KR0173087B1 - Composition of blended solid polymer electro-chemicals - Google Patents

Abstract

The present invention relates to blended solid polymer electrolytes. The blended solid polymer electrolyte of the present invention is about 10 to 60% by weight of polyoligooxyethyloxysebacoyl, about 10 to 60% by weight of polyethylene oxide, about 15 to 25% by weight of lithium salt, preferably about 16 to 64% by weight, About 16 to 64% by weight and about 19 to 20% by weight. The blended solid polymer electrolytes of the present invention are excellent in both mechanical properties and ionic conduction properties, and do not contain any organic solvents, so there is no problem of electrolyte leakage and electrode corrosion, and excellent compatibility, in particular, the manufacturing process is simple and the price is low. Due to the low cost, the processability of the polymer electrolyte film manufactured using the in-line process is greatly improved, and thus it may be usefully used in various electrochemical devices including a lithium polymer secondary battery.

Description

Blend Solid Polymer Electrolyte Compositions

1 is a graph showing the ionic conductivity according to the temperature of the blended solid polymer electrolyte according to the present invention.

The present invention relates to blended solid polymer electrolyte compositions. More specifically, the present invention is excellent in ion conduction properties and mechanical properties, mainly composed of polyethylene oxide, polyoligooxyethyleneoxy sebacoyl and lithium salts, and does not contain any organic solvents, thereby preventing electrolyte leakage and electrode corrosion. The present invention relates to a blended solid polymer electrolyte for lithium polymer secondary batteries having excellent compatibility and a method of manufacturing the same.

With the rapid development of the electric, electronic, telecommunication and computer industries, the demand for high performance and high stability secondary batteries has been gradually increasing. Thinning and miniaturization is also required for batteries. To meet these demands, lithium secondary batteries using liquid electrolytes have been developed. However, these secondary batteries have raised stability problems due to leakage of liquid electrolytes, and methods for mounting positive electrode materials and safety devices have been developed. However, manufacturing cost increases and they are applied to large lithium secondary batteries. There was a problem that can not be done.

In order to solve this problem, recently, a lithium polymer secondary battery (lithium polymer battery, LPB) has been developed has attracted much attention as a new generation of high performance new battery. LPB is largely composed of a negative electrode, an electrolyte and a positive electrode material, lithium, lithium-aluminum alloy, carbon, etc. are used as the negative electrode active material, a solid polymer electrolyte is used as the electrolyte, a transition metal compound, a polymer electrolyte and Composite materials composed of electrically conductive materials are used.

Therefore, LPB can manufacture a thin-film battery at a low cost, control the size and shape as desired, and there is no secondary reaction such as self discharge that can be generated in the liquid electrolyte, and without dilution of the electrolyte solution. It can be manufactured in the form of bipolar and has a very high energy density per unit weight.

Therefore, flexible thin-film LPB can be used as a memory backup battery for smart card, which is a cutting-edge product of the next generation credit society, in addition to portable wireless electronic products, and is easy to develop high voltage and large capacity batteries by stacking. It can also be developed with power.

In response to these expectations, many studies have been made to develop polymer electrolytes exhibiting excellent conductivity. In general, the structural characteristics of the polymer required for use as a polymer electrolyte is that the polar group having an ion coordination ability must be present in the polymer chain and its distribution must be appropriate, and the geometrical shape of the polymer chain necessary for the solvent of the salt is easy, The low glass transition temperature requires good flexibility and low crystallinity which impedes ion conduction.

Surprisingly, there are not many polymers that can satisfy all of the above requirements. However, polyethylene oxide is a polymer material having high crystallinity at room temperature. Polymer electrolytes prepared using these and lithium salts have excellent high-temperature conductivity, but crystallization proceeds as the temperature decreases, resulting in very low ion conductivity near room temperature. Had a problem.

In order to solve this problem, a method of reducing the crystallinity of polyethylene oxide by mixing other polymers with polyethylene oxide has been proposed. For example, European Patent No. 78505 discloses a method for preparing a polymer electrolyte by mixing an elastomer such as butadiene-acrylonitrile copolymer or ethylene-methacrylate copolymer with polyethylene oxide containing lithium perchlorate. It is described. However, in the case of the polymer electrolyte prepared according to this method, since an elastomer having an amorphous structure is mixed with polyethylene oxide, which is a crystalline polymer, the conductivity increase effect can be obtained by reducing the crystallinity of the polymer matrix. There was a problem that phase separation occurs after a certain time.

U.S. Pat.No. 5,102,752 also describes a process for preparing a polymer electrolyte by irradiating a mixture comprising propylene carbonate, dimethoxyethane, polyethylene oxide, lithium trifolate, irradiation crosslinking agent with ultraviolet or electron beam. However, since the polymer electrolyte disclosed in this US patent contains a large amount of organic solvents, the electrode is corroded or the electrolyte leaks, which causes a problem in stability, and also requires a complicated manufacturing process and consumes a lot of time and cost. There were many problems with mass production.

On the other hand, as a solid electrolyte of a lithium polymer secondary battery, a solid polymer electrolyte composed of polyethylene oxide, lithium salt and polyphosphazene [see K.M. Abraham et al., J. Electrochem. Soc., 138: 921 (1991) and solid polymer electrolytes composed of polyethylene oxide, lithium perchlorate and polyvinylpyridine (Jean Li et al., Macromolecules, 26: 4544 (1993)).

However, these solid polymer electrolytes are difficult to synthesize polyphosphazene and polyvinylpyridine, which are polymers mixed to reduce crystallinity in polyethylene oxide, and phase separation due to poor compatibility between two components in mixing with polyethylene oxide. There was a problem that happened.

Accordingly, the present inventors have intensively studied a solid polymer electrolyte that can be used as a solid electrolyte of a lithium polymer secondary battery. As a result, polyethylene oligopolyethylene and polyoligooxyethylene, which is a novel polymer in which methylene units are regularly introduced into a polyethylene oxide main chain, have been studied. By blending osceva coil, it has excellent ion conduction properties and mechanical properties, contains no organic solvents, eliminates electrolyte leakage and electrode corrosion, and makes it easy to manufacture solid polymer electrolytes for lithium polymer secondary batteries. It has been confirmed that the present invention can be completed.

After all, the main object of the present invention is to provide a blended solid polymer electrolyte for lithium polymer secondary batteries that is excellent in ion conduction properties and mechanical properties, does not contain any organic solvents, and has excellent compatibility.

Another object of the present invention is to provide a method for producing the blended solid polymer electrolyte.

It is another object of the present invention to provide a novel polyoligooxyethyleneoxysebacoyl polymer constituting the blended solid polymer electrolyte.

Hereinafter, the blended solid polymer electrolyte of the present invention and a manufacturing method thereof will be described in detail.

Blend solid polymer electrolyte tongue preparation of the present invention,

Polyoligooxyethyleneoxycebacoyl about 10-70 wt%;

About 10-70 wt% polyethylene oxide; And,

Lithium salt is composed of about 15 to 25% by weight.

The polyethylene oxide constituting the blended solid polymer electrolyte of the present invention is a high molecular weight polymer having an average molecular weight of about 5,000,000, and may be known in the art or prepared by a known method. As lithium salts, lithium salts generally used in lithium polymer secondary batteries can be used, but lithium perchlorate is preferably used.

The polyoligooxyethylene ethylene sebacoyl constituting the blended solid polymer electrolyte of the present invention is a novel polymer having a repeating unit represented by the following general formula in which methylene units are regularly introduced into a polyethylene oxide main chain;

Wherein n is a number from 20 to 30.

The polyoligooxyethyleneoxy sebacoyl polymer is prepared by using polyethylene glycol and sebacoyl chloride as monomers, and the synthesis thereof is as follows;

First, 50 g of polyethylene glycol having an average molecular weight of 1000 is dissolved in 150 ml of benzene solvent together with 5 g of triethylamine and injected into the reactor. Subsequently, 12.2 g of sebacoyl chloride was dissolved in 50 ml of benzene and placed in a dropping funnel, and slowly added dropwise to the reactor over 1 hour. The reactor temperature is maintained at 5 ° C. during the injection of the reactants and the reactants are vigorously stirred with a stirrer while flowing high purity nitrogen. After the injection of the reactants, the reaction was carried out for 6 hours by raising the reactor temperature to 60 ℃. After the reaction, the product was filtered to remove by-product triethylamine and hydrogen chloride, and the filtered solution was transferred to the lyophilizer again to completely remove the benzene solvent under vacuum for 48 hours to obtain a polyoligooxyethyleneoxy having an average molecular weight of 26,300 as a white powder. Prepare seba conyl.

Preferred blended solid polymer electrolyte compositions of the present invention comprise about 16-64% by weight of polyoligooxyethyleneoxycebacoyl; About 16-64 weight percent polyethylene oxide; And it consists of 19-20 weight% of lithium salts.

In addition, according to the present invention, polyethylene oxide, polyoligooxyethyleneoxy sebacoyl and lithium salts are dissolved in an organic solvent at a ratio of about 10 to 70% by weight, about 10 to 70% by weight and about 15 to 25% by weight, respectively. Preparing a highly viscous homogeneous solution; Casting the high viscosity homogeneous solution to obtain a film; And, drying the film to completely remove moisture and solvent.

Detailed description of the method for producing a blended solid polymer electrolyte according to the present invention, the polyoligooxyethyleneoxy sebacoyl having a repeating unit of the general formula and a lithium salt, preferably lithium perchlorate, respectively Organic solvent, preferably in a ratio of 10-70%, about 10-70% and about 15-25%, preferably about 16-64%, about 16-64% and about 19-20% Preferably dissolved in acetonitrile and stirred at about 60 ° C. for about 24 hours to produce a uniform high viscosity solution. The resulting highly viscous homogeneous solution is then cast in a Teflon vessel according to conventional methods known in the art to prepare a film, the solvent is removed in the hood, and finally dried in a vacuum oven at about 80 ° C. for about 48 hours. Water and solvent are completely removed to obtain a polymer electrolyte film in thin film form.

The blended solid polymer electrolyte film of the present invention prepared as described above not only has excellent mechanical properties to be free-standing (free-standing) as shown in Table 1 of Example 5 below, the solid polymer electrolyte film 12mm in diameter When the specimens were made in the form of disks and measured using a frequency response analyzer to measure ionic conductivity over various temperature ranges, as shown in Figure 1, the ionic conductivity of 3 to 4.5 x 10 ^-5 Ω ^-1 cm ^-1 was excellent. It has ion conducting properties.

As shown in Table 1 and FIG. 1, the solid polymer electrolytes of the present invention have excellent mechanical properties and ionic conductivity, and do not contain any organic solvents, so there is no problem of electrolyte leakage and electrode corrosion, and excellent compatibility. In particular, the manufacturing process is simple and inexpensive, so that the processability of the polymer electrolyte film using the in-line process is greatly improved, and thus it may be usefully used in various electrochemical devices including lithium polymer secondary batteries.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not limited to these examples.

Example 1

16.1% by weight of polyoligooxyethyleneoxysebacoil, 64.5% by weight of polyethylene oxide and 19.4% by weight of lithium perchlorate were added to the acetonitrile solvent and stirred at 60 ° C. for 24 hours using a stirrer to completely dissolve all contents. A high viscosity solution was obtained. This was cast in a Teflon container to obtain a film, the solvent was evaporated in a hood, and finally dried in a vacuum oven at 80 ° C. for 48 hours to prepare a polymer electrolyte film in a thin film form in which water and solvent were completely removed.

Example 2

In preparing the polymer electrolyte in Example 1, the polymer was polymerized in the same manner as in Example 1, except that 32.2% by weight of polyoligooxyethyleneoxysebacoyl, 48.4% by weight of polyethylene oxide, and 19.4% by weight of lithium picchlorate were mixed. An electrolyte film was prepared.

Example 3

The polymer electrolyte film was manufactured in the same manner as in Example 1, except that 48.4 wt% of polyoligooxyethyleneoxy sebacoyl, 32.2 wt% of polyethylene oxide, and 19.4 wt% of lithium perchlorate were mixed when preparing the polymer electrolyte in Example 1. Was prepared.

Example 4

The polymer electrolyte film was manufactured in the same manner as in Example 1, except that 64.5 wt% of polyoligooxyethyleneoxy sebacoyl, 16.1 wt% of polyethylene oxide, and 19.4 wt% of lithium perchlorate were mixed when preparing the polymer electrolyte in Example 1. Was prepared.

Example 5

The mechanical properties of the polymer electrolyte films prepared in Examples 1 to 4 were measured, and disk-shaped specimens were made by using a punch having a diameter of 12 mm, and ions different in temperature over various temperature ranges using a frequency response analyzer. Conductivity was measured. The results were as shown in Table 1 and FIG.

As shown in Table 1 and FIG. 1, the blended solid polymer electrolyte film of the present invention not only has excellent mechanical properties such as free-standing, but also 3 to 4.5 x 10. Ω cm The ion conductivity was also shown to be excellent.

As described and demonstrated in detail above, the blended solid polymer electrolytes of the present invention are excellent in both mechanical properties and ionic conduction properties, and do not contain any organic solvents, so there is no problem of electrolyte leakage and electrode corrosion, and compatibility. Excellent, in particular, the manufacturing process is simple and inexpensive, the processability is greatly improved when manufacturing the polymer electrolyte film using the in-line process can be useful in various electrochemical devices including lithium polymer secondary batteries.

Claims (3)

10-70 weight% of polyethylene oxides: 10-70 weight% of poly oligooxyethyleneoxy sebacoyl which has a repeating unit represented with the following general formula; [Wherein n is a number from 20 to 30]; And 15-25 wt% of a lithium salt. 10 to 70 wt% polyethylene oxide; 10 to 70% by weight of poly oligooxyethyleneoxy sebacoyl having a repeating unit represented by the following general formula; [Wherein n is a number from 20 to 30]; And, 15 to 225% by weight of the lithium salt dissolved in an organic solvent to prepare a high viscosity uniform solution; Casting the high viscosity homogeneous solution to obtain a film; And drying the film to completely remove the water and the solvent. Polyoligooxyethyleneoxy sebacoyl having a repeating unit represented by the following general formula; Wherein n is a number from 20 to 30.