JPH0528443B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a solid polymer electrolyte and a battery using the same.

Prior Art and Its Problems In recent years, research on solid polymer electrolytes has been actively conducted with the aim of applying them to display elements, batteries, and the like.

For example, when applied to a lithium battery, the solid polymer electrolyte is used by being placed between the positive electrode part and the negative lithium part and/or by being filled in the pores of a microporous electrode. Types of solid polymer electrolytes include polyphosphazene, polyethylene oxide,
Many systems have been proposed, including polyamino acid systems.
However, materials with good ionic conductivity and strength that can withstand handling usually have an active moiety in their molecular structure, and are used as battery active materials, especially metallic lithium as cathode active materials, or By continuing contact with the positive electrode active material (including additives), etc. for a long time, the active part (hydrogen or halogen at a specific position) in the polymer solid electrolyte molecules reacts with lithium, etc., and the polymer solid electrolyte Altered and deteriorated. Active hydrogen is, for example, H of the -OH group that reacts directly with alkali metals or alkaline earth metals or their ions, and H of -NH- group, and active halogen is, for example, H of -CH ₂ Cl.
It is Cl.

For example, a polyether solid electrolyte crosslinked with isocyanate has a crosslinked portion represented by -NHCOO-. When the solid electrolyte continues to be in contact with lithium for a long period of time, lithium atoms are captured by the hydrogen in -NHCOO-, causing decomposition and side reactions. This inhibits normal electrode reactions in the battery system. When such a solid electrolyte is used as it is in a lithium battery, there is a problem in that the internal resistance increases and the battery capacity decreases significantly.

Purpose of the Invention The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a solid polymer electrolyte that does not deteriorate during long-term storage and a solid polymer electrolyte battery using the same that does not deteriorate in performance.

Composition of the Invention In order to achieve the above object, the present invention provides a solid polymer electrolyte containing active hydrogen or halogen in its molecular structure that directly reacts with alkali metals or alkaline earth metals or their ions. Alternatively, it is a polymer solid electrolyte characterized by adding a substance that can replace halogen with another inert group.

Furthermore, in polymer solid electrolytes that contain active hydrogen or halogen in their molecular structure that directly reacts with alkali metals or alkaline earth metals or their ions, these active hydrogens or halogens can be combined with other inert groups. It is also possible to use a solid polymer electrolyte that is characterized by being substituted in advance.

Polymer solid electrolyte containing active hydrogen or halogen that reacts directly with alkali metals or alkaline earth metals or their ions in its molecular structure, with active hydrogen or halogen being replaced with other inactive groups. This is a battery using a solid polymer electrolyte, characterized in that it is used as an ion conductive medium between negative and positive electrodes.

That is, by inactivating the active hydrogen contained in the solid electrolyte structure as described above by various methods, it is possible to provide a polymer solid electrolyte that does not deteriorate during long-term storage. Typical inert treatment methods include alkylation and acylation. alkylation,
A method that uses a polymer solid electrolyte added with an acylating agent to prevent substitution reactions with metallic lithium, or an inactivation treatment in the post-process of polymer solid electrolyte production to inactivate the active portion in advance. You can choose a method such as replacing it in a group and then assembling it into a product.

For example, polyamine-based polymer solid electrolytes It has a structure like this, but here the hydrogen of the -NH- group is susceptible to a substitution reaction with lithium etc. Therefore, by adding an alkyl halide such as methyl iodide to this electrolyte, when a metal ion attempts to attack the hydrogen of the -NH- group, the alkyl moiety of the alkyl halide immediately replaces the hydrogen. Substitution reactions with lithium etc. are prevented.

-NH-+MRX ---→ [-NM-]RX ----→ -NR- Here, M represents a metal, R represents an alkyl group, and X represents a halogen.

Furthermore, by adding an acylating agent such as acetic anhydride to the same electrolyte, substitution reaction with metals can be prevented by a similar mechanism.

−NH−+MCH ₃ COR′ ———→ [−NM−]CH ₃ COR′ ———→ −NCOCH ₃ − Alternatively, the electrolyte may be treated with an alkyl metal such as butyllithium and then treated with iodine. If alkylated with an alkyl halide such as methyl chloride, a solid polymer electrolyte that is inert to lithium or the like can be obtained.

-NH-+RM→-NM-+RH -NM-+RM→-NR-+MX Also, if treated with an acetylating agent such as acetyl chloride, a similarly inert polymeric solid electrolyte can be obtained.

-NH-+ _CH3COX → _-NCOCH3- +HX Examples The details of the present invention will be explained with reference to Examples.

Example 1 Triol-type trifunctional polyale (molecular weight
3000), 1 part of methyl iodide, 1 part of dimethylformamide, an equivalent amount of hexamethylene diisocyanate, and a trace amount of Di-n-butyltin diacetate, mixed thoroughly, and then applied to a fabric support. , an electrolyte sheet was obtained by crosslinking in an inert gas at 80°C.

Next, 4 parts of vanadium pentoxide, 1 part of acetylene black, 5 parts of triol type trifunctional polyether in which 9 wt% lithium perchlorate was dissolved in advance, 1 part of dimethylformamide, an equivalent amount of hexamethylene diisocyanate, and a trace amount Di-n-
A finely kneaded mixture of butyltin diacetate was applied to the upper surface of the sheet and solidified in an inert gas at 80°C. After drying the sheet, a pellet was cut out, metal lithium was attached, and the pellet was placed in a mechanically sealed container to prepare a battery.

The above batteries were stored at 80° C. for various days and their internal resistance and discharge capacity were examined. Figure 1 shows the results of a comparison with a conventional battery containing no methyl iodide.

Example 2 Triol-type trifunctional polyether (molecular weight
3000) 5 parts, 1 part of dimethylformamide, an equivalent amount of hexamethylene diisocyanate and a trace amount of Di
-n-Butyltin diacetate was added and thoroughly mixed, then coated on a fabric support and crosslinked in an inert gas at 80°C to obtain an electrolyte sheet.

Next, the sheet was immersed for 3 hours in a solution prepared by diluting a commercially available n-butyllithium n-hexane solution 20 times with n-hexane. After sufficiently removing the immersion liquid, methyl iodide was transferred to a solution diluted with n-hexane, immersed for 3 hours, and then vacuum dried at 80°C.

Next, 4 parts of vanadium pentoxide, 1 part of acetylene black, 5 parts of triol type trifunctional polyether in which 9 wt% lithium perchlorate was dissolved in advance, 1 part of dimethylformamide, an equivalent amount of hexamethylene diisocyanate, and a trace amount Di-n-
A well-kneaded mixture of butyltin diacetate was applied to the top surface of the sheet and solidified in an inert gas at 80°C.

After drying the above sheet, cut it into pellets,
Metal lithium was attached and assembled into a hermetically sealed container to form a battery.

This battery was stored at 80° C. for various days, and its internal resistance and discharge capacity were examined.

The results were almost as effective as in Example 1. In both cases, the effect of preventing performance deterioration due to high temperature storage was extremely significant.

Effects of the Invention As described above, the present invention can provide a solid polymer electrolyte that does not deteriorate during long-term storage and a solid polymer electrolyte battery that does not deteriorate in performance using the same, so its industrial value is extremely large. be.

[Brief explanation of the drawing]

FIG. 1 is a diagram comparing the performance of the battery of the present invention and a conventional product.

Claims (1)

[Scope of Claims] 1. In a solid polymer electrolyte that contains active hydrogen or halogen in its molecular structure that directly reacts with alkali metals or alkaline earth metals or their ions, the active hydrogen or halogen is replaced with an inert one. A solid polymer electrolyte characterized by the addition of a substance that can replace other groups. 2. In a solid polymer electrolyte containing active hydrogen or halogen in its molecular structure that directly reacts with alkali metals or alkaline earth metals or their ions, those active hydrogens or halogens are replaced in advance with other inactive groups. A polymer solid electrolyte that is characterized by: 3 A polymer solid in which the active hydrogen or halogen of a polymer solid electrolyte containing active hydrogen or halogen that reacts directly with alkali metals or alkaline earth metals or their ions in its molecular structure has been replaced with other inactive groups. A battery using a solid polymer electrolyte, characterized in that the electrolyte is used as an ion conductive medium between negative and positive electrodes.