JPH01227365A - Polymer solid electrolyte and polymer solid electrolyte storage battery - Google Patents

Abstract

PURPOSE:To prevent the deterioration of battery capacity owing to the repeating charge and discharge of a storage battery using a polymer solid electrolyte by adding a specific times of amount of substance including at least one radical of specific four radicals to an inorganic support salt. CONSTITUTION:Together with an inorganic support salt such as lithium perchloride, a substance of a large molecular form including at least one radical selected from -SO3M, -COOM, -PO(OM)2, and -PR(O) (OM) in the structure is added at 0.5-10times of amount in the Mole number. In the formula, M is an element of group I of periodic table. The added substance suppresses the movement of anions moving reversely to the movement of cations dissociated mainly in the polymer solid electrolyte, to raise the cation transference number. As a result, the deterioration of capacity of the storage battery following the repeating charge and discharge can be suppressed. In this case, the addition less than 0.5times cannot suppress the movement of the anion source, and the addition more than 10 times cannot maintain the solid condition of the electrolyte.

Description

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

BACKGROUND OF THE INVENTION In recent years, research has been actively conducted on solid polymer electrolytes using polymers such as polyethylene oxide and the like as electrolyte materials.

A battery using this solid electrolyte has advantages such as being leak-free, having a high energy density, and being easily formed into a laminated structure. The most widely tested materials are:
Although this system uses linear polyether, this system has a melting point (60° C.) and has the disadvantage that sufficient ionic conductivity cannot be obtained at temperatures below the melting point.

As an improvement on this, a system using a crosslinked polyether has been proposed. This system has the advantage that it has no melting point and relatively good ionic conductivity can be obtained even near room temperature. This system is Boliete ua! 1 υ It varies depending on the structure of the base portion of the crosslinking agent, and for example, when hexamethylene diiso V anate is used as the crosslinking agent, it is R-40Hzk. ) has the structure. Moreover, the inorganic supporting salt is LiCIO4.

Many substances such as Li0F3SO3 and LiBF6 have been proposed.

However, when a polymer solid electrolyte is applied to a general battery system that uses a lithium intercalated metal compound for the positive electrode and metallic lithium or a lithium alloy for the negative electrode, and is repeatedly charged and discharged, none of the above occurs. Even when the above system was used, there was a problem in that the battery capacity decreased significantly with the charge/discharge cycle.

This is because this type of polymer solid electrolyte is zwitterionic, in which both anion and cation types of ions move.
When the battery is discharged, the anions that migrate become polarized near the negative electrode, but when the battery is next charged, the polarized anions act as a barrier to prevent the movement of cations, leading to a decrease in charging capacity. .

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems.
An object of the present invention is to provide a polymer solid electrolyte that suppresses a decrease in battery capacity due to repeated charging and discharging, and a battery using the same.

In other words, by preferentially causing the movement of cations during charging and discharging, and suppressing the movement of anions as much as possible,
This prevents the capacity from decreasing due to repeated charging and discharging. Therefore, in order to suppress the movement of anions in the polymer solid electrolyte, an anion with a large molecular shape is allowed to coexist with the inorganic supporting salt to form an anion barrier, thereby suppressing the movement of anions.

Structure of the Invention The present invention provides an inorganic support m such as lithium perchlorate.
(0) A substance with a large molecular shape containing at least one group selected from (OM) in its structure is added in an amount of 0.5 to 10 times the number of molecules. A polymer solid electrolyte and a polymer solid electrolyte battery using the same.

Example Hereinafter, the details of the present invention will be explained with reference to Examples.

Trio-type trifunctional bolyate/I/(molecular weight 3000
) 5 parts equivalent of hexamethylene diisocyanate, C
Add 2 parts of an organic material represented by 1 H25 (OH, 20H20) 4803 Li, 2 parts of dimethymu acetamide, and a trace amount of Di-n-butyltin diacetate, apply it on a polyderobylene non-woven cloth, and heat at 80°C with an inert gas. Polyether was crosslinked inside.

Next, add 4 parts of Amof7 vanadium pentoxide, 1 part of acetylene butic, 5 parts of trio-type trifunctional polyether in which 9vt% lithium perchlorate has been dissolved in advance, 1 part of dimethylacetamide, and an equivalent amount of A well-kneaded mixture of hexamethylene diiso ν-anor F and a trace amount of Di-n-butyltin diacetate was applied to the upper surface of the sheet and solidified in an inert gas at 80°C. After drying the sheet, metal lithium was attached and stored in a coin-shaped battery case to prepare a battery.

FIG. 1 shows a comparison of the charging and discharging characteristics of the battery of the present invention and a conventional battery at a temperature of 80°C. A repeated charging/discharging test was conducted between 4v and 2v at a current of 0.1 mm/d. The conventional battery is a polymer solid electrolyte battery that does not use the electrolyte of the present invention.

In this manner, it can be seen that in the battery of the present invention, the discharge capacity after several μth cycles is kept almost constant, capacity reduction is suppressed, and good repeated charge/discharge performance can be obtained.

The -505M or 1000M group listed in the claims here is generally known as an exchange group for ion exchange membranes or ion exchange resins, and 0nH2n+
1 (CiH20H20)*so, M has a structure similar to that commonly used as a surfactant.

The function of the added substance in the present invention is mainly to form anions and cations dissociated in the polymer solid electrolyte (
For example, salt is too much! When lithium oxide is used, the purpose is to suppress the movement of the anion (L1+ cation and alo4- anion). That is, in this example, the basic part of the additive 0nH21+1 (CH20H2
0) The electrostatic force of nSO3- suppresses the movement of anions that try to move in the opposite direction to the movement of cations in the polymer solid electrolyte during charging and discharging of batteries,
This is the same function commonly seen in cation exchange membranes. As a result, the cation transfer number in the polymer solid electrolyte increases, so it is possible to suppress a decrease in capacity due to repeated charging and discharging of the battery. The amount of the present invention added to the polymer solid electrolyte must be sufficient to exhibit the effect of suppressing the movement of anions, and must not exceed the amount that allows the electrolyte itself to maintain its solid state.

If the amount added is less than 0.5 times the amount of the inorganic supporting salt in terms of the number of cells, it is impossible to suppress the movement of the anion stent due to the inorganic supporting salt and to suppress the decrease in capacity due to repeated charging and discharging.

Also, a suitable amount of inorganic supporting salt is about 10 weight percent or less relative to the electrolyte. However, when the amount of inorganic supporting salt is 1, if the amount added exceeds 10 times the number of cells, it becomes difficult for the electrolyte itself to maintain its solid state.

The core part of the substance of the present invention added to the polymer solid electrolyte is not limited to the above, and an organic material that does not contain a 7y kill group or a polyether group can be used. Further, substances using a certain type of inorganic material as the backbone part can also be used as having the same effect.

Effects of the Invention As mentioned above, the present invention can provide a polymer solid electrolyte that suppresses the decrease in battery capacity due to repeated charging and discharging, and a battery 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 battery in repeated charging and discharging.

Claims (2)

[Claims] (1) -SO_3M, -COOM, - with inorganic supporting salt
A substance with a large molecular shape that contains at least one group selected from PO(OM)_2, -PH(O)(OM) (hereinafter M is an element of group I of the periodic table) in its structure. , a polymer solid electrolyte characterized in that an amount of 0.5 to 10 times the amount of an inorganic supporting salt is added in terms of mole number. (2) -SO_3M as an electrolyte together with an inorganic supporting salt;
-COOM, -PO(OM)_2, -PH(O)(OM
) A substance with a large molecular shape containing at least one group selected from
．． A polymer solid electrolyte battery characterized by using a polymer solid electrolyte added in an amount of 5 to 10 times.