JPS59154767A - Organic electrolyte battery - Google Patents

Abstract

PURPOSE:To raise the thermal stability of an electrolyte as well as to aim at improvements in the capacity of an organic electrolyte battery, by using an electrolyte which dissolves a specified Li compound and BF3 in an organic solvent. CONSTITUTION:A halide of Li shown in a chemical formula LiX (X is of Cl, Br, I) is dissolved and dispersed in an organic solvent, and excessive BF3 is blown in this solution whereby LiX and BF3 are made into reaction. Next, the excessive BF3 is removed, adjusting an electrolyte. Using this electrolyte, an organic electrolyte batter including a button type one is assembled. This electrolyte is stable to heat and enjoys its conductivity. Therefore, an increase in internal resistance due to storage is as small as negligible as well as a drop in its discharging capacity is also little.

Description

[Detailed description of the invention] The present invention relates to organic electrolyte batteries.

Recently, lithium superborate, represented by LiBF4, has been used as an electrolyte for organic electrolyte batteries because it has good solubility in organic solvents, high conductivity, and is safer than perchlorate-based ones. It is attracting a lot of attention.

However, this LiBF4 lacks thermal stability and decomposes as shown in the following formula: LiBF4 → LiF + BF3 4 The lithium ion concentration in the electrolyte decreases, impairing its function as an electrolyte, and the decomposition products A certain BF5
reacts with the active material and electrolyte solvent, causing an increase in internal resistance and a decrease in discharge capacity, significantly deteriorating battery performance.

In view of such circumstances, the present inventors have conducted various studies and found that a compound represented by the general formula (I) Lix (I) (wherein, X is C1, Br and ■) is used as an electrolyte solvent. When dissolving LiX and BF3 in solution, LiX and B
It reacts with F3 and has high conductivity equivalent to LiBF4,
Furthermore, it was discovered that a substance more stable against heat than L 1BF4 was formed and could be suitably used as an electrolyte for organic electrolyte batteries, leading to the completion of the present invention.

Specific examples of the compound represented by the general formula (I) used in the present invention are LiC5, LiBr, and LiI. It is prepared by bubbling excess BFi into the liquid, causing Lqx and BF3 to react, and then removing excess BF. Also LiX
It is also possible to carry out the reaction of BF3 and BF3 in another solvent, precipitate the formed substance, and dissolve it in an electrolyte solvent separately.

In order to have a suitable function as an electrolyte, LiX should be 0.
．． It is preferable to use 2 to 8.0 mol/l, and A is LiX
generally have low solubility in organic solvents and initially do not dissolve in the required amount. Therefore, when LiX is saturated and dispersed in an organic solvent and BFg is blown into the liquid, LiX and BF5 react and LiX becomes dissolved in the liquid. At this time, 40
Heating to ~80°C is preferred because the reaction is accelerated. BF3 remaining in the solution is removed by, for example, reacting with the active material under heating, preferably at 60 to 80°C. Specifically, it will remain! It is preferable to remove 3F3 by alternately reacting a negative electrode active material such as lithium with a positive electrode active material such as titanium disulfide. Naori F3 was added to 1,2-dimethoxyethane (DME) (DMF,
) φBFg is commercially available, so instead of blowing F5 as described above, use it to saturate LiX.
You can also add it to the dispersed liquid.

Examples of organic solvents used as electrolyte solvents in the present invention include 1,3-dioquinrane, 4-methyl-1,8
-Dioxolane, 1,2-dimethoxyethane, propylene carbonate, tetrahydrofuran, 2-methyltetrahydrofuran, r-butyrolactone, ethylene glycol diethyl ether, 4,4-dimethyl-1,3-dioquinrane, 4,5-dimethyl-1,3 -dioxolane, acetonitrile, CH3PCI2, C2H3PC12
, CH50PC12, (C6H5)2・PCI, 12-
Crown-4 (114+7110-tetraoxacyclododecane (1*4+L10- Tetraoxa
cyclod.

Decane ) ), 15-Crown 5 (
L44+10s18-pentaoxacyclopentadecane (1,4,7,10,18-1'entaoxacyc
lopentadecane)), 1B-Cro
wn-6(1,4,7,10,18,16-hexaoxacyclooctadecane(1eCLILIL16-He
Examples of solvents include cracked ethers such as xaoxacyclooctadecane) or a mixture of two or more thereof.

Examples of negative electrode active materials include lithium, lithium alloys of lithium and aluminum, mercury, zinc, and cadmium, sodium, magnesium, and aluminum; examples of positive electrode active materials include titanium disulfide,
Iron disulfide, ferrous sulfide and other iron sulfides, manganese dioxide,
Carbon heptides such as (CF)n and (C2F)n, niobium disulfide, V601s, Cu5.v201o, etc. are used.

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

Example 1 LiC1 was added to a mixed solvent of 4-methyl-1,3-dioxolane and 1,2-dimethoxyethane in a volume ratio of 7-8.
．． While adding 5 mol/l, dispersing and heating to 60'C,
BF5 was blown into this liquid, and the BF5 injection was stopped when LiCl was dissolved. Then, heat this liquid at 60°
While heating to C, the liquid is passed alternately through a column filled with lithium and a column filled with titanium disulfide, and BF3 remaining in the solution is removed by reacting alternately with lithium and titanium disulfide, forming an organic electrolyte. A system electrolyte was prepared.

Using this electrolyte, lithium was used as the negative electrode active material, titanium disulfide was used as the positive electrode active material, and a layer made of a microporous polypropylene film and a polypropylene nonwoven fabric was used as the layer. A similar button-shaped organic electrolyte battery was assembled. The amount of titanium subsulfide used is 1
It was Cape 00.

Example 2 1.5 LiCl in 4-methyl-1,8-dioxolane
Mol/1 Ffa was added and dispersed, and an adduct of 1,2-dimethoxyethane and BF5 was added to this liquid while heating at 60°C until LiC1 was dissolved. Next, in the same manner as in Example 1, BF3 remaining in the solution was removed by treatment with lithium and titanium disulfide to prepare an electrolytic solution.

A button-shaped organic electrolyte battery was assembled using this electrolyte in the same manner as in Example 1. , Comparative Example 4 - I, 1BFJ was added to a mixed solvent of methyl-1,8-dioxolane and 1,2-dimethoxyethane in a volume ratio of 7-3.
A button-shaped organic electrolyte battery was produced in the same manner as in Example 1, except that an electrolyte solution containing 1.5 mol/l of 1.

Initial resistance and internal resistance of the batteries of Examples 1 and 2 and the batteries of Comparative Example and after storage at 60°C for 40 days and 20°
Discharge fc to the final voltage of 1.5V through C1 resistor 10Ω
Table G61 shows the results of the investigation of the discharge capacity of H.

Table 1 v: As shown in Table 1, the battery of the present invention has less internal resistance increase due to storage than the conventional battery shown in the comparative example, and the discharge capacity also decreases rapidly.Patent Applicant: Hitachi Maxell, Ltd.

Claims (1)

[Scope of Claims] (2) Using an electrolytic solution prepared by dissolving a compound represented by the general formula (I) LiX (I) (in the formula, Xf-jcl, Br or I) and BFg in an organic solvent. An organic electrolyte battery featuring seven features.