KR101389732B1 - Polymer electrolyte for lithium secondary battery - Google Patents

Abstract

It relates to a polymer electrolyte for a lithium secondary battery, and a lithium secondary battery comprising the polymer electrolyte.

Description

Polymer electrolyte for lithium secondary battery {POLYMER ELECTROLYTE FOR LITHIUM SECONDARY BATTERY}

The present application relates to a polymer electrolyte for a lithium secondary battery, and a lithium secondary battery including the polymer electrolyte.

In order to cope with the rapidly increasing energy consumption and to change to an environment-friendly form of consumption, a lot of research is being focused on alternative energy and alternative power sources, namely electrochemical energy production methods. The storage and conversion of electrochemical energy includes secondary batteries, fuel cells, and capacitors, and many studies on lithium secondary batteries, which are known to have the best discharge performance, are being conducted.

Rechargeable batteries are the three key strategic products that will lead the domestic electronic information equipment industry along with semiconductors and displays. They determine the performance of future mobile IT products closely related to the 21st century human life such as mobile phones, laptops, computers, camcorders, MP3s, and PDAs. Of course, the importance of electric vehicles is increasing.

Among them, lithium polymer batteries are the most studied due to high energy density and discharge voltage, and are currently commercialized in mobile phones and camcorders.

Currently, as an electrolyte used in lithium polymer batteries, a polyethylene oxide [poly (ethylene oxide), PEO] -based polymer electrolyte is known as one of the highest commercially available polymer electrolytes. However, the polymer electrolyte using PEO has a relatively high ionic conductivity of 10 ⁻⁴ S / cm at a high temperature of 60 ° C. or higher, but has a problem of decreasing the ionic conductivity to 10 ⁻⁸ S / cm at room temperature. This problem is due to the high crystallinity (χ = ˜80%) of PEO. The movement of ions in the electrolyte is caused by the segmental motion of the polymer, which is limited in the crystal region. Therefore, research has been conducted to develop a polymer electrolyte having high ionic conductivity and mechanical strength even at a relatively low temperature and room temperature by suppressing crystallinity of the polymer electrolyte.

Conventional solid polymer electrolytes for lithium secondary batteries have introduced various additives for the purpose of controlling the crystallinity of the polymer matrix PEO to secure ion conductivity at room temperature. For example, Korean Patent No. 10-0722834 discloses a "method of manufacturing a polymer electrolyte composite material and a lithium polymer battery having a solid polymer electrolyte composite material prepared therefrom". However, in most cases, the crystallinity is controlled when the additive is introduced, but at the same time, there is a problem that the mechanical properties are weakened. In addition, the size of these additives themselves affects the chain mobility of the PEO chain, which leads to an increase in the glass transition temperature (T _g ), which is a very important factor in ion conduction at room temperature and low temperature. Holding it.

The present application provides a polymer electrolyte for a lithium secondary battery including a polymer matrix, a lithium salt, and a polyhedral silsesquioxane having a cage structure, and a lithium secondary battery including the polymer electrolyte, a cathode, and an anode. I would like to.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

A first aspect of the present application can provide a polymer electrolyte for a lithium secondary battery, including a polymer matrix, a lithium salt, and a polyhedral silsesquioxane having a cage structure.

According to a second aspect of the present disclosure, a lithium secondary battery including a polymer electrolyte for a lithium secondary battery, a cathode, and an anode according to the first aspect of the present disclosure may be provided.

According to the present invention, a polyhedral silsesquioxane having a cage structure as a nanocomposite additive in a polymer electrolyte of a lithium secondary battery has improved ionic conductivity through crystallinity control and high mechanical strength through supplementation of properties of the electrolyte. Solid polymer electrolytes can be obtained. In addition, it is possible to provide a solid polymer electrolyte with improved performance, which can solve the stability problems of the liquid electrolyte and the gel polymer electrolyte used in the conventional lithium ion battery.

In addition, since the polymer electrolyte of the present application has a strong mechanical strength, the performance can be maintained even if the thickness is reduced, and as a result, it is possible to realize thinning and low cost of a lithium secondary battery.

In addition, since the polymer electrolyte of the present application has high ionic conductivity and mechanical properties at room temperature at the same time, it may contribute to the commercialization of a high capacity lithium polymer secondary battery having a future stability.

1 is a graph showing the results of differential scanning calorimeter (DSC) analysis of a polymer electrolyte according to an embodiment of the present application.
Figure 2 is a graph showing the ionic conductivity at room temperature of the polymer electrolyte according to an embodiment of the present application.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when an element is referred to as "including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

The terms "about "," substantially ", etc. used to the extent that they are used herein are intended to be taken as a reference to either the numerical value or to the numerical value when the manufacturing and material tolerance inherent in the stated meaning is presented, Accurate or absolute numbers are used to prevent unauthorized exploitation by unauthorized intruders of the mentioned disclosure. Also, throughout the present specification, the phrase " step "or" step "does not mean" step for.

Throughout this specification, when a member is " on " another member, it includes not only when the member is in contact with the other member, but also when there is another member between the two members.

Throughout the present specification, the term " combination thereof " included in the expression of the machine form means one or more combinations or combinations selected from the group consisting of the constituents described in the expression of the machine form, Quot; and " the "

A first aspect of the present application can provide a polymer electrolyte for a lithium secondary battery, including a polymer matrix, a lithium salt, and a polyhedral silsesquioxane having a cage structure. For example, the polymer matrix may include, but is not limited to, a polar element such as oxygen, nitrogen, or sulfur in the polymer. For example, the polymer matrix, polyethylene (poly (ethylene oxide)); PEO, poly (propylene oxide); PPO], polyacrylonitrile (poly (acrylonitrile)); PAN], poly (vinyl chloride); PVC], polyvinylidene fluoride (poly); PVDF], poly (methyl methacrylate); Various forms prepared using grafting, crosslinking, or blending based on a polymer matrix containing one selected from the group consisting of PMMA, polysiloxane, polyphosphazene, and combinations thereof And / or a copolymer of the kind, but is not limited thereto.

According to one embodiment of the present application, the polymer matrix is polyethylene oxide [poly (ethylene oxide); PEO, poly (propylene oxide); PPO], polyacrylonitrile (poly (acrylonitrile)); PAN], poly (vinyl chloride); PVC], polyvinylidene fluoride (poly); PVDF], poly (methyl methacrylate); PMMA], polysiloxane (polysiloxane), polyphosphazene (polyphosphazene), and may contain one selected from the group consisting of, but is not limited thereto.

For example, the polyhedral silsesquioxane of the cage structure may include, but is not limited to, a polyhedral oligomeric silsesquioxane of the cage structure.

Ionic conduction of the solid polymer electrolyte for a lithium secondary battery occurs in an amorphous region of the polymer included in the polymer matrix. Therefore, in order to increase the ionic conductivity of the solid polymer electrolyte, it is necessary to lower the crystallinity by inhibiting the interaction between the chains of the crystalline polymer, and for this, an additive may be introduced. However, in the existing additive system, as the additive is introduced, the crystallinity of the polymer is controlled to increase the ionic conductivity, but at the same time, there is a problem that causes a large decrease in the mechanical properties. In order to alleviate these drawbacks, a polyhedral silsesquioxane with a cage structure that complements the properties of the electrolyte through the central silsesquioxane cage structure is added as an additive. The complementary solid polymer electrolyte may be implemented, but is not limited thereto.

According to one embodiment of the present application, the polyhedral silsesquioxane of the cage structure may include PEG-polyhedral silsesquioxane (polyethylene glycol-polyhedral silsesquioxane) containing polyethylene glycol (PEG) as a functional group. However, it is not limited thereto.

According to the exemplary embodiment of the present application, the polyethylene glycol may include about 1 to about 11 ethylene oxide repeating units, but is not limited thereto.

For example, the polyethylene glycol is about 1 to about 11, about 3 to about 11, about 5 to about 11, about 7 to about 11, about 9 to about 11, about 1 But may include from about 11 to about 11, about 1 to about 9, about 1 to about 7, about 1 to about 5, or about 1 to about 3 ethylene oxide repeat units, It is not limited.

Ethylene oxide (EO) contained in the polyethylene glycol forms a complex through a coordinating bond in a lithium salt and an electrolyte to perform a role of ionic conduction. Accordingly, the repeating unit of the ethylene oxide is increased. It means to supply a large number of ion conducting sites, and at the same time it is possible to move more lithium free ions due to the increased dissociation of the lithium salt. In addition, the presence of ethylene oxide repeating units of polyethylene glycol having a low glass transition temperature decreases the glass transition temperature of the polymer electrolyte, resulting in the active polymer movement. For example, the polyethylene glycol may cause an increase in the ionic conductivity of the polymer electrolyte for lithium secondary battery due to the above effects, but is not limited thereto.

According to one embodiment of the present application, the polyethylene glycol is connected to the silicon atoms contained in the polyhedral silsesquioxane, and may be connected to each of 1 to 8 silicon atoms, but is not limited thereto. . For example, the polyethylene glycol is one silicon atom, two silicon atoms, three silicon atoms, four silicon atoms, five silicon atoms, six silicon atoms of the polyhedral silsesquioxane containing eight silicon atoms. It may include, but is not limited to, those linked to each of atoms, seven silicon atoms, or eight silicon atoms.

For example, the additive PEG-polyhedral silsesquioxane that can be introduced into a solid polymer electrolyte composed of a polymer matrix and a lithium salt may include a polyethylene glycol (PEG) functional group located in 1 to 8 directions, but It is not limited. Polyethyleneglycol exhibits a high conductivity of 1 x 10 ^-3 S / cm when introduced as a plasticizer into the gel type polymer electrolyte together with polyethylene oxide and lithium salt. Therefore, PEG-polyhedral silsesquioxane is added to the polymer matrix to reduce the crystallinity of the polymer matrix and at the same time, polyethyleneglycol, which is a functional group that runs in up to 8 directions, can dissociate salts like polyethylene oxide, which is the polymer matrix, on the electrolyte. This ability to compensate for the lack of dissociation of lithium salts in the polymer matrix. Increased salt dissociation means that the density of dissociated lithium free ions in the electrolyte is increased, resulting in improved ionic conductivity of the solid polymer electrolyte.

According to the exemplary embodiment of the present application, the PEG-polyhedral silsesquioxane may include, but is not limited to, one represented by the following Chemical Formula 1.

[Chemical Formula 1]

R in Formula 1 is CH ₂ CH ₂ (OCH ₂ CH ₂ ) _m OCH ₃ , m = 1 to 11.

In the case of PEG-polyhedral silsesquioxane of Chemical Formula 1, a functional group is connected to eight silicon atoms located in eight directions based on a central cage structure. The eight functional groups each include polyethylene glycol, which is widely used as a plasticizer in the electrolyte system, to compensate for the insufficient salt dissociation ability of the polymer matrix and to control the crystallinity of the polymer matrix as an additive, but is not limited thereto. For example, the PEG-polyhedral silsesquioxane is a nano-sized additive that lowers the glass transition temperature as the introduction amount increases, thereby activating the movement of molecules, and at the same time, the crystal structure is controlled by the stable cage structure. It can compensate for the mechanical strength that may fall due to, but is not limited thereto.

According to one embodiment of the present application, the content of the polyhedral silsesquioxane may be about 5 wt% to about 50 wt% based on the total weight of the polymer electrolyte, but is not limited thereto. For example, the polyhedral silsesquioxane is about 5 wt% to about 50 wt%, about 10 wt% to about 50 wt%, about 20 wt% to about 50 wt%, based on the total weight of the polymer electrolyte. , About 30 wt% to about 50 wt%, about 40 wt% to about 50 wt%, about 5 wt% to about 40 wt%, about 5 wt% to about 30 wt%, about 5 wt% to about 20 wt% Or about 5 wt% to about 10 wt%, but is not limited thereto.

For example, as the amount of PEG-polyhedral silsesquioxane introduced as an additive increases, the glass transition temperature (T _g ) of the polymer contained in the polymer matrix is lower than that of T _g of an electrolyte composed of only the polymer and lithium salt. May be, but is not limited thereto. Existing additives introduced into the conventional solid polymer electrolyte system have an effect of controlling crystallinity due to their size, but have a problem that the glass transition temperature is increased by decreasing the mobility of the polymer chain. However, the additive PEG-polyhedral silsesquioxane is a nano-sized additive, which lowers the glass transition temperature to activate molecular movement at low temperature and room temperature. As a result, the ion at room temperature is higher than the electrolyte composed of polymer matrix and lithium salt only. It can bring about improved conductivity.

According to one embodiment of the present application, the polymer matrix may include polyethylene oxide [poly (ethylene oxide), PEO], but is not limited thereto.

According to one embodiment of the present application, the molar ratio of ethylene oxide included in the polyethylene oxide and lithium included in the lithium salt may be about 4: 1 to about 60: 1, but is not limited thereto. For example, the molar ratio of ethylene oxide included in the polyethylene oxide and lithium included in the lithium salt is about 4: 1 to about 60: 1, about 4: 1 to about 50: 1, about 4: 1 to about 40 : 1, about 4: 1 to about 30: 1, about 4: 1 to about 24: 1, about 4: 1 to about 20: 1, about 4: 1 to about 16: 1, about 4: 1 to about 12 : 1, about 4: 1 to about 8: 1, about 4: 1 to about 24: 1, about 4: 1 to about 20: 1, about 4: 1 to about 16: 1, about 4: 1 to about 12 : 1, about 4: 1 to about 8: 1, about 8: 1 to about 60: 1, about 12: 1 to about 60: 1, about 16: 1 to about 60: 1, about 20: 1 to about 60 : 1, about 30: 1 to about 60: 1, about 40: 1 to about 60: 1, about 50: 1 to about 60: 1, or about 10: 1 to about 14: 1, but not limited thereto. It doesn't happen.

According to one embodiment of the present invention, the lithium salt is lithium hexafluorophosphate (LiPF ₆ , lithium hexafluorophosphate), lithium tetrafluoroborate (LiBF ₄ , lithium tetrafluoroborate), lithium perchlorate (LiClO ₄ , lithium perchlorate), lithium chloride (LiCl, lithium chloride), lithium triflate, lithium bis (oxalato) borate [LiBOB, lithium bis (oxalato) borate], lithium bis (nonnafluorobutylsulfonyl) methane ], Lithium difluoro bisoxalato phosphate, lithium difluoro (oxalate) borate (LiDFOB, lithium difluoro (oxalate) borate), lithium bis (pentafluoroethylsulfonyl) amide [LiBETI , lithium bis (pentafluoroethylsulfonyl) amide], lithium bis (trifluoromethanesulfonyl) imide [LiTFSI, lithium bis (trifluoromethanesulfonyl) imide] and combinations thereof It may include one selected from the group, but is not limited thereto.

The second aspect of the present disclosure may provide a lithium secondary battery, including a polymer electrolyte for a lithium secondary battery, a cathode, and an anode according to the first aspect of the present disclosure.

For example, the lithium secondary battery including the polymer electrolyte for lithium secondary battery, the cathode, and the anode according to the first aspect of the present application may include a high capacity lithium polymer secondary battery having enhanced stability. It may be a thin film, low-cost lithium polymer secondary battery, but is not limited thereto.

In one embodiment of the present application, the cathode is LiMn ₂ O ₄ , LiNi ₂ O ₄ , LiTi ₂ O ₄ , LiTiS ₂ , LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , Li ₂ MnO ₃ , LiFePO _4, LiFePO ₄ , LiFePO ₄ F, LiMnPO ₄ , LiCoPO ₄ , LiNiPO ₄ , and may include a compound selected from the group consisting of, but is not limited thereto.

In one embodiment of the present application, the anode is graphite (graphene), graphene (graphene), low temperature calcined carbon, calcined coke, vanadium oxide, lithium vanadium oxide, lithium germanium oxide, lithium titanate oxide, silicon, silica , Lithium silicide, and combinations thereof may be included, but is not limited thereto. For example, the lithium titanate oxide may be Li ₄ Ti ₅ O ₁₂ , but is not limited thereto. For example, lithium silicide may be Li ₁₂ Si ₇ , but is not limited thereto.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[ Example ]

PEG Polyhedron Silsesquioxane  Preparation of Added Polymer Electrolyte

In this embodiment, a solid polymer electrolyte to which PEG-polyhedral silsesquioxane (polyethylene glycol-polyhedral silsesquioxane) was added was prepared. Reagents for the preparation were purchased from Aldrich and Hybrid Plastic. Anhydrous acetonitrile (99.8%, Aldrich) was used as a solvent, polyethylene oxide (PEO, Aldrich) having a molecular weight of 1,000,000 and lithium hexafluorophosphate (lithium hexafluorophosphate, LiPF ₆ , (Aldrich)) were used. In addition, a solid polymer electrolyte in the form of a thin film was prepared using PEG-polyhedral silsesquioxane (Hybrid Plastics) as an additive.

PEG-polyhedral silsesquioxane was added as an additive to the polymer matrix PEO at 5 wt%, 10 wt%, 20 wt%, and 50 wt% of the total weight. Then, to form a PEO-lithium salt complex, the amount of LiPF ₆ , which is a lithium salt, was added at a ratio of [EO] / [Li] of 12/1 and these were dissociated in an organic solvent, acetonitrile. For complete dissociation of lithium salts and stable complex formation with PEO and even dispersion of PEG-polyhedral silsesquioxanes, the solution is stirred uniformly (up to 24 hours) using a magnetic bar in an oil-bath at 50 ° C. A solution was made. At this time, sonication was performed in the middle so that the PEG-polyhedral silsesquioxane additive was uniformly well dispersed throughout. The homogeneous solution obtained by this process was put in Teflon petridish to form an electrolyte membrane using a solution casting method. After that, the electrolyte membrane was dried for 3 to 4 days in a glove box under high purity nitrogen to completely block contact with moisture at room temperature, and the polymer with PEG-polyhedral silsesquioxane was added by sufficiently removing the solvent acetonitrile. An electrolyte was obtained.

Measurement of glass transition temperature and crystallinity of polymer electrolyte

In this embodiment, the solid polymer electrolyte containing only 0, 5, 10, 20, 50 wt% of PEG-polyhedral silsesquioxane to the total weight of PEO and lithium salt (LiPF ₆ ) and the solid polymer electrolyte containing pure PEO Glass transition temperature and crystallinity were measured. 1 is a graph showing the results of analyzing the solid polymer electrolytes with differential scanning calorimeters (DSC), and Table 1 shows the numerical results of FIG. 1. According to the results shown in FIG. 1 and Table 1, as the amount of PEG-polyhedral silsesquioxane introduced as an additive was increased, the crystallinity of PEO was decreased, so that the peak area at the melting temperature and the melting section decreased. .

[Table 1]

PEG Polyhedron Silsesquioxane  Measurement of Ionic Conductivity of Polymer Electrolyte According to Contents

In this example, the ionic conductivity at room temperature of the solid polymer electrolyte to which PEG-polyhedral silsesquioxane was added to PEO and lithium salt (LiPF ₆ ) was measured. Table 2 quantifies the ionic conductivity at room temperature of the solid polymer electrolyte to which lithium salt (LiPF ₆ ) is added 0, 5, 10, 20, 50 wt% of PEG-polyhedral silsesquioxane to the total weight. It is shown. Ionic conductivity at room temperature of the solid polymer electrolyte was measured by an AC impedance method using an AC impedance analyzer (Solatron Frequency Response Analyzer 1252A coupled with SI 1287 Electrochemical Interface). Stainless steel (stainless steel) electrode was used to measure the ion conductivity, and the sample was taken in a circular shape having a diameter of 1 cm and inserted between the electrodes in the cell and measured in a wide frequency range. After obtaining the bulk resistance of the electrolyte from the measured AC-Cole plot, the ionic conductivity was calculated using the following equation:

R = ρL / A, ρ = RA / L, and σ = 1 / ρ

In the above formula, ρ, R, A, L, and sigma mean specific resistivity, measured resistance, cross-sectional area of sample, distance between electrodes, and ion conductivity, respectively.

[Table 2]

According to Table 2, in the case of the polymer electrolyte containing no PEG-polyhedral silsesquioxane, the polymer electrolyte containing PEG-polyhedral silsesquioxane was 3.5 x 10 ^-7 S / cm. As the amount of PEG-polyhedral silsesquioxane introduced increases, the ionic conductivity increases, and when 50 wt% of PEG-polyhedral silsesquioxane is added, the ionic conductivity increases to 4.0 x 10 ^-6 S / cm. Was observed.

Lithium salt  Measurement of Ionic Conductivity of Polymer Electrolyte According to Kinds

In this example, the ionic conductivity at room temperature of the solid polymer electrolyte containing LiTFSI or LiClO ₄ , which is a lithium salt instead of PEO and LiPF ₆ , was measured. 2 is a graph showing ionic conductivity at room temperature of a polymer electrolyte including LiTFSI, LiPF ₆ , and LiClO _4, respectively. As shown in Figure 2, when using LiTFSI instead of LiPF ₆ , the ionic conductivity at room temperature was up to 4.3 x 10 ^-5 S / cm.

Mechanical strength measurement of polymer electrolyte

In this embodiment, the universal testing machine (Universal) to confirm the mechanical strength of the solid polymer electrolyte in which 0, 5, 10, 20, 50 wt% of PEG-polyhedral silsesquioxane is added to the total weight of PEO and lithium salt (LiPF ₆ ). Tensile tests were conducted using a testing machine (UTM). For the test, specimens were manufactured according to the standards of the American Society for Testing and Materials (ASTM), and tensile strain and tensile strength were applied by applying deformation or fracture caused by the force by applying a force to the specimen. stress) was measured. Yield stress, the yield stress (yield stress) and yield strain (yield strain), the strain at the yield point at which the elastic deformation is obtained is numerically shown in Table 3 according to the type of the solid polymer electrolyte. As shown in Table 3, in the case of the polymer electrolyte in which PEG-polyhedral silsesquioxane is introduced, yield stress is higher than that of the polymer electrolyte in which PEG-polyhedral silsesquioxane is not introduced as a result of supplementing properties of the cage structure. At least 1.6 times to maximum 2.8 times increased, while yield stain (yield stain) was also shown to increase significantly by 2 to 3 times.

[Table 3]

It will be understood by those of ordinary skill in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention .

Claims (12)

A polymer electrolyte for a lithium secondary battery comprising a polymer matrix, a lithium salt, and a polyhedral silsesquioxane having a cage structure,
The polyhedral silsesquioxane of the cage structure is represented by the following formula (1) and includes a PEG-polyhedral silsesquioxane (polyethylene glycol-polyhedral silsesquioxane) containing a polyethylene glycol (PEG) as a functional group,
The PEG-polyhedral silsesquioxane content is more than 0 wt% to 20 wt% based on the total weight of the polymer electrolyte.
Polymer electrolyte for lithium secondary battery:
[Chemical Formula 1]

R in Formula 1 is CH ₂ CH ₂ (OCH ₂ CH ₂ ) _m OCH ₃ , m = 1 to 11.
delete The method of claim 1,
The polyethylene glycol is one to 11 ethylene oxide (ethylene oxide) comprising a repeating unit, a polymer electrolyte for a lithium secondary battery.
The method of claim 1,
The polyethylene glycol is connected to each of 1 to 8 silicon atoms contained in the polyhedral silsesquioxane, polymer electrolyte for lithium secondary battery.
delete The method of claim 1,
The polyhedral silsesquioxane content is 5 wt% to 20 wt% or less, based on the total weight of the polymer electrolyte.
The method of claim 1,
The polymer matrix is polyethylene (poly (ethylene oxide)); PEO, poly (propylene oxide); PPO], polyacrylonitrile (poly (acrylonitrile)); PAN], poly (vinyl chloride); PVC], polyvinylidene fluoride (poly); PVDF], poly (methyl methacrylate); PMMA], polysiloxane [polysiloxane], polyphosphazene [polyphosphazene], and containing a selected from the group consisting of a combination, a polymer electrolyte for a lithium secondary battery.
The method of claim 7, wherein
Mole ratio of ethylene oxide contained in the polyethylene oxide and lithium contained in the lithium salt is 4: 1 to 60: 1, the polymer electrolyte for a lithium secondary battery.
The method of claim 1,
The lithium salt is lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium perchlorate (LiClO ₄ ), lithium chloride (LiCl), lithium triflate (LiTf), lithium hexafluoroalsenate (LiAsF ₆ ), lithium sulfide (Li ₂ S), lithium sulfate (Li ₂ SO ₄ ), lithium phosphate (Li ₃ PO ₄ ), lithium citrate (Li ₃ C ₆ H ₅ O ₇ ), lithium bis (oxalato ) Borate (LiBOB), lithium bis (nonnafluorosulfonyl) methane, lithium difluoro bisoxalato phosphate (LiF ₄ OP), lithium difluoro (oxalate) borate (LiDFOB), lithium bis (pentafluoro Ethylsulfonyl) amide (LiBETI), lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), lithium tris (trifluoromethanesulfonyl) methide [LiC (SO ₂ CF ₃ ) ₃ ] and their Polymer electrolyte for lithium secondary batteries, including those selected from the group consisting of combinations .
A lithium secondary battery comprising the polymer electrolyte for a rechargeable lithium battery according to any one of claims 1, 3, 4, and 9, a cathode, and an anode.
11. The method of claim 10,
The cathode is LiMn ₂ O ₄ , LiNi ₂ O ₄ , LiTi ₂ O ₄ , LiTiS ₂ , LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , Li ₂ MnO ₃ , LiFePO _4, LiFePO ₄ , A lithium secondary battery comprising a compound selected from the group consisting of LiFePO ₄ F, LiMnPO ₄ , LiCoPO ₄ , LiNiPO ₄ , and combinations thereof.
11. The method of claim 10,
The anode is graphite, graphene, low temperature calcined carbon, calcined coke, vanadium oxide, lithium vanadium oxide, lithium germanium oxide, lithium titanate oxide, silicon, silica, lithium silicide, and combinations thereof What is selected from the group consisting of, the lithium secondary battery.

Images