Electrolytes dissolved in a mixed solvent of 3-dioxolane and 1,2-dimethoxyethane are also being considered as electrolytes, but these have problems in terms of performance under heavy loads, low-temperature characteristics, thermal stability, and safety. However, the results were not necessarily satisfactory.

In view of these circumstances, the present inventors have conducted various studies and found that, in an organic electrolyte battery that uses lithium or lithium alloy as the negative electrode active material, a lithium salt is used as the electrolyte and a phosphoric acid triester is used as the electrolyte solvent. At that time, it was discovered that an organic electrolyte battery with excellent heavy load characteristics, low temperature characteristics, and storage stability could be obtained, and the present invention was completed.

In the present invention, examples of lithium salts used as electrolytes include Li CI 04, LiPF5, LiB
F4, LiAsF6, Li5bFs, LiAIc14
・LiB10C110・LiB12C1+
z, LiB (C6H5)4, LiB (p-FCs
Examples include H4)3CH3 and LjB (p-FC6H4)4.

As the phosphoric acid triester, for example, (CH30)3P
=O1(C2H50)3 P=O,(C3H70)3
P=O1(C4)IsO) 3P=O.

(C8HI70)3 P=O1(CI CH2CH20
)3P=O1(CI2 C3H50)3P=O1(C
s Hs O)3 P-0, (CH3Cs H40)'
Examples include 3P=O, and these can be used alone or in combination of two or more. In particular, (CH30)3
P=O1(C2H50)3 P=O,(C4H90)
3 P=O1 (CB HI70) 3 P=0, (CI
CH2CH20)3 P=O and the like are easily available and are preferably used. When these phosphoric acid triesters are used as electrolyte solvents, l, 1PF6, 'LiBF4, Li
The decomposition of superacid electrolytes such as AsF6 and Li5bF is suppressed, the stability of the electrolyte is increased, and the storage stability of the battery is improved. It is particularly effective when using these superacid-based electrolytes because they can effectively exhibit properties such as conductivity and higher safety than perchloric acid-based electrolytes.

The above phosphoric acid triester can be used alone as an electrolyte solvent, but it can also be used in combination with other organic solvents. Other organic solvents used in this case include, for example, 1,2-dimethoxyethane, 1,2-jethoxyethane, propylene carbonate, γ-butyrolactone, tetrahydrofuran, 2-methyl-tetrahydrofuran,
．． 3-dioxolane, 4-methyl-1,3-dioxolane, 4,4-dimethyl-1,3-dioxolane, 4.5
-dimethyl-1,3-dioxolane, 2-methyl-1,
Examples include 3-dioxolane and 2,4-dimethyl-1,3-dioxolane. The mixing ratio of the phosphoric triester and these organic solvents depends on the concentration of the electrolyte, but it is preferable that the phosphoric triester is 5% by volume or more in the mixed solvent.

The electrolytic solution is prepared by dissolving the lithium salt as the electrolyte in a phosphoric triester or a mixed solvent of a phosphoric triester and another organic solvent, and the concentration of the lithium salt in this electrolytic solution is 0.1 to 3. It is preferable to set it to .0 mol/β.

In the organic electrolyte battery of the present invention, the negative electrode active material includes:
Lithium, lithium with lithium such as aluminum, mercury, zinc, cadmium, etc. Iron sulfides such as titanium disulfide, iron disulfide, ferrous sulfide, ferric sulfide, manganese dioxide, (CF), (CF) χ fluorinated carbons such as
Niobium disulfide, V6O13, Cu5V2010, etc. are used.

Next, the present invention will be explained with reference to Examples.

Example 1 1.1PF6 with (CH30)3P=O and 4-methyl-
An electrolytic solution consisting of an organic electrolyte was prepared by dissolving it in a mixed solvent with a volume ratio of 3077'O to 1,3-dioxolane at a ratio of 1.5 mol/β, and a button type battery was manufactured using this electrolytic solution. Manufactured. The battery consists of a lithium metal negative electrode and a titanium disulfide mixture with titanium disulfide as the positive electrode active material.
A stack of microporous polypropylene film and polypropylene nonwoven fabric was used as the separator. Note that the separator was a microporous polypropylene film arranged so as to face the lithium negative electrode.

Example 2 A button-shaped cell was prepared in the same manner as in Example 1, except that the electrolyte solvent was replaced with a mixed solvent of (C2H50)'3p=0 and 4-methyl-1,3-dioxolane in a volume ratio of 30:70. Manufactured a battery.

Example 3 A button-shaped battery was produced in the same manner as in Example 1, except that the electrolyte solvent was replaced with a mixed solvent of (C4HsO)3P-0 and propylene carbonate in a volume ratio of 30:70.

Example 4 Electrolyte solvent (CB HI70)3 P=O and 1,2-
A button-shaped battery was produced in the same manner as in Example 1, except that a mixed solvent with dimethoxyethane and dimethoxyethane at a volume ratio of 50:50 was used.

Example 5 As an electrolyte solvent (CI CH2CI(20) 3P
= The volume ratio of 0 and 1,2-dimethoxyethane is 50:5
A button-shaped battery was produced in the same manner as in Example 1, except that the mixed solvent of 0 was used.

Example 6 As electrolyte solvent 7 (C2HsO)3P-,O
A button-shaped battery was manufactured in the same manner as in Example 1 except that the following was used alone.

Comparative Example 1 A button-shaped battery was manufactured in the same manner as in Example 1, except that a mixed solvent of propylene carbonate and 1,2-dimethoxyethane with a volume ratio of 70:30 was used as the electrolyte solvent.

Examples 1 to 6 and Comparative Example 1 obtained as above
battery initial and 1kHz after 40 days storage at 60”c
Table 1 shows the results of measuring the z impedance. In addition, the O”c and closed circuit voltage (2
(measured after discharging at Ω for 5 seconds) The results are shown in Table 2.

Table 1 Table 2 As shown in Table 1, the batteries of Examples 1 to 6 showed less increase in internal resistance due to storage compared to the battery of Comparative Example 1, and as shown in Table 2, It has excellent characteristics.

Claims (3)

[Claims] (1) An organic electrolyte battery using lithium or a lithium alloy as a negative electrode active material, characterized in that a lithium salt is used as the electrolyte and a phosphoric acid triester is used as the electrolyte solvent. (2) Lithium salt is LiPF6, LiAsF6, L
The organic electrolyte battery according to claim 1, which is iSbF6 or LiBF4. (3) Phosphoric acid triester is (CH30)3 P=0, (
(,2Hs O)3 P=O1(C4H90,) 3p
=o, (C8HI70) 3 P=O or (CICH
The organic electrolyte battery according to claim 1 or 2, wherein 2CH20)3P=O.