KR100659583B1 - Sulfur-sulfur links containing novel conducting polymer based cathode materials, and lithium rechargeable battery obtained therefrom - Google Patents

Abstract

Provided are a positive electrode composition of a conductive polymer material containing a S-S bond, and a lithium secondary battery using the composition which is increased in the capacity maintenance characteristics according to the number of charge/discharge and is remarkably improved in electrical conductivity and electrochemical properties. The positive electrode composition comprises a copolymer of a polydithiodianiline repeating unit represented by the formula 1 and an N-aryl amine derivative, wherein X is H, Li, Na or K; Z is F, Cl, Br, I, ClO4, PF6, BF4, CF3SO3, HSO4 or C12H25C6H4SO3; k, k1' and k2' represent a molar ratio and are 0.01-0.5, respectively; m represents a molar ratio and is 0.05-0.95; and n represents a repeating unit and is 2-10,000. The monomer of an N-aryl amine derivative is introduced into the dithiodianiline derivative by chemical polymerization or electropolymerization.

Description

Sulfur-sulfur links containing novel conducting polymer based cathode materials, and lithium rechargeable battery obtained therefrom}

Figure 1 shows the Cyclic Voltammogram (CV) during the electropolymerization reaction, (a) is 2-2'- dithio dianiline (DTDA) containing 50mM, (b) is 2-2'- dicy This is the case of a solution in which ODA aniline (DTDA) and diphenylamine (DPA) are mixed in a 1: 1 ratio (insertion rate: initial one cycle).

2 is a GPC graph of the composite cathode composition of the present invention analyzed using DMF as the moving solvent and the reference material as PS.

3 is an FT-IR spectrum for DTDA, PDTDA and the composite positive electrode composition of the present invention.

4 is Raman spectra for DTDA, PDTDA and the composite positive electrode composition of the present invention.

5 is a morphology of PDTDA and the composite anode of the present invention.

The present invention relates to a positive electrode composition for a lithium secondary battery and a lithium secondary battery using the same, wherein the N-aryl amine derivative is added to a new organic disulfur-based polymer positive electrode composition, particularly a positive electrode composition made of a conventional dithiodioline (DTDA) derivative. It relates to a composite positive electrode composition obtained by copolymerization or mixing after polymerization or chemically, respectively, and a lithium secondary battery using the same.

Lithium secondary batteries have recently been spotlighted as the most advanced batteries due to their high energy density, high output density, environmental friendliness, and safety. There are also many possibilities for electric and hybrid cars.

Among these, lithium ion batteries currently widely commercialized include cathodes used as transition metal active materials capable of intercalation and deintercalation of lithium ions, and intercalation and deintercalation of lithium ions. A battery which is formed by filling an anode using this carbon-based material and an organic electrolyte in which lithium ions are transported in the middle thereof, wherein lithium ions cause an oxidation-reduction reaction at the cathode and the anode to cause intercalation / deintercalation. Electrical energy is obtained.

As a cathode of a lithium secondary battery, an oxide of lithium and a transition metal capable of intercalation and deintercalation of lithium ions and a potential of 3 to 4.5 V higher than the electrode potential of Li / Li + are mainly used. (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ) lithium manganese oxide (LiMnO ₂ ), and the like. However, with the development of electronic devices, there is a demand for batteries with improved battery performance such as energy density and battery capacity.

To this end, a method of introducing elemental substituents into existing lithium-based metal oxides (see JR Dahn et al., Electrochemical and Solid-State Letters, 4, A191, 2000, JY Lee et al., J. Power Sources, 81) -82, 416, 1999), various kinds of LiFeO ₂ such as iron-based groutite, zigzag layered, layered, etc. can be synthesized for reversible 4V discharge, or Fe ³⁺ / ²⁺ NASICON type Fe ₂ (SO ₄ ) ₃ or Olivin type LiFePO ₄ using redox have been studied. (J. Yamaki et al., J. Power Sources, 68, 711, 1997, JB Goodenough et al., J. Electrochem. Soc., 144, 1609, 1997)

Anode compositions using organic materials other than inorganic materials have been continuously studied using conductive polymers such as polyaniline, polyacetylene, polypyrrole and polythiophene since the early 1980s. However, the capacity improvement was difficult compared to the conventional inorganic oxide.

Recently, a cathode active material for a lithium secondary battery has been developed using organic sulfur, since a high electric capacity is possible by reversibly performing efficient cutting / recombination (SS ↔ 2SH) using a disulfide bond (SS). to be. The composition has a much higher theoretical capacity than lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), and the like, which are common electrode materials.

Organic disulfide electrode materials also have the advantages of low cost, low toxicity and high energy density. Here, the formation of S-S bonds occurs when the organic disulfide is electrochemically oxidized to a disulfide polymer, and the cleavage of S-S bonds occurs when the polymer is electrochemically reduced to monomers.

This process is caused by the process of the lithium cation coming out of the polymer matrix (oxidation) and entering it (reduction). If many sulfur reactor molecules are composed (-(S) _n- ), polysulfide has a much higher energy density than that of disulfide, which can be 1500 to 3500 mWh / g or more with increasing number of sulfur molecules. Will be.

Of these, 2,5-dimercapdo- [3,4-thiadiazole] (DMcT) is the most widely studied material and has a theoretical discharge capacity of 362 mAh / g. However, there is a problem in that depolymerization occurs during the reduction (discharge) process, so that electrical conductivity is low and it is soluble in a liquid electrolyte. To overcome this, there have been recent attempts to increase the charge capacity and electrical conductivity of electrode materials by making organic sulfides into conductive polymers and composites.

Such composites are prepared by chemical polymerization and co-electrodeposition of conductive polymers within inorganic hosts. In general, electropolymerized polyaniline has been reported to function as an effective electrocatalyst to increase the slow redox rate of DMcT. In another approach, it has been reported that a positive electrode material with improved electrochemical properties can be obtained by coating a conductive material on the surface of LiFePO ₄ with PDMcT.

Here, a conductive polypyrrole coated with PDMcT, which is an active material for a composite positive electrode, was manufactured into a thin film through the surface active template technology. As a positive electrode of a lithium secondary battery using a liquid electrolyte, a discharge capacity of 250 mAh / g was initially obtained, but gradually decreased.

As another redox system, poly (α, α'-dithio-3-amino-o-xylene) (PDTAn) has been proposed. PDTAn contains one 6-membered ring having an S-S bond in the side chain of aniline, which is obtained by electrochemical polymerization of α, α'-dithio-3-amino-o-xylene monomer. As a result of the charge / discharge test of Li / PDTAn cell, the initial capacity was 225 mAh / g and the charging efficiency was over 80% after the initial cycle.

In recent years, poly (2,2'-thiodianiline) (PDTDA), in which polymers are interconnected by SS bonds, has been synthesized to improve electrode performance, wherein the conjugated bond structure of the main chain is oxidized or reduced. Will be maintained. When a battery is manufactured using PDTDA as a cathode active material, it has a discharge capacity of 270 Ah / kg and an energy density of 675 Wh / kg, thereby making a very excellent battery.

However, the polymer is reduced in performance during repeated charge and discharge, which means that the recombination efficiency of the disulfide bond between the different polymers is not excellent. In addition, its redox reaction rate is lower than that of conventional materials at room temperature, resulting in poor electrical conductivity, resulting in very low power density when using batteries. In addition to the above, the product upon reduction of PDTDA has the disadvantage that it is soluble in the organic electrolyte solution.

Therefore, in order to solve the above problems in order to maximize the advantages of PDTDA, researches on various derivatives and various complexes of PDTDA have recently been conducted (Korean Patent 10-0454503).

In addition, polydiphenylamine (PDPA) is aniline substituted with N-aryl, and has different characteristics from polyaniline and other N-substituted aniline derivatives. PDPA differs from polyaniline and other N-substituted aniline derivatives in its various behaviors such as electrochemical properties, conductivity and electrochromic properties, which have para-diphenylene structures on both sides. Thus PDPA has the electrical properties of both polyaniline and poly (para-phenylene) in the backbone, where poly (para-phenylene) is a benzene polymer and is widely known for ion implantable organic cells. The materials are known to form rings of high orientation and complete co-planar structure with electrochemical intercalation properties similar to graphite.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems in the prior art, by introducing a N-aryl amine monomer having another conductivity to a dithiodioline (DTDA) derivative by chemical polymerization or electropolymerization method It is to provide a positive electrode material for an organic disulfur-based lithium secondary battery and a lithium secondary battery using the same that can significantly increase the capacity characteristics of the secondary battery.

In order to achieve the above object, in the present invention, a copolymer of a polydithioaniline repeating unit and an aryl amine polymer repeating unit or a composite of each polymer is prepared by chemical polymerization or electropolymerization and doped with a positive electrode active material ( Formula 1) was used, which has the property of intercalation-deintercalation of lithium ions.

[Formula 1]

Wherein X is H, Li, Na or K, Z is F, Cl, Br, I, ClO ₄ , PF ₆ , BF ₄ , CF ₃ SO ₃ , HSO ₄ or C1 ₂ H ₂₅ C ₆ H ₄ SO ₃ , k, k1 'and k2' are 0.01 to 0.5 as mole fractions, m is 0.05 to 0.95 as mole fractions, and n is 2 to 10,000 as repeat units.)

In order to achieve the above another object, there is provided a lithium secondary battery cell comprising a positive electrode manufactured by using a positive electrode composition, and an organic electrolyte filled between a standard electrode (SCE) and a counter electrode, and a positive electrode and a counter electrode. do. Here, the composition may be formed in the form of a film on the positive electrode current collector, the organic electrolyte may be used as long as it is generally known in the manufacturing field of a lithium battery, filled or separator with a liquid electrolyte between the positive electrode and the opposite electrode May be impregnated or a polymer electrolyte may be used.

At this time, the liquid electrolyte is ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, tetrahydrofuran, 2-methyltetrahydrofuran, dimethoxyethane, methyl formate, ethyl formate, gamma-butyrolactone Or an organic solvent composed of a mixture thereof, and in the case of a polymer electrolyte, polyethylene glycol, polypropylene glycol, polymethyl methacrylonitrile, polyethyl methacrylonite, or a mixture thereof.

In addition, the organic electrolyte in the above is lithium perchlorate (LiClO ₄ ), lithium triplate (LiCF ₃ SO ₃ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium trifluoromethane Lithium salts consisting of sulfonylimide (LiN (CF ₃ SO ₂ ) ₂ ), or mixtures thereof. The lithium salt may be used in an amount of 0.5 to 100% by weight, preferably 1 to 40% by weight, based on the weight of the organic solvent or polymer.

The method for preparing a cathode composition for a lithium secondary battery according to the present invention includes a copolymer of a dithioaniline repeating unit and an aryl amine repeating unit having the following structural formula (2), or an undoped polydie composed of a composite of each polymer. Synthesis of a thio dianiline derivative is performed.

[Formula 2]

(Wherein k, k1 'and k2' are 0.01 to 0.5 as mole fractions, m is 0.05 to 0.95 as mole fractions and n is 2 to 10,000 as repeat units).

Preparation of the undoped polydithiodianiline derivatives can be made by a chemical polymerization method and an electropolymerization method, doped with a repeating unit represented by the formula (1) by doping a conventional dopant to the undoped derivatives To form a polydithioaniline derivative.

Here, the usual dopant has a structure of the following formula (3).

[Formula 3]

AB

In Formula 3, A is H, Li, Na or K, B is F, Cl, Br, I, ClO ₄ , PF ₆ , BF ₄ , CF ₃ SO ₃ , HSO ₄ or C1 ₂ H ₂₅ C ₆ H ₄ Is SO ₃ . Such A is a cation and B is an anion and is then doped into the polydiothioaniline derivative and is added in the form of a corresponding acid during polymerization to be doped together with the polymerization, or after the polymerization is completed, is added in the form of an acid to doping It is also possible. Doped derivatives can be neutralized and dedoped by treatment with a base such as ammonia water.

The manufacturing and evaluation process of the positive electrode composition for a lithium secondary battery according to the present invention is as follows. Hereinafter, the preparation of the die sulfur-based polymer through chemical polymerization and electropolymerization of the positive electrode composition for a lithium secondary battery according to the present invention is described in the following Examples. This will be described in detail.

[Production and Evaluation of Anode Composition]

1) An organic disulfur-based polymer is prepared by polymerizing dithiodianiline derivatives and diphenylamine derivatives individually or together. In this case, a polydithioaniline derivative or a copolymer of a polydithioaniline and a polydiphenylamine derivative is obtained, and the polymer may be prepared by a chemical polymerization method and an electropolymerization method.

2) The organic die sulfur polymer prepared above is doped using a conventional dopant. As a result, the doped organic die sulfur-based polymer has electroactivity.

3) After coating the doped organic die-sulfur-based polymer prepared in the form of a film on a conventional positive electrode to prepare a lithium secondary battery consisting of an organic electrolyte located between the lithium-containing negative electrode and the positive electrode / negative electrode.

4) By analyzing the current value according to the potential change of the lithium secondary battery prepared by using Cyclic Voltammetry it is possible to know the specific peak current and the capacitance of the anodic / cathode.

The present invention can be carried out using a variety of materials under various conditions, the following examples are intended to help explain the invention and the scope of the present invention should not be limited by the following examples.

Analysis methods used in the following Examples and Comparative Examples are as follows.

[Analysis method]

1) Cyclic Voltammetry: This experiment is to measure the current value generated by redox reaction while changing the potential of the working electrode to the standard electrode (SCE) at a constant speed, and to know the electrochemical characteristics of the electrode material. Used. (EG & G PAR 283 Electrochemical Analyzer)

2) GPC (gel permeation chromatography): used to know the molecular weight and molecular weight distribution of the prepared polymer material (polystyrene basis).

3) Elemental analysis: It was used to know the content of the main element (S) in the polymerization product.

4) Fourier Transform Infrared (FT-IR) and Raman Spectroscopy: The purpose of this study was to determine the presence of core bonds in monomers and polymers.

5) Scanning electron microscope (SEM): To examine the morphology of the polymer.

In this experiment, 2,2'- dithiodianiline (Fluka), diphenylamine (Aldrich) as the monomer for the positive electrode composition, ammonium persulfate (Aldrich) as the oxidizing agent for polymerization, and sulfonic acid (Aldrich) as the doping solution G) was used.

Example 1 Chemical Polymerization Method

The organic disulfer polymer was prepared by chemically oxidizing polymerization with potassium peroxydisulfate (PDS) as an oxidizing agent, and the monomers used were 2,2'-dithiodianiline (DTDA) and diphenylamine (DPA). Was. Both monomers were added at a concentration of 50 mM DPA and 50 mM DTDA in 4M H ₂ SO ₄ solution and the temperature was cooled to 273K.

Then, a low temperature ammonium persulfate solution (100 mM) was added dropwise thereto for 20 minutes and stirred. After the addition, the mixture was further stirred for 1 hour while maintaining the cooling state, and the green precipitate thus formed was continuously filtered through the 4M H ₂ SO ₄ solution until it was colorless. Then, the resultant was vacuum dried at room temperature for 48 hours to obtain a polydithioaniline derivative.

Example 2 Electropolymerization Method

50 mM DPA and 50 mM DTDA were added to the 4 MH ₂ SO ₄ solution, followed by electropolymerization by continuously giving a potential cycle in the range of 0 to 900 mV (relative to the SCE electrode). As a result, a greenish film was deposited on the electrode surface and used after washing by flowing 4 MH ₂ SO ₄ .

Comparative Example 1 Chemical Polymerization Method

Except for not using the diphenylamine (DPA) in Example 1 polydithiodioline was prepared in the same manner.

Comparative Example 2 Electropolymerization Method

Except for not using diphenylamine (DPA) in Example 2, polydithio aniline was prepared in the same manner.

TABLE 1

TABLE 2

Table 1 summarizes the results of evaluating the redox behavior at a potential scan rate of 5 mV in 0.1 M LiClO ₄ acetonitrile using the positive electrode compositions prepared in Comparative Example 1 and Example 1. In the case of the positive electrode composition of Comparative Example 1, the anodic peak (E _pa ) appeared at 0.5V and 0.8V, respectively, and in the reverse potential scan, the cathodic peak (E _pc ) at 0.7V and 0.3V, respectively. happened. This significant difference in redox peak potential accounts for the slow redox reaction.

In contrast, for the positive electrode composition of Example 1, the difference between the peak potentials was much smaller, showing a gentle single anodical peak near 0.8V and a cathodic peak near 0.5V. This is because the interaction of PDPA and PDTDA shifts the positive cathodic peak to enable the redox reaction to occur effectively, thus increasing the peak current value. The above results are obtained through the electrocatalyst phenomenon.

In addition, in the case of Example 1, it can be seen that the value of the cathodic capacitance (Q _c ) and the anodic capacitance (Q _a ) is higher than that of Comparative Example 1, which is a decrease in inter-particle contact resistance and electrochemical activity The result is an increase in efficiency. In addition, the ratio (Q _c / Q _a ) of the cathodic capacitance and the anodic capacitance was close to 1 in Example 1, indicating an electrochemically excellent reversibility, whereas Comparative Example 2 was higher than 1. Large values indicate that only a fraction of the electrochemically oxidized PDTDA is reduced.

Table 2 shows the results of elemental analysis of the positive electrode compositions prepared in Example 1 and Comparative Example 1, 10.07% in Example 1 compared to the sulfur content (S) = 17.86% of Comparative Example 1, thereby SS after polymerization Show that the bond is maintained.

(A) of FIG. 1 is a CV graph during the electropolymerization reaction of 2,2'- dithio dianiline demonstrated in the comparative example 2. FIG. The potential ranged from 0 to 1.2 V relative to the SCE electrode, using a solution containing 50 mM of 2,2'- dithiodioline in 4M sulfonic acid. The potential cycle ran up to 100 times, with the anodic terminal voltage reaching 1.2V or higher.

The inset in (a) is the initial anodical potential scan, and a sharp peak occurred at 1.2 V, confirming that the disulfide bond is reduced to the ring-opened dithioate anion. Subsequent anodic scans showed a corresponding reduction peak of +0.7 V and the opposite scan of 0.45 V. A peak of +0.7 V indicates the redox reaction of the polyaniline side chain.

The redox-reduction of the polyaniline at the N site can be complemented by a self-doping / undoping process of the thiourate anion split by reduction of the SS bond. Sustained increase in peak current with the number of cycles indicates that poly (2,2'-diothiodianiline) (PDTDA) is being formed at the drive electrode, which gradually forms a green precipitate on the surface of the drive electrode. . The PDTDA film thus grown exhibits an electrical conductivity of 1.2 × 10 ⁻⁴ S.cm ⁻¹ .

FIG. 1B is a CV graph during the electropolymerization reaction of the 1,2 mixture of 2,2'-dithiodianiline (DTDA) and diphenylamine (DPA) described in Example 2. FIG. In the mixture solution, there was a sharp peak at 0.8 V relative to the SCE electrode (insertion) during the initial anodical potential scan, and two peaks of 0.75 V and 0.89 V were generated in the subsequent potential scan that proceeded up to 100 times. , Which represent oxidation of diphenylamine monomer and dithiolate anion, respectively. In the opposite scan, a gentle peak occurred near 0.57V.

Comparing the CV graphs, it can be seen that the case of (b) shows a higher redox peak current than when the 2,2′-diothiodianiline solution of (a) is electropolymerized. This increase in redox peak current is due to the polydiphenylamine formed when preparing a copolymer having 2,2'-dithiodianiline and diphenylamine together to promote the redox reaction of disulfide. The film of the grown copolymer showed an electrical conductivity of 2.8 x 10 ^-2 S.cm ^-1 , which is much higher than that of PDTDA (a), and thus the composite cathode material showed high electrochemical activity.

2 is a GPC graph of the positive electrode composition polymerized in Example 1, using dimethyl formamide (DMF) as a moving solvent and polystyrene (PS) was used as a reference material. PDI (Polydispersity index) = 1.3 from the chromatogram, the weight average molecular weight (Mw) was calculated to 118,000.

FIG. 3 shows Fourier-Transform Infrared of 2,2′-diothiodianiline (a), PDTDA (b) and PDTDA-PDPA copolymer (c) used in Examples 1-2 and Comparative Example 1. FIG. ) Spectrum. In spectrum (a) of the 2,2′-dithiodianiline monomer, NH 2 functional groups were identified from the peaks 3416 and 3326 cm ⁻¹ , which were not found in the copolymer with PDTDA. In (b), the CH bonds of the quinoid and benzoid rings were identified from the 1149 and 825 cm ^-1 peaks, and the C = C bonds of the benzoid and quinoid rings were confirmed at the peaks of 1502 and 1612 cm ^-1 . In (c), the C = C peak of the aromatic ring was shifted to 1485 and 1602 cm ^-1 , thereby confirming that the conjugate length increases when doping.

In addition, peaks of 750 and 465 cm ⁻¹ appeared in (b) and (c), which account for CS and SS bonds. In addition, in the case of (c), the absorption peak (1100 -1) of S = O did not appear, thereby indicating that the SS bond is maintained even after polymerization.

FIG. 4 is Raman spectra of 2,2′-dithiodianiline (a), PDTDA (b) and PDTDA-PDPA copolymer (c) used in Examples 1-2 and Comparative Example 1. FIG. In the case of 2,2'-dithiodianiline monomer (a), SS and CS bonds were identified at 526 and 640 cm ^-1 , and 525 cm ^-1 peak for PDTDA (b) and copolymer (c). SS binding was confirmed in.

FIG. 5 shows the morphology of the PDTDA and PDTDA-PDPA copolymers prepared in Comparative Example 1 and Example 1 by FESEM, and the similar morphology could be confirmed, and both had particles with a granule structure of 2 m in size.

The positive electrode composition developed for the lithium secondary battery developed in the present invention is composed of a new organic disulfer-based polymer, and specifically, by copolymerizing or polymerizing a dithiodianiline derivative and an N-aryl amine derivative chemically or electrochemically, respectively, It is a polymer which has a repeating unit which consists of a dithio dianiline derivative and N-aryl amine.

When the polymer is doped and used as an active material for a positive electrode, a split-recombination reaction of an organic disulfide bond proceeds reversibly as compared with a conventional conductive polymer, thereby increasing capacity retention characteristics according to the number of charge and discharge cycles. The performance is significantly improved.

Claims (7)

A positive electrode composition of a conductive polymer material containing a sulfur-sulfur bond composed of a copolymer of a polydithioaniline repeating unit of Formula 1 and an N-aryl amine derivative. [Formula 1]

Wherein X is H, Li, Na or K, Z is F, Cl, Br, I, ClO ₄ , PF ₆ , BF ₄ , CF ₃ SO ₃ , HSO ₄ or C ₁₂ H ₂₅ C ₆ H ₄ SO ₃ , k, k1 'and k2' are each 0.01 to 0.5 as molar ratios, m is 0.05 to 0.95 as molar ratios and n is 2 to 10,000 as repeating units). The method of claim 1, wherein the positive electrode composition is sulfur-, characterized in that the organic disulfur-based polymer composed of a copolymer of a polydithioaniline repeating unit of the formula (2) and an N- aryl amine derivative is doped with the formula (3) Anode composition of conductive polymer material containing sulfur bonds. [Formula 2]

(Wherein k, k1 'and k2' are each 0.01 to 0.5 as molar ratios, m is 0.05 to 0.95 as molar ratios and n is 2 to 10,000 as repeating units) [Formula 3] AB (A in Formula 3, A is H, Li, Na or K, B is F, Cl, Br, I, ClO ₄ , PF ₆ , BF ₄ , CF ₃ SO ₃ , HSO ₄ or C1 ₂ H ₂₅ C ₆ H ₄ SO ₃ ) A lithium secondary battery comprising a positive electrode in which a composition according to claim 1 is held in a positive electrode current collector, a negative electrode containing lithium, and an organic electrolyte filled between the positive electrode and the negative electrode. The lithium secondary battery according to claim 3, wherein the composition of claim 1 is coated on the cathode current collector in the form of a film. The lithium secondary battery of claim 3, wherein the organic electrolyte is impregnated in a separator inserted between the positive electrode and the negative electrode. The organic electrolyte according to any one of claims 3 to 5, wherein (a) ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, tetrahydrofuran, 2-methyltetrahydrofuran, dimethoxyethane, methyl formate, ethyl formate, gamma-butyrolactone, or Comprising organic solvents composed of mixtures thereof, or (b) A lithium secondary battery comprising a polymer polar solvent comprising polyethylene glycol, polypropylene glycol, polymethyl methacrylate, polyethyl methacrylate, or a mixture thereof. The organic electrolyte according to any one of claims 3 to 5, wherein the organic electrolyte is lithium perchlorate (LiClO ₄ ), lithium triplate (LiCF ₃ SO ₃ ), lithium hexafluorophosphate (LiPF ₆ ), or lithium tetrafluoro. A lithium secondary battery comprising a lithium salt consisting of borate (LiBF ₄ ), lithium trifluoromethanesulfonylimide (LiN (CF ₃ SO ₂ ) ₂ ), or a mixture thereof.

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