KR102217106B1 - Composition for polymer electrolyte and lithium secondary battery comprising the same - Google Patents

Abstract

The present invention relates to a single ion conductive polymer and a lithium secondary battery using the same, and specifically, a composition for a polymer electrolyte comprising a single ion conductive polymer having high ion conductivity and lithium ion mobility, and the cell performance is improved by including the same. It relates to a lithium secondary battery.

Description

Polymer electrolyte composition and lithium secondary battery including the same {COMPOSITION FOR POLYMER ELECTROLYTE AND LITHIUM SECONDARY BATTERY COMPRISING THE SAME}

The present invention relates to a composition for a polymer electrolyte and a lithium secondary battery including the same, and specifically, a composition for a polymer electrolyte comprising a single ion conductive polymer having high ionic conductivity and lithium ion mobility, and It relates to a lithium secondary battery with improved cell performance by including.

As energy storage technology application fields are expanded to cell phones, camcorders, notebook PCs, and electric vehicles, efforts for research and development of batteries are increasingly being concreted, and electrochemical devices are the field receiving the most attention in this respect.

In particular, according to the recent trend, many studies on lithium secondary batteries are being conducted due to the characteristics of miniaturization and weight reduction among electrochemical devices, and high energy density and discharge voltage.

A lithium secondary battery includes a positive electrode or negative electrode manufactured by using a material capable of intercalation and deintercalation of lithium ions as an active material, and is a medium that transfers charge between the positive electrode and the negative electrode. Liquid electrolyte or polymer It has an electrolyte.

Currently, a polyethylene oxide (poly(ethylene oxide); hereinafter abbreviated as "PEO")-based polymer electrolyte has been proposed as a polymer electrolyte used in lithium secondary batteries. However, in the case of a polymer electrolyte using PEO, while exhibiting a relatively high ionic conductivity (10 ^-4 S/cm) at a high temperature of 60°C or higher, there is a disadvantage in that the ionic conductivity decreases to 10 ^-8 S/cm at room temperature. In addition, it is known that most of the polymer electrolytes have lithium cation mobility as low as 0.2 to 0.4.

Accordingly, a method of introducing various additives capable of controlling the crystallinity of PEO, a polymer matrix, has been proposed to secure ionic conductivity at room temperature.

However, while the crystallinity is controlled when the additive is introduced, the glass transition temperature (Tg) is increased while the mechanical properties are weakened, or the size of the additives themselves affect the chain mobility of the PEO chain. It causes the disadvantage that the ionic conductivity of is rather lowered.

Accordingly, in order to commercialize a lithium secondary battery, it is necessary to develop a polymer electrolyte having high ionic conductivity and excellent interfacial stability with an electrode.

Korean Patent Publication No. 10-1607024 Korean Patent Publication No. 10-0541312

The present invention was devised to solve such a problem.

A first technical problem to be solved by the present invention is to provide a composition for a polymer electrolyte comprising a single ion conductive polymer having high ionic conductivity and lithium ion mobility.

In addition, a second technical problem to be solved of the present invention is to provide a solid polymer electrolyte membrane composed of the polymer electrolyte composition.

In addition, a third technical problem to be solved of the present invention is to provide an electrode composite composed of the polymer electrolyte composition.

In addition, a fourth technical problem to be solved of the present invention is to provide a lithium secondary battery with improved cell performance by including the composition for a polymer electrolyte.

In order to achieve the above object, in one embodiment of the present invention

A single ion conductive polymer including a unit represented by Formula 1 below; And

It provides a composition for a polymer electrolyte comprising at least one additive selected from the group consisting of ceramic electrolytes and inorganic particles.

[Formula 1]

In the above formula,

R is -CF ₂ -[CF(CF ₃ )] _m -[CF ₂ ] _n -, where m is an integer from 0 to 3, and n is an integer from 0 to 5,

R ₁ is -CF ₂ -(CF ₂ ) _o -, wherein o is an integer from 0 to 3,

X is H ⁺ or Li ⁺ ,

a and c represent the number of moles of the repeating unit,

the molar ratio of a:c is 1:1 to 10:1,

b is an integer of 0 or 1.

The weight average molecular weight (Mw) of the single ion conductive polymer may be 240 to 200,000, specifically 240 to 50,000.

In addition, the equivalent weight (EW) of the single ion conductive polymer is 300 to 880, specifically 650 to 880.

The single ion conductive polymer may include at least one unit selected from the group consisting of units represented by the following Chemical Formulas 1a to 1d.

[Formula 1a]

[Formula 1b]

[Formula 1c]

[Formula 1d]

In Formulas 1a to 1d,

X is H ⁺ or Li ⁺ ,

a and c represent the number of moles of the repeating unit,

The molar ratio of a:c is 1:1 to 10:1.

Further, the ceramic electrolyte is included in the additive is lanthanum lithium zirconate _{(Li 7 La 3 Zr 2 O} 12; LLZO), lithium aluminum germanium phosphate _{(Li 1 5 Al 0 5 Ge} 1 .5 (PO 4) 3.. ; LAGP), lithium aluminum titanium phosphate (LATP), lithium and lanthanum titanate (Li _0.5 La _0.5 TiO ₃ ; LLTO), lithium germanium phosphorus sulfide (LGPS), and a single material selected from the group consisting of lithium phosphorus sulfide or 2 It may contain a mixture of more than one species.

In addition, the inorganic particles included as the additives are Al ₂ O ₃ , BaTiO ₃ , SnO ₂ , CeO ₂ , SiO ₂ , TiO ₂ , Li ₃ PO ₄ , NiO, ZnO, MgO, Mg(OH) ₂ , CaO, ZrO ₂ , Ta ₂ O ₅ , Y ₂ O _{3 ,} Pb(Zr,Ti)O ₃ (PZT), Pb _1-x La _x Zr _1-y Ti _y O ₃ (PLZT), PB(Mg ₃ Nb _2/3 )O ₃ -PbTiO ₃ (PMN-PT) and hafnia (HfO ₂ ) It may include a single substance or a mixture of two or more selected from the group consisting of.

The weight ratio of the monoionic conductive polymer: additive in the polymer electrolyte composition may be 1:0.1 to 1:9, specifically 1:1 to 1:3.

The polymer electrolyte composition may further include a binder as necessary.

In addition, in the present invention, it is possible to provide a solid polymer electrolyte membrane constructed by using the composition for a polymer electrolyte of the present invention.

In addition, in the present invention, it is possible to provide an electrode composite composed of the polymer electrolyte composition.

The electrode composite may include a positive electrode composite or a negative electrode composite.

Specifically, the electrode composite includes an electrode current collector and an electrode mixture layer coated on the electrode current collector, and the electrode mixture layer may include an electrode active material slurry and a polymer electrolyte composition of the present invention.

Alternatively, the electrode composite may include an electrode current collector, an electrode mixture layer including an electrode active material slurry coated on the electrode current collector, and a coating layer including the polymer electrolyte composition of the present invention coated on the electrode mixture layer. have.

In addition, the present invention can provide a lithium secondary battery including a positive electrode, a negative electrode, and the solid polymer electrolyte membrane of the present invention.

In addition, the present invention includes a positive electrode, a negative electrode, and an electrolyte, and at least one of the positive electrode and the negative electrode may provide a lithium secondary battery including the electrode composite of the present invention.

According to an embodiment of the present invention, a composition for a polymer electrolyte comprising a single ion conductive polymer having high ionic conductivity and mobility of lithium ions is provided, and by using this, excellent ionic conductivity properties and interfacial stability with electrodes are provided. This is improved, and a solid polymer electrolyte membrane and/or an electrode composite in which concentration polarization is suppressed can be prepared. Therefore, it is possible to manufacture a lithium secondary battery with improved electrochemical stability and cell performance.

The following drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the contents of the present invention. It is limited and should not be interpreted.
1 to 3 are cross-sectional views schematically showing various embodiments of an electrode assembly including a solid polymer electrolyte membrane according to an embodiment of the present invention.
4 and 5 are cross-sectional views schematically showing various embodiments of an electrode assembly including an electrode composite according to an embodiment of the present invention.
6 and 7 are graphs comparing rate characteristics of a lithium secondary battery according to Experimental Example 2.
8 is a graph showing a measurement result of cycle life evaluation of a lithium secondary battery according to Experimental Example 3.
9 is a graph showing the results of a resistance evaluation experiment of a lithium secondary battery according to Experimental Example 4.

Hereinafter, the present invention will be described in more detail to aid understanding of the present invention. In this case, the terms or words used in the specification and claims should not be interpreted as being limited to a conventional or dictionary meaning, and the inventor appropriately defines the concept of the term in order to describe his own invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that it can be done.

Polymer electrolytes are being developed in terms of greatly improving the stability of lithium secondary batteries, but they still show low ionic conductivity and insufficient mechanical properties when compared to liquid electrolyte/separator systems.

In order to improve this, studies have recently been attempted on a single ion conductive polymer electrolyte in which anions are fixed to a polymer main chain and only Li ions contribute to ion conduction.

Single ion conductive polymer electrolyte means that only one ion is a polymer that contributes to conductivity, and by including an anion as a stationary phase to limit the movement of anions, concentration polarization under a direct electric field is prevented, thereby reducing ionic conductivity. It is known to be able to maintain a relatively stable current density in the battery by preventing. Moreover, since there is no risk of ignition compared to the case of using a liquid electrolyte, a single ion conductive polymer electrolyte is known to be suitable for lithium batteries for electric vehicles and large storage batteries.

Currently, monoionic conductive polymer electrolytes are solvent-free monoionic conductive polymers mainly based on ionomers such as polyethylene oxide, polypropylene oxide, and polyether, whose main polymer chain has ionic dissociation ability.Acrylate series for reinforcing mechanical properties It is produced by a method of introducing a polymer or urethane-based polymer into a matrix.

However, when the acrylate-based polymer or urethane-based polymer is introduced as a matrix, the number of anions that can be immobilized on the polymer main chain is limited, so the concentration of the charge carrier itself is lowered, and the dissociation degree of the salt fixed on the main chain is low. Compared to the conventional polymer electrolyte using a lithium salt, the ionic conductivity is lowered, and thus the situation has not been put into practical use.

Accordingly, in the present invention, a single ion conductive polymer based on'ionomer' consisting of a repeating unit that is not ionic and a repeating unit containing a small amount of ions, and at least one additive among ceramic electrolytes and inorganic particles is included. By providing a composition for a polymer electrolyte, a solid polymer electrolyte capable of realizing an effect of improving ionic conductivity by securing uniformity of movement of Li cations, an effect of improving interfacial stability with an electrode, and suppressing concentration polarization, and a secondary battery comprising the same Can be manufactured.

Specifically, in one embodiment of the present invention

A single ion conductive polymer containing a unit represented by the following formula (1); And

It provides a composition for a polymer electrolyte comprising at least one additive selected from the group consisting of ceramic electrolytes and inorganic particles.

[Formula 1]

In the above formula,

R is -CF ₂ -[CF(CF ₃ )] _m -[CF ₂ ] _n -, where m is 0 or an integer of 1 to 3, and n is 0 or an integer of 1 to 5 Is,

R ₁ is -CF ₂ -(CF ₂ ) _o -, wherein o is 0 or an integer of 1 to 2,

X is H ⁺ or Li ⁺ ,

a and c represent the number of moles of the repeating unit,

the molar ratio of a:c is 1:1 to 10:1,

b is an integer of 0 or 1.

The weight average molecular weight (Mw) of the single ion conductive polymer may be 240 to 200,000, specifically 240 to 50,000.

The weight average molecular weight (Mw) can be measured using ¹⁹ F-NMR (nuclear magnetic resonance) (solvent, acetone-d ⁶ , CCl ₃ F).

In addition, the equivalent weight (EW) of the single ion conductive polymer is 300 to 880, specifically 650 to 880, and more specifically 650 to 800.

At this time, the EW is a sulfonate group (SO ₃ ^-) means a weight (gram) of the polymer necessary to put on 1 mol (ionomers). At this time, when the EW of the single ion conductive polymer exceeds 880, since the polymer weight per 1 mole of the sulfonate group is large, the equivalent amount of sulfonate groups is relatively reduced, so that the ion conductivity effect may be reduced. When the EW is 300 or less, it may be difficult to secure sufficient mechanical properties.

Specifically, the EW can be calculated through Equations 1 and 2 below.

[Equation 1]

[Equation 2]

In the above formula,

IEC stands for ion exchange capacity,

The titrated mole is = 1000 mmol.

That is, first, a solid polymer electrolyte membrane is prepared, and then the electrolyte membrane is cut to about 1 × 1 cm ² and dried (vacuum/oven) at 80° C. for 24 hours (overnight). Subsequently, the dried electrolyte membrane was weighed, and the dried polymer electrolyte membrane was added to a saturated NaCl aqueous solution, followed by stirring for 24 hours. After adding 1-2 drops of a phenolphthalein (pH 8.3-10 pink) solution to the stirred solution, a 0.1N NaOH standard solution is slowly added, and the appropriate measurement result is substituted in Equation 1 to obtain IEC. have. Next, the calculated IEC is substituted into Equation 2, and the equivalent weight (EW) can be obtained from the obtained measured dry weight (g).

In the composition for a polymer electrolyte of the present invention, the single ion conductive polymer including the unit represented by Formula 1 is a main chain composed of carbon in which a hydrogen atom is completely substituted with a fluorine atom, and a side chain including a fluoroalkoxy sulfonate substituent. Since it has an ionomer structure, an anion can be used as a fixed phase and only a cation source can be provided in the battery. Accordingly, the degree of freedom of cations in the electrolyte may be increased, thereby improving ionic conductivity. Moreover, since a separate electrolyte salt is not included, a decrease in interfacial stability due to concentration polarization due to anion decomposition of the conventional electrolyte salt can be suppressed.

Moreover, as described below, when a liquid electrolyte is additionally included as needed during the manufacture of a secondary battery, the single ion conductive polymer can serve as a cation source instead of the electrolyte salt contained in the liquid electrolyte. It is possible to reduce the content of the electrolyte salt contained. Therefore, by suppressing side reactions accompanying anions of the electrolyte salt, it is possible to improve the cycle life characteristics and stability of the secondary battery under high temperature and high voltage.

The single ion conductive polymer may include at least one unit selected from the group consisting of units represented by the following Formulas 1a to 1d.

[Formula 1a]

[Formula 1b]

[Formula 1c]

[Formula 1d]

In Formulas 1a to 1d,

X is H ⁺ or Li ⁺ ,

a and c represent the number of moles of the repeating unit,

The molar ratio of a:c is 1:1 to 10:1.

In addition, the composition for a polymer electrolyte of the present invention according to an embodiment may further include at least one additive selected from the group consisting of the ceramic electrolyte and inorganic particles in order to improve bulk ionic conductivity.

The ceramic electrolyte is a representative example of lanthanum lithium zirconate _{(Li 7 La 3 Zr 2 O} 12; LLZO), lithium aluminum germanium phosphate _{(Li 1 5 Al 0 5 Ge} 1 .5 (PO 4) 3;.. LAGP ), lithium aluminum titanium phosphate (LATP), lithium and lanthanum titanate (Li _0.5 La _0.5 TiO ₃ ; LLTO), lithium germanium phosphorus sulfide (LGPS), and lithium phosphorus sulfide. Mixtures are mentioned.

In addition, the inorganic particles are representative examples of Al ₂ O ₃ , BaTiO ₃ , SnO ₂ , CeO ₂ , SiO ₂ , TiO ₂ , Li ₃ PO ₄ , NiO, ZnO, MgO, Mg(OH) ₂ , CaO, ZrO ₂ , Ta ₂ O ₅ , Y ₂ O _3, Pb(Zr,Ti)O ₃ (PZT), PB(Mg ₃ Nb _2/3 )O ₃ -PbTiO ₃ (PMN-PT) and hafnia (HfO ₂ ) A single substance or a mixture of two or more selected from the group consisting of may be mentioned.

In particular, when a ceramic electrolyte is included as the additive, concentration polarization can be more effectively suppressed when the cell is driven due to an increase in a lithium cation transport rate (Li transference number) and an increase in lithium concentration in the electrolyte.

In the polymer electrolyte composition, the weight ratio of the monoionic conductive polymer: the additive may be 1:0.1 to 1:9, specifically 1:1 to 1:5.

If the weight ratio of the additive exceeds 9 with respect to the single ion conductive polymer, since the content of the single ion conductive polymer is relatively reduced, it is difficult to obtain an effect of improving ionic conductivity and a good interface resistance between the active material and the electrolyte, and is less than 0.1. On the back, the effect of reducing the interface resistance is insignificant. In particular, the additive is preferably included in a ratio of 1:5 or less in order to effectively prevent an increase in the interfacial resistance between the electrode and the polymer electrolyte membrane.

In the composition for a polymer electrolyte according to an embodiment, a small amount of a binder may be optionally mixed in order to improve mechanical properties such as dispersing power and adhesion to an electrode or a separator.

The binder may include at least one selected from the group consisting of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl chloride, polyvinylpyrrolidone, polyvinyl alcohol, Teflon, and styrene butadiene rubber as representative examples thereof, Specifically, it may include polyvinylidene fluoride.

The binder may be included in a small amount in the polymer electrolyte composition, and specifically, may be included in an amount of about 5% by weight or less, specifically about 2% by weight or less based on the total content of the polymer electrolyte composition.

In addition, in an embodiment of the present invention, a solid polymer electrolyte membrane formed using the polymer electrolyte composition may be provided.

At this time, the solid polymer electrolyte membrane of the present invention is prepared in a film-like solid form by evaporating an organic solvent when manufacturing a secondary battery to be described later, and then as a freestanding film on one surface of the electrode or at the interface between the electrode and the separator. Can be introduced.

The solid polymer electrolyte membrane may be prepared in the form of a film, film or sheet having a thickness of 200 μm or less, for example, 0.1 to 100 μm, for example, 1 to 40 μm. At this time, in order to prepare a solid polymer electrolyte in the form of a sheet, film, or membrane, a mixed solution is prepared by dissolving the polymer electrolyte composition in an organic solvent, and then spin coating, roll coating, curtain coating, It can be prepared by coating and drying using a known method such as extrusion, casting, screen printing, and inkjet printing.

The organic solvent used in preparing the solid polymer electrolyte membrane is an organic solvent such as N-methylpyrrolidone (NMP), acetone, dimethylacetamide, or dimethylformaldehyde, an inorganic solvent such as water, or The mixture may be included as a main solvent, and the solvent may be removed in the subsequent drying step.

Specifically, the solid polymer electrolyte membrane may be disposed at the interface between the anode and the separator or the interface between the cathode and the separator within the structure of the electrode assembly (see FIGS. 1 and 2 to be described later), or on the anode and the anode. It may be coated to act as a freestanding separator in the form of a membrane film instead of a separator (see FIG. 3 to be described later). In this case, the separator may not be included as an essential component in the lithium secondary battery.

In addition, in an embodiment of the present invention, an electrode composite composed of the polymer electrolyte composition may be provided.

In this case, the electrode composite may be a positive electrode composite or a negative electrode composite.

The electrode composite may include an electrode current collector and an electrode mixture layer coated on the electrode current collector, and the electrode mixture layer may include an electrode active material slurry and a polymer electrolyte composition of the present invention.

The electrode composite may be prepared by mixing the electrode active material slurry and the polymer electrolyte composition of the present invention, and then coating and drying the same on an electrode current collector.

In this case, the polymer electrolyte composition may be included in an amount of 0.1 to 40 parts by weight, specifically 3.0 to 30 parts by weight, based on 100 parts by weight of the electrode active material slurry.

If the content of the polymer electrolyte composition exceeds 40 parts by weight, the content of the active material may be relatively decreased and the capacity may be reduced. If the content is less than 0.1 parts by weight, the electrode interface resistance reduction and concentration polarization suppression effect may be insignificant.

In this way, when the polymer electrolyte composition is mixed in the electrode active material slurry to prepare an electrode composite, the polymer electrolyte composition is evenly disposed and present in the electrode layer, thereby resulting in an effect of uniformizing the conductivity (resistance) of the electrode. That is, in the case of a liquid electrolyte, due to the movement of lithium cations during charging and discharging, there are cases where the resistance is increased due to a shortage of cations at the electrolyte interface temporarily. This phenomenon may be worsened when the thickness of the electrode increases. On the other hand, in the case of using a solid polymer electrolyte, even if the electrode thickness (loading amount) increases, concentration polarization can be suppressed, thereby preventing an increase in interfacial resistance with the electrode. Particularly, in the case of forming a composite by introducing a polymer electrolyte component in the electrode into the electrode in preparation for the case of introducing a solid polymer electrolyte membrane as described above, concentration polarization can be more effectively suppressed, thereby further enhancing the safety of the secondary battery. .

In addition, the electrode composite may include an electrode current collector, an electrode mixture layer including an electrode active material slurry coated on the electrode current collector, and a coating layer including the polymer electrolyte composition of the present invention coated on the electrode mixture layer. I can.

That is, the electrode composite may be prepared by dispersing the polymer electrolyte composition of the present invention in a binder solvent to prepare a coating solution, and then coating it on the surface of the previously prepared electrode mixture layer, followed by drying.

At this time, the coating method may be a conventional coating method, specifically, a known technique such as spin coating, roll coating, curtain coating, extrusion, casting, screen printing, inkjet printing, and the like.

The solvent may include an organic solvent such as N-methylpyrrolidone (NMP), acetone, dimethylacetamide, or dimethylformaldehyde, an inorganic solvent such as water, or a mixture thereof as a main solvent, and the solvent is the It can be removed in a subsequent drying step.

In addition, in an embodiment of the present invention

It is possible to provide a lithium secondary battery including a positive electrode, a negative electrode, and the solid polymer electrolyte membrane of the present invention.

In addition, the present invention may provide a lithium secondary battery comprising a positive electrode, a negative electrode, and an electrolyte, and at least one of the positive electrode and the negative electrode includes the electrode composite of the present invention.

The lithium secondary battery may optionally further include a separator.

At this time, various embodiments of the electrode assembly according to the embodiment of the present invention are schematically shown in FIGS. 1 to 5. At this time, the electrode assembly of the present invention is not limited to this embodiment.

First, in FIGS. 1 to 3, various embodiments of an electrode assembly including a solid polymer electrolyte membrane constituted by using the composition for a polymer electrolyte of the present invention are shown.

That is, as shown in FIG. 1, the electrode assembly of the present invention may have a solid polymer electrolyte membrane 13 interposed at an interface between the porous separator 15-1 and the cathode 11. To this end, the electrode assembly may be manufactured by sequentially stacking the first porous separator 15, the negative electrode 11, the solid polymer electrolyte membrane 13, the second porous separator 15-1, and the positive electrode 17. have.

Alternatively, as shown in FIG. 2, the electrode assembly of the present invention may have a solid polymer electrolyte membrane 23 interposed at the interface between the porous separator 25-1 and the anode 27,

To this end, the electrode assembly may be manufactured by sequentially stacking a first porous separator 25, a negative electrode 21, a second porous separator 25-1, a solid polymer electrolyte membrane 23, and an anode 17. have.

According to another example, as shown in FIG. 3, in the electrode assembly of the present invention, a solid polymer electrolyte membrane 33 may be interposed at an interface between the anode 37 and the cathode 31 in place of the separator. To this end, the electrode assembly may be manufactured by laminating a first solid polymer electrolyte membrane 33, a cathode, a second solid polymer electrolyte membrane 33-1, and an anode 37.

The first and second solid polymer electrolytes (13, 23, 33, 33-1) are prepared by dissolving the composition for a polymer electrolyte of the present invention in an organic solvent such as N-methylpyrrolidone to prepare a mixed solution. It may be coated on a substrate and dried to form a film, and then the substrate may be removed and then introduced as a separate type of film.

The thickness of the solid polymer electrolyte may be in the range of 5 to 200 μm.

The interfacial resistance of the solid polymer electrolyte may be measured using a VMP3 device manufactured by Bio-Logic, and may be about 0 to 200 kΩ at 25°C.

In this case, in the lithium secondary battery of the present invention, the positive electrode and the negative electrode may be manufactured by a conventional method known in the art. For example, after preparing a slurry by mixing and stirring a solvent, a binder, a conductive material, and a dispersant as necessary in the electrode active material, it is applied (coated) to the current collector of a metal material, compressed, and dried to prepare an electrode. have.

Specifically, the positive electrode may be prepared by coating a positive electrode active material slurry in which a positive electrode active material, optionally a conductive material, a binder, and a solvent are mixed on a positive electrode current collector, followed by drying and rolling.

The positive electrode current collector is generally made to have a thickness of 3 μm to 500 μm. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or the surface of aluminum or stainless steel. For example, those treated with carbon, nickel, titanium, silver, or the like may be used.

The positive electrode current collector may increase the adhesion of the positive electrode active material by forming fine irregularities on the surface thereof, and various forms such as films, sheets, foils, nets, porous bodies, foams, and nonwoven fabrics are possible.

The positive electrode active material is a compound capable of reversible intercalation and deintercalation of lithium, and specifically, may include at least one metal such as cobalt, manganese, nickel, or aluminum, and a lithium composite metal oxide containing lithium. have. More specifically, the lithium composite metal oxide is a lithium-manganese oxide (eg, LiMnO ₂ , LiMn ₂ O _4, etc.), a lithium-cobalt oxide (eg, LiCoO _2, etc.), a lithium-nickel oxide (for example, LiNiO ₂ and the like), lithium-nickel-manganese-based oxide (for example, LiNi _1-Y Mn _Y O ₂ (where, 0 <Y <1), LiMn _2-z Ni _z O ₄ ( here, 0 <Z <2) and the like), lithium-nickel-cobalt oxide (e.g., LiNi _1-Y1 Co _Y1 O ₂ (here, 0 <Y1 <1) and the like), lithium-manganese-cobalt oxide (e. g., LiCo _1-Y2 Mn _Y2 O ₂ (here, 0 <Y2 <1), LiMn 2 - z1 Co z1 O 4 ( here, 0 <Z1 <2) and the like), lithium-nickel -Manganese-cobalt oxide (e.g., Li(Ni _p Co _q Mn _r1 )O ₂ (here, 0<p<1, 0<q<1, 0<r1<1, p+q+r1= 1) or Li(Ni _p1 Co _q1 Mn _r2 )O ₄ (here, 0<p1<2, 0<q1<2, 0<r2<2, p1+q1+r21=2), etc.), or lithium- Nickel-cobalt-transition metal (M) oxide (e.g., Li(Ni _p2 Co _q2 Mn _r3 M _S2 )O ₂ (wherein M is Al, Fe, V, Cr, Ti, Ta, Mg and Mo) Is selected from the group consisting of, and p2, q2, r3, and s2 are atomic fractions of independent elements, respectively, 0<p2<1, 0<q2<1, 0<r3<1, 0<s2<1, p2+q2 +r3+s2=1 is), etc.), and any one or two or more compounds may be included. Among them, the lithium composite metal oxide is LiCoO ₂ , LiMnO ₂ , LiNiO ₂ , lithium nickel manganese cobalt oxide (e.g., Li(Ni _0.6 Mn _0.2 Co _0.2 ) O ₂ in that it can increase the capacity characteristics and stability of the battery. , Li (Ni _0.5 Mn _0.3 Co _0.2) O ₂ or _{Li (Ni 0.8 Mn 0.1 Co 0.1} ) O 2 ), or lithium nickel cobalt aluminum oxide (for _{example, LiNi 0. 8 Co 0.} 15 Al 0. 05 O ₂ etc.), etc., in consideration of the remarkable improvement effect by controlling the type and content ratio of the constituent elements forming the lithium composite metal oxide, the lithium composite metal oxide is Li(Ni _0.6 Mn _0.2 Co _0.2 )O ₂ , Li(Ni _0.5 Mn _0.3 Co _0.2 )O ₂ , Li(Ni _0.7 Mn _0.15 Co _0.15 )O ₂ or Li(Ni _0.8 Mn _0.1 Co _0.1 )O _2, etc., any one or a mixture of two or more of them may be used. have.

The positive electrode active material may be included in an amount of 80% to 99% by weight based on the total weight of the solid content in the positive electrode active material slurry.

The conductive material is typically added in an amount of 1 to 30% by weight based on the total weight of the solid content in the positive electrode active material slurry.

Such a conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery, for example, graphite; Carbon-based substances such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; Conductive fibers such as carbon fibers and metal fibers; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives may be used. Specific examples of commercially available conductive materials include acetylene black-based Chevron Chemical Company, Denka Singapore Private Limited, Gulf Oil Company, etc.), Ketjenblack, EC series (Armak Company), Vulcan XC-72 (Cabot Company) and Super P (Timcal).

The binder is a component that aids in bonding of the active material and the conductive material and bonding to the current collector, and is typically added in an amount of 1 to 30% by weight based on the total weight of the solid content in the positive electrode active material slurry. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoro. Ethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluorine rubber, and various copolymers.

The solvent may include an organic solvent such as NMP, and may be used in an amount having a desirable viscosity when the positive electrode active material and optionally a binder and a conductive material are included. For example, it may be included so that the solid content concentration in the positive electrode active material slurry is 50% by weight to 95% by weight, preferably 70% by weight to 90% by weight.

In addition, the negative electrode may be prepared by applying a negative electrode active material slurry in which a negative electrode active material, optionally a conductive material, a binder, and a solvent are mixed on a negative electrode current collector, followed by drying and rolling.

The negative electrode current collector is generally made to have a thickness of 3 μm to 500 μm. Such a negative electrode current collector is not particularly limited as long as it has conductivity without causing chemical changes to the battery, for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel. For the surface treatment with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloys, etc. may be used. In addition, like the positive electrode current collector, it is possible to enhance the bonding strength of the negative electrode active material by forming fine irregularities on the surface thereof, and may be used in various forms such as films, sheets, foils, nets, porous bodies, foams, and nonwoven fabrics.

The negative electrode active material may include carbon such as lithium metal, lithium alloy, or lithium metal oxide such as lithium titanium oxide (LTO), non-graphitized carbon, and graphite-based carbon; Li _x1 Fe ₂ O ₃ (0≤x1≤1), Li _x2 WO ₂ (0≤x2≤1), Sn _x3 Me _{1 - x3} Me' _y O _z (Me: Mn, Fe, Pb, Ge; Me' : Al, B, P, Si, elements of groups 1, 2, and 3 of the periodic table, halogen, metal complex oxides such as 0<x3≦1;1≦y≦3;1≦z≦8); Silicon-based alloys; Tin-based alloys; SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , GeO, GeO ₂ , Bi ₂ O ₃ , Bi ₂ O ₄ , And metal oxides such as Bi ₂ O ₅ ; Alternatively, a conductive polymer such as polyacetylene may be used together. As the lithium alloy, an alloy composed of lithium and at least one metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, Ra, Al, and Sn may be used.

The negative active material may be included in an amount of 60 to 97% by weight, preferably 80 to 97% by weight, based on the total weight of the solid content in the negative active material slurry.

In addition, the conductive material is not particularly limited as long as it has conductivity without causing side reactions with other elements of the secondary battery. For example, natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, channel black, Furnace black, lamp black, thermal black, carbon nanotube, fullerene, carbon fiber, metal fiber, carbon fluoride, aluminum, nickel powder, zinc oxide, potassium titanate, titanium oxide and a single product selected from the group consisting of polyphenylene derivatives or A mixture of two or more of these may be used.

The conductive material may be added in an amount of about 0.05 to 3% by weight based on the total weight of the solid content in the negative active material slurry.

The binder is for maintaining the molded body by binding active material particles, and acrylonitrile-butadiene rubber, styrene-butadiene rubber (SBR), hydroxy ethyl cellulose, vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co -HFP), polyvinylidene fluoride, polyvinyl alcohol, starch, polyacrylonitrile, hydroxypropyl cellulose, regenerated cellulose, polymethyl methacrylate, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene , Polyacrylic acid, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, and a single substance selected from the group consisting of polytetrafluoroethylene (PTFE), or a mixture of two or more thereof.

The binder may be included in an amount of about 0.5 to 3% by weight based on the total weight of the solid content in the negative active material slurry. At this time, if it is less than 0.5% by weight, it is difficult to secure electrode adhesion, and if it exceeds 3% by weight, electrode resistance may increase.

The solvent may contain water, an organic solvent such as NMP, alcohol, etc., and the viscosity of the electrode active material, binder, conductive material, etc. is dissolved and dispersed in consideration of the coating thickness and production yield of the electrode active material slurry. It can be used in any amount. For example, it may be included so that the solid content concentration in the total electrode active material slurry including the negative active material, the binder, the conductive material and the cellulose-based compound is 50% to 95% by weight, preferably 70% to 90% by weight.

In addition, the separator selectively introduced into the lithium secondary battery serves to block internal short circuits of both electrodes and impregnate the electrolyte, and includes polyolefin-based polymers such as polypropylene having chemical resistance and hydrophobic properties; A composite porous separator in which an inorganic material is added to a porous separator substrate; It may be a sheet made of glass fiber or polyethylene, or a nonwoven fabric. Specifically, the separator may be a conventional porous polymer film, that is, polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film having two or more layers thereof, and a polyethylene/polypropylene two-layer separator, polyethylene/polypropylene/polyethylene 3 It goes without saying that a mixed multilayer membrane such as a layer separation membrane and a polypropylene/polyethylene/polypropylene three layer separation membrane may be used. Alternatively, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high melting point glass fiber, polyethylene terephthalate fiber, or the like may be used, but is not limited thereto.

The pore diameter of the porous separator is generally 0.01 to 50 μm, and the porosity may be 5 to 95%. In addition, the thickness of the porous separator may generally range from 5 to 300 μm.

In addition, FIGS. 4 and 5 show other embodiments of an electrode assembly including an electrode composite configured using the composition for a polymer electrolyte of the present invention.

That is, as shown in FIG. 4, in the electrode assembly of the present invention, the negative electrode composite 49 may be interposed at an interface between the first porous separator 45 and the second porous separator 45-1.

To this end, the electrode assembly may be manufactured by sequentially stacking a first porous separator 45, a negative electrode composite 49, a second porous separator 45-1, and an anode 47.

The negative electrode composite 49 may be prepared by coating a negative active material slurry and a negative electrode mixture layer (not shown) including the polymer electrolyte composition of the present invention on a negative current collector (not shown).

Alternatively, as shown in FIG. 5, the electrode assembly of the present invention may have a positive electrode composite 59 interposed on the second porous separator 55-1.

To this end, the electrode assembly may be manufactured by sequentially stacking the first porous separator 55, the negative electrode 51, the second porous separator 55-1, and the positive electrode composite 59.

The positive electrode composite 59 may be prepared by coating a positive electrode mixture layer (not illustrated) including a positive electrode active material slurry and a polymer electrolyte composition of the present invention on a positive electrode current collector (not shown).

At this time, the positive electrode composite and the negative electrode composite may be prepared by a conventional method known in the art. For example, an electrode active material slurry and the composition for a polymer electrolyte of the present invention are mixed, and if necessary, a binder, a conductive material, and a dispersant are mixed and stirred to prepare a slurry, and then applied to a current collector (not shown) of a metal material. After (coating), compressing, and drying, a positive electrode composite or negative electrode composite can be prepared.

In this case, the polymer electrolyte composition may be included in an amount of 0.1 to 40 parts by weight, specifically 3.0 to 30 parts by weight, based on 100 parts by weight of the electrode active material slurry.

If the content of the polymer electrolyte composition exceeds 40 parts by weight, the content of the active material may be relatively decreased and the capacity may be reduced. If the content is less than 0.1 parts by weight, the electrode interface resistance reduction and concentration polarization suppression effect may be insignificant.

Alternatively, in another embodiment of the present invention, the electrode composite of the present invention forms an electrode mixture layer (not shown) by coating an electrode active material slurry on an electrode current collector (not shown), and then the electrode mixture layer (not shown) It may be prepared by coating the polymer electrolyte composition of the present invention on top and drying it.

In addition, the lithium secondary battery of the present invention is manufactured by storing an electrode assembly including a solid polymer electrolyte membrane and/or an electrode composite in a case to lower the cell driving temperature, and then optionally additionally injecting a liquid electrolyte before sealing. You may.

The liquid electrolyte includes an electrolyte salt and a non-aqueous organic solvent.

The electrolyte salt may be used, without limitation, those which are commonly used in a lithium secondary battery electrolyte, such as an anion include Li ^+, and with the positive ions ^{F -, Cl -, Br -} , I -, NO 3 -, ^{_{N (CN) 2 -, BF}} 4 -, ClO 4 -, AlO 4 -, AlCl 4 -, PF 6 -, SbF 6 -, AsF 6 -, BF 2 C 2 O 4 -, BC 4 O 8 -, ( ^{_{CF 3) 2 PF 4 -,}} (CF 3) 3 PF 3 -, (CF 3) 4 PF 2 -, (CF 3) 5 PF -, (CF 3) 6 P -, CF 3 SO 3 -, C 4 _{^{F 9 SO 3 -, CF 3}} CF 2 SO 3 -, (CF 3 SO 2) 2 N -, (F 2 SO 2) 2 N -, CF 3 CF 2 (CF 3) 2 CO -, (CF 3 SO _{^{2) 2 CH -, CF 3}} (CF 2) 7 SO 3 -, CF 3 CO 2 -, CH 3 CO 2 -, SCN - , at least one selected from the group consisting of ^- and _{(CF 3 CF 2 SO 2)} 2 N It can contain one. The electrolyte salt may be used alone or in combination of two or more as necessary.

The electrolyte salt may be used alone or in combination of two or more as necessary. The electrolyte salt may be appropriately changed within a range that is usually usable, but may be included in the electrolyte at a concentration of 0.8 M to 2 M in order to obtain an optimum effect of forming a film for preventing corrosion on the electrode surface.

In addition, the non-aqueous organic solvent is not particularly limited as long as it is a commonly used organic solvent, and representative examples thereof include cyclic carbonate, linear carbonate, lactone, ether, ester, sulfoxide, acetonitrile, lactam, ketone, and the like.

Examples of the cyclic carbonate include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), fluoroethylene carbonate (FEC), and the like, and examples of the linear carbonate include diethyl carbonate (DEC), dimethyl carbonate. (DMC), dipropyl carbonate (DPC), ethylmethyl carbonate (EMC), and methyl propyl carbonate (MPC). Examples of the lactone include gamma butyrolactone (GBL), and examples of the ether include dibutyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane, 1,2-diethoxyethane and the like. Examples of the ester include ethyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, butyl propionate, and the like. In addition, the sulfoxide includes dimethyl sulfoxide, and the lactam includes N-methyl-2-pyrrolidone (NMP), and the ketone includes polymethylvinyl ketone. In addition, a halogen derivative of the organic solvent can also be used. These organic solvents can be used alone or in combination.

At this time, when the liquid electrolyte is impregnated on the surface of the solid polymer electrolyte membrane of the present invention, the single ion conductive polymer is impregnated with the liquid to form a gel polymer electrolyte, and the additive is present in the gel polymer electrolyte as a solid electrolyte. At this time, the ionic conductivity (σ) of the polymer electrolyte is at room temperature, that is, at a temperature of 25°C, exceeding 2.0×10 ^-4 S/cm, specifically 3.0×10 ^-4 S/cm to 2.0×10 ^-2 S/cm of lithium It can have ionic conductivity.

The ion conductivity can be measured using an impedance measurement analysis system, and specifically, it can be measured under the conditions of AC method (1 MHz to 100 mHz) and Amplitude (10 mV) through a VMP3 device of Bio-Logic.

The appearance of the lithium secondary battery of the present invention prepared as described above is not particularly limited, but may be a cylindrical shape using a can, a square shape, a pouch type, or a coin type.

Hereinafter, examples will be described in detail to describe the present invention in detail. However, the embodiments according to the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. Embodiments of the present invention are provided to more completely describe the present invention to those of ordinary skill in the art.

Example

Example One.

The ionomer of Formula 1a (a:c molar ratio is 1:1, weight average molecular weight (Mw) 10,000), LATP (average particle diameter (D50) 300 nm), and binder (PVDF) of 2:3:0.25 in an NMP solvent A coating solution was prepared by mixing in a weight ratio, and then coated on a substrate and dried to prepare a 50 μm-thick solid polymer electrolyte membrane.

Comparative Example 1.

In Example 1, a solid polymer electrolyte membrane having a thickness of 50 μm was prepared in the same manner as in Example 1, except that the ceramic electrolyte was not included.

Experimental example

Experimental example One.

For the solid polymer electrolyte membrane specimens prepared in Example 1 and Comparative Example 1, the ionic conductivity was measured in the AC method (1 MHz to 100 mHz) and Amplitude (10 mV) conditions through the VMP3 equipment of Bio-Logic. The measured ionic conductivity results are shown in Table 1 below.

In addition, a liquid electrolyte solution (EC/EMC=4/6 wt%, 1M LiPF ₆ ) was impregnated into the solid polymer electrolyte membrane specimen to form a gel polymer electrolyte in which a liquid was impregnated in a portion. Subsequently, it was measured in the AC method (1MHz to 100mHz) and Amplitude (10mV) conditions through the Bio-Logic's VMP3 equipment. The measured ionic conductivity results are shown in Table 1 below.

In addition, the electrochemical stability was measured by Linear Sweep Voltammetry (LSV). The results are shown in Table 1 below.

25℃ ion conductivity
(S/cm) Oxidation current (A),
60℃, 5V Example 1 Before impregnation of liquid electrolyte 8.0×10 ^-5 4.0×10 ^-5 After impregnation of liquid electrolyte 5.5×10 ^-4 - Comparative Example 1 Before impregnation of liquid electrolyte 4.0×10 ^-7 9.0×10 ^-5 After impregnation of liquid electrolyte 2.0×10 ^-4 -

Referring to Table 1, it can be seen that the solid polymer electrolyte prepared in Example 1 has relatively improved ionic conductivity compared to the solid polymer electrolyte of Comparative Example 1 that does not include a ceramic electrolyte.

In addition, when the solid polymer electrolyte prepared in Example 1 was impregnated with a liquid electrolyte, it was confirmed that the oxidation stability was further improved by securing an ionic conductivity of 5.5×10 ^-4 S/cm and an oxidation current of 4.0×10 ^-5 . have.

On the other hand, the polymer electrolyte of Comparative Example 1 that did not contain a ceramic electrolyte was measured in a gel state by introducing a liquid electrolyte, and as a result, the ionic conductivity was relatively low and the oxidation current was 9.0 × 10 ^-5 , so that the oxidation stability was relatively low. Can be seen.

Example 2. (Secondary battery containing negative electrode composite)

5.0V class as the positive electrode active material a lithium nickel-manganese composite oxide _{(Lithium Nickel Manganese complex Oxide:.} . LiNi 0 5 Mn 1 5 O 4, LNMO) compound, a conductive material of carbon black, the PVDF as a binder, 92 weight ratio of 4:04 A positive electrode active material slurry was prepared by adding it to a furnace solvent, N-methyl-2 pyrrolidone (NMP).

Subsequently, the positive electrode active material slurry was coated on an aluminum (Al) thin film having a thickness of 20 μm, followed by drying and rolling to prepare a positive electrode 47 having a thickness of 30 μm.

An anode active material slurry was prepared by mixing an anode active material (Li ₄ Ti ₅ O ₁₂ ), a conductive material (Super-P), and a binder (PVDF) in an NMP solvent in a weight ratio of 85:5:10, and an ionomer of Formula 1a (a The molar ratio of :b is 1:1, weight average molecular weight (Mw) 10,000) and LATP (average particle diameter (D50) 300nm) are mixed in a weight ratio of 1:2.5 to prepare a composition for a polymer electrolyte, and then the negative active material slurry 100 A coating solution was prepared by mixing 7.5 parts by weight of a polymer electrolyte composition based on parts by weight.

Subsequently, the coating solution was coated on an aluminum foil having a thickness of 20 μm and then rolled and dried to prepare a negative electrode composite 49 (see FIG. 4).

A negative electrode composite 49 including the polymer electrolyte composition, a second polyolefin separator 45-1, and the prepared positive electrode 47 were sequentially placed on a first polyolefin-based separator 45 having a thickness of 20 μm. By stacking, an electrode assembly was manufactured.

After storing the electrode assembly in a pouch-type battery case, 0.5M LiPF ₆ An electrolyte solution (ethylene carbonate (EC)/ethylmethyl carbonate (EMC) = 30/70 wt%) was injected to prepare an LNMO/LTO high voltage battery (full cell).

Comparative example 2

In Example 2, when preparing the negative active material slurry, a high voltage battery was manufactured in the same manner as in Example 2, except that the composition for a polymer electrolyte was not included.

Example 3. (Secondary battery containing positive electrode composite)

As a cathode active material _{(LiNi 0 5 Mn 1 5 O} 4, LNMO..), Carbon black, a binder in NMP solvent for PVDF 91: 4: mixed in a weight ratio of 5 to prepare a positive electrode active material slurry, and the ionomer of the formula 1a ( The molar ratio of a:b is 1:1, weight average molecular weight (Mw) 10,000) and LATP (average particle diameter (D50) 300nm) are mixed in a weight ratio of 1:2 to prepare a composition for a polymer electrolyte, and then the positive electrode active material slurry A coating solution was prepared by mixing 7.5 parts by weight of a polymer electrolyte composition based on 100 parts by weight.

The coating solution was coated on an aluminum foil having a thickness of 20 μm, then rolled and dried to prepare a positive electrode composite 59 having a thickness of 20 μm (see FIG. 5).

The cathode 51 was made of Li metal.

The anode 51, the second polyolefin-based separator 55-1, and the cathode composite 59 including the polymer electrolyte composition are sequentially stacked on the first polyolefin-based separator 55 having a thickness of 20 μm to obtain an electrode. The assembly was prepared.

After storing the electrode assembly in a pouch-type battery case, 0.5M LiPF ₆ An electrolyte solution (ethylene carbonate (EC)/ethylmethyl carbonate (EMC) = 30/70 wt%) was injected to prepare an LNMO/LTO high voltage battery (full cell).

Comparative example 3.

In Example 3, when preparing the positive electrode active material slurry, a high voltage battery was manufactured in the same manner as in Example 3, except that the composition for a polymer electrolyte was not included.

Experimental example 2.

Each secondary battery prepared in Example 2 and Comparative Example 2 was fixed at 25°C and 45°C, respectively, with a charging rate of 0.5C, and a discharge rate of 0.5C to 5C, while at 3.35V-2.0V. The rate characteristics were evaluated by observing the change in dose, and the results are shown in FIGS. 6 and 7.

Referring to FIGS. 6 and 7, in the case of a secondary battery into which a negative electrode composite including a polymer electrolyte is introduced, as shown in FIG. 6, as shown in FIG. 6, as well as 25° C., as shown in FIG. It can be seen that the resistance decreases at, and the discharge capacity decreases even when the C-rate increases.

Experimental example 3.

Each secondary battery prepared in Example 2 and Comparative Example 2 was cycled at 45° C. at a charge and discharge rate of 1 C/1 C to measure their charge and discharge capacity, and the results are shown in FIG. 8.

Referring to FIG. 8, it can be seen that in the case of the secondary battery of Example 2 in which the negative electrode composite including the polymer electrolyte was introduced, the life retention rate according to the number of cycles was improved compared to the lithium secondary battery of Comparative Example 2.

Experimental example 4. Battery resistance evaluation experiment

The lithium secondary batteries prepared in Example 3 and Comparative Example 3 were each discharged at 23° C. at 1C, and their discharge capacity and discharge curve are shown in FIG. 9.

Referring to FIG. 9, in the case of a lithium secondary battery having a positive electrode composite including a polymer electrolyte, as in Example 3 of the present invention, polarization is suppressed compared to the lithium secondary battery of Comparative Example 3, thereby reducing resistance. Accordingly, it can be seen that the capacity increases at the same rate .

11, 21, 31, 51: cathode
13, 23, 33: (first) solid polymer electrolyte membrane
33-1: second solid polymer electrolyte membrane
15, 25, 45, 55: first porous separator
15-1,25-1, 45-1, 55-1: second porous separator
17, 27, 37, 47: anode
49: negative electrode composite
59: positive electrode composite

Claims (15)

A single ion conductive polymer containing a unit represented by the following formula (1); And
Containing a ceramic electrolyte,
The single ion conductive polymer: the weight ratio of the ceramic electrolyte is 1:0.1 to 1:9 of the polymer electrolyte composition:
[Formula 1]

In the above formula,
R is -CF ₂ -[CF(CF ₃ )] _m -[CF ₂ ] _n -, where m is an integer from 0 to 3, and n is an integer from 0 to 5,
R ₁ is -CF ₂ -(CF ₂ ) _o -, wherein o is an integer from 0 to 3,
X is H ⁺ or Li ⁺ ,
a and c represent the number of moles of the repeating unit,
the molar ratio of a:c is 1:1 to 10:1,
b is an integer of 0 or 1.
The method according to claim 1,
The weight average molecular weight (Mw) of the single ion conductive polymer is 240 to 200,000 polymer electrolyte composition.
The method according to claim 1,
The weight average molecular weight (Mw) of the single ion conductive polymer is 240 to 50,000 polymer electrolyte composition.
The method according to claim 1,
EW (Equivalent Weight, equivalent weight) of the single ion conductive polymer is a polymer electrolyte composition that is 300 to 880.
The method according to claim 1,
The single ion conductive polymer is a polymer electrolyte composition comprising at least one unit selected from the group consisting of units represented by the following formulas 1a to 1d.
[Formula 1a]

[Formula 1b]

[Formula 1c]

[Formula 1d]

In Formulas 1a to 1d,
X is H ⁺ or Li ⁺ ,
a and c represent the number of moles of the repeating unit,
The molar ratio of a:c is 1:1 to 10:1.
The method according to claim 1,
The ceramic electrolyte comprises a single substance or a mixture of two or more selected from the group consisting of lithium lanthanum zirconate, lithium aluminum germanium phosphate, lithium aluminum titanium phosphate, lithium and lanthanum titanate, lithium germanium phosphorus sulfide and lithium phosphorus sulfide. The polymer electrolyte composition.
delete delete A solid polymer electrolyte membrane constructed using the composition for a polymer electrolyte of claim 1.
An electrode composite composed of the composition for a polymer electrolyte of claim 1.
The method of claim 10,
The electrode composite is an electrode composite that is a positive electrode composite or a negative electrode composite.
The method of claim 10,
The electrode composite includes an electrode current collector and an electrode mixture layer coated on the electrode current collector,
The electrode mixture layer is an electrode composite comprising the electrode active material slurry and the polymer electrolyte composition of claim 1.
The method of claim 11,
The electrode composite includes an electrode current collector, an electrode mixture layer coated on the electrode current collector, and a coating layer including the polymer electrolyte composition of claim 1 coated on the electrode mixture layer.
A lithium secondary battery comprising a positive electrode, a negative electrode, and the solid polymer electrolyte membrane of claim 9.
Including a positive electrode, a negative electrode and an electrolyte,
At least one electrode of the positive electrode and the negative electrode is a lithium secondary battery comprising the electrode composite of claim 10.

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