KR102539971B1 - Solid Electrolyte Composition, Preparation Method thereof, and Battery Comprising the Same - Google Patents

Abstract

The present invention is a polymer; an inorganic additive whose surface is modified with an acrylic polymer containing a polysiloxane side chain; And a solid electrolyte composition containing a lithium salt, a method for preparing the same, and a battery including the same. According to the present invention, lithium ion conductivity can be greatly improved compared to conventional electrolytes by modifying and using the surface of an inorganic additive mixed with a polymer in a solid electrolyte composition. Due to this remarkably high lithium ion conductivity, the solid electrolyte composition of the present invention can be used in various types of lithium batteries including lithium ion batteries, lithium sulfur batteries, and lithium air batteries.

Description

Solid Electrolyte Composition, Preparation Method thereof, and Battery Comprising the Same}

The present invention relates to a solid electrolyte, a method for preparing the same, and a battery including the same.

As interest in energy storage technology continues to grow, the field of application expands to the energy of mobile phones, tablets, laptops and camcorders, and even electric vehicles (EVs) and hybrid electric vehicles (HEVs). Research and development of chemical elements is gradually increasing. Electrochemical devices are the field that has received the most attention in this respect, and among them, the development of lithium secondary batteries capable of charging and discharging has become a focus of attention. To this end, research and development on the design of new electrodes and batteries are being conducted.

Such a lithium secondary battery is largely composed of a positive electrode, a negative electrode, a separator, and an electrolyte, and among them, a liquid electrolyte accounts for a large proportion as an electrolyte for a lithium secondary battery. The liquid electrolyte has the advantage of providing high ion conductivity, but also has problems of deteriorating the stability of the battery due to high vapor pressure, possibility of leakage to the outside of the battery, and low ignition point.

Solid electrolytes have been developed to solve these problems of liquid electrolytes. Solid electrolytes can be roughly divided into inorganic solid electrolytes, polymer solid electrolytes, and composite solid electrolytes. However, the inorganic solid electrolyte has a problem of interfacial resistance with the electrode, and the polymer solid electrolyte has a problem of low lithium ion conductivity. Accordingly, a composite solid electrolyte was developed, and it was expected that the composite solid electrolyte would solve the disadvantages of the inorganic solid electrolyte and the polymer solid electrolyte at the same time. Existing composite solid electrolytes have mixed metal-organic frameworks (MOF), hybrid nanofibers, silica, etc. into polymers, but they have not yet obtained satisfactory lithium ion conductivity values for battery applications. am.

An object of the present invention is to provide a solid electrolyte composition having excellent lithium ion conductivity, a method for preparing the same, and a battery including the same.

According to one aspect of the present invention, a polymer; an inorganic additive whose surface is modified with an acrylic polymer containing a polysiloxane side chain; and a solid electrolyte composition containing a lithium salt.

According to another aspect of the present invention, there is provided a method for preparing the above-described solid electrolyte composition, comprising the step of (a) mixing an acrylic polymer having a polysiloxane side chain with an inorganic additive to prepare a surface-modified inorganic additive.

According to another aspect of the present invention, an anode; a cathode facing the anode; and an electrolyte layer comprising the solid electrolyte composition according to claim 1 between the positive electrode and the negative electrode.

According to the present invention, the surface of an inorganic additive mixed with a polymer in a solid electrolyte composition is treated with an acrylic polymer containing a polysiloxane side chain to modify the surface to have hydrophobicity, so that the inorganic additive can be uniformly dispersed in the polymer. In addition, the lithium ion conductivity of the solid electrolyte composition of the present invention can be greatly improved compared to conventional electrolytes by using such a surface-modified inorganic additive. Due to this remarkably high lithium ion conductivity, the solid electrolyte composition of the present invention can be used in various types of lithium batteries including lithium ion batteries, lithium sulfur batteries, and lithium air batteries.

Figure 1 is a graph showing the ionic conductivities (σ) measured at temperatures ranging from 20 to 70 °C using MZ-CPE and SPE modified with various contents of M-SSZ-13.
Figure 2 shows the AC impedance spectrum of 5% MZ-CPE measured at temperatures ranging from 20 to 70 °C.
Figure 3 shows the results of evaluating the electrochemical stability of SPE and 5% MZ-CPE by linear sweep voltammetry (LSV).
Figure 4 shows a DC polarization curve measured using 5% MZ-CPE to determine the Li ion transmission rate.
5 shows Nyquist plots obtained by EIS measurements before and after polarization using 5% MZ-CPE at 60°C.
6 is a graph showing the cycle performance of [Li/electrolyte film/Li] coin cells at a current density of 0.1 mA (0.09 mA/cm ² ) at 60° C., (a) is a result using SPE and (b) is This is the result using 5% MZ-CPE.
7 is a graph showing the EIS impedance spectrum of 5% MZ-CPE divided before and after cycling at 60° C. for 250 hours.
8 shows high-resolution XPS F 1s spectra of SPE and 5% MZ-CPE.
9 shows cyclic voltammograms of 5% MZ-CPE measured at 60° C. and scan rates of 5 mV/s and 10 mV/s using [SS/5% MZ-CPE/Li] coin cells. .
10 shows the rate capability of [Li/5% MZ-CPE/LFP] cells at various rates from 0.1 C to 1 C at 60°C.
Figure 11 shows the measured charge / discharge performance of the [Li / 5% MZ-CPE / LFP] cell at 0.1 C.
Figure 12 shows the cycling performance of [Li / 5% MZ-CPE / LFP] cells at 0.1 C.

Hereinafter, the present invention will be described in detail.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the present invention. Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

Throughout the specification, when a part “includes,” “includes,” or “has” a certain component, it means that it may further include other components unless otherwise specifically defined.

Terms such as first and second are used to distinguish one component from another, and the components are not limited by the aforementioned terms.

When a part of a layer, film, etc. is said to be "above/on" or "below/below" another part, it means that the other part is "directly on/on" or "directly below/below" the other part. This includes not only cases where they are in contact with each other, but also cases where other parts exist in the middle. Conversely, when a part is said to be “directly above/on” or “directly below/below” another part, it means that there is no other part in the middle.

The spatially relative terms "below", "below", "above", "above", etc. facilitate the correlation of one element or element with another element or element as shown in the drawings. can be used to describe Spatially relative terms should be understood as encompassing different orientations of elements in use or operation in addition to the orientations shown in the figures. For example, when an element shown in the figure is inverted, an element described as “below” another element may be placed “above” the other element. Thus, the exemplary term “below” may include directions of both below and above. Elements may also be oriented in other orientations, and thus spatially relative terms may be interpreted according to orientation.

1. Solid Electrolyte Composition

According to one aspect of the present invention, a polymer; an inorganic additive whose surface is modified with an acrylic polymer containing a polysiloxane side chain; and a solid electrolyte composition containing a lithium salt.

According to one embodiment of the present invention, the acrylic polymer including the polysiloxane side chain may be represented by Formula 1 or Formula 2 below:

[Formula 1]

[Formula 2]

In Formula 1 and Formula 2,

Each R may be identical to or different from each other, and is a straight-chain alkyl group having 1 to 8 carbon atoms, wherein R may be the same, and may be a straight-chain or branched-chain alkyl group having 1 to 4 carbon atoms, more specifically, a methyl group, ;

R ¹ is a straight-chain or branched-chain alkenyl group having 2 to 8 carbon atoms;

R ² is a hydrogen atom or a -COOR' group, wherein R' is a hydrogen atom or a saturated or unsaturated straight-chain, branched-chain or cyclic aliphatic alkyl group having 1 to 22 carbon atoms;

R ³ is -COOR' when c is 1, -(CH ₂ )-COOR' or a methyl group when c is 0, wherein R' is as defined above;

At least a portion of R ² and at least a portion of R ³ have terminal groups functionalized with a hydroxyl group (—OH group);

a is a numerical value from 0 to 10;

c is 0 or 1;

m is a numerical value selected so that the weight average molecular weight of the polysiloxane side chain is in the range of 1,000 to 30,000;

m+n is a numerical value selected so that the weight average molecular weight of the acrylic polymer containing the polysiloxane side chain is in the range of 2,000 to 200,000.

According to one embodiment of the present invention, in the acrylic polymer including the polysiloxane side chain (hereinafter also referred to as an acrylic polymer), the fraction of the polysiloxane side chain in the acrylic polymer may be 5 to 25% by weight. Specifically, the fraction of the polysiloxane side chain may be 7.5 to 12.5% by weight.

In addition, according to another embodiment of the present invention, the weight average molecular weight of the polysiloxane side chain may be in the range of 1,000 to 30,000, specifically in the range of 3,000 to 10,000. In Formula 1 and Formula 2, m is a numerical value selected so that the weight average molecular weight of the polysiloxane side chain is within the above range, wherein m is a polysiloxane side chain having the same length as the polymer main chain or a polysiloxane side chain having a different length. The values may be the same or different from each other for each monomer unit of the polymer backbone to link the mixture.

In addition, according to another embodiment of the present invention, the weight average molecular weight of the acrylic polymer is in the range of 2,000 to 200,000, specifically in the range of 3,000 to 100,000, more specifically in the range of 4,000 to 80,000, and even more specifically in the range of 5,000 to 60,000.

Also, according to another embodiment of the present invention, the acrylic polymer may exhibit a hydroxyl value in the range of 5 to 100 mg KOH/g. The hydroxyl value may be specifically in the range of 10 to 80 mg KOH/g, more specifically in the range of 20 to 60 mg KOH/g.

For more details on the acrylic polymer represented by Formula 1 or Formula 2 above, reference may be made to US Patent No. 7,122,599. An example of such a suitable acrylic polymer is BYK-SILCLEAN 3700 available from BYK-Chemie. It is thought that the hydroxyl functional group in the acrylic polymer interacts with the inorganic additive to modify the hydrophilic surface of the inorganic additive to be hydrophobic.

According to one embodiment of the present invention, the inorganic additive included in the solid electrolyte composition may be zeolite.

Zeolite is a crystalline aluminosilicate in which silicon and aluminum atoms are combined with oxygen atoms in a coordinated structure, and the type is classified according to the structure and a unique code is assigned to it. According to one embodiment of the present invention, the zeolite may have a CHA framework structure, and in particular, it may have a Si/Al ratio of 5 or more, that is, a high silica content, among zeolites having the CHA framework structure. there is.

According to one embodiment of the present invention, the zeolite, particularly the zeolite having a CHA framework structure, has a chemical formula of a unit cell constituting the zeolite Q _x Na _y Al _2.4 Si _33.6 O ₇₂ z H ₂ It may be represented by O (1.4 < x < 27) (0.7 < y < 4.3) (1 < z < 7) (Q is N , N , N -1-trimethyladamantammonium). An example of a suitable zeolite is SSZ-13.

According to one embodiment of the present invention, the inorganic additives including zeolite may be included in an amount of 20% by weight or less, specifically, 10% by weight or less based on the total weight of the solid electrolyte composition. As can be seen in the examples described later, the ionic conductivity of the battery can be greatly improved by using the inorganic additive of the present invention in an amount within the above range.

According to one embodiment of the present invention, the polymer included in the solid electrolyte composition may be an ion conductive polymer. The polymer is not particularly limited as long as it is an ion conductive polymer, and may include, for example, at least one selected from the group consisting of hydrocarbon-based polymers, fluorine-based polymers, and polyether-based polymers.

The hydrocarbon-based polymer is selected from sulfonated polyimide, sulfonated polysulfone, polyphenylene ether-based electrolyte membrane, sulfonated polybenzoxazole, ketal group-containing polymer, sulfonic acid ester-containing polymer, and polybenzonitrile copolymer. Including one or more, but not limited thereto.

Examples of the fluorine-based polymer include polytetrafluoroethylene (PTFE) and Nafion, but are not limited thereto.

The polyether-based polymer includes, but is not limited to, polyethylene oxide (PEO: poly(ethylene oxide)).

According to one embodiment of the present invention, in the solid electrolyte composition of the present invention, the polymer may be a polyether-based polymer, specifically polyethylene oxide (PEO).

According to one embodiment of the present invention, the solid electrolyte composition contains a lithium salt.

The lithium salt is a material that serves as a source of lithium ions to enable the operation of a basic lithium secondary battery and promotes the movement of lithium ions between a positive electrode and a negative electrode. According to one embodiment of the present invention, the lithium salt may be included in an amount of 50% by weight or less based on the weight of the total solid electrolyte composition. When the lithium salt is added in an amount exceeding 50% by weight, not only positive ion lithium ions but also negative ion salts may be present in the solid electrolyte to prevent movement of lithium ions and decrease ionic conductivity.

The lithium salt is not particularly limited as long as it contains lithium ions, but according to an embodiment of the present invention, the lithium salt is LiPF ₆ , LiBF ₄ , lithium bis(fluorosulfonyl)imide (Li[(FSO ₂ ) ₂ N], Li[FSI]), lithium bis(trifluoromethanesulfonyl)imide (Li[(CF ₃ SO ₂ ) ₂ N], Li[TFSI]), lithium bisoxalate borate (Li[ (O ₂ C ₂ O ₂ ) ₂ B], Li[BOB]), LiClO ₄ , LiBF ₃ (CF ₃ ), LiBF ₃ (C ₂ F ₅ ), LiBF ₃ (C ₃ F ₇ ), LiBF ₃ (C ₄ F ₉ ), LiC(SO ₂ CF ₃ ) ₃ , CF ₃ SO ₂ OLi, CF ₃ COOLi, and R"COOLi (R" is an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a naphthyl group) selected from the group consisting of It may be at least one species.

2. Manufacturing method of solid electrolyte composition

According to another aspect of the present invention, there is provided a method for preparing the above-described solid electrolyte composition, comprising the step of (a) mixing an acrylic polymer having a polysiloxane side chain with an inorganic additive to prepare a surface-modified inorganic additive.

According to one embodiment of the present invention, the manufacturing method includes (b) mixing the surface-modified inorganic additive and a lithium salt; and (c) adding and mixing a polymer to the mixture obtained in step (b).

Step (a) may be performed by dispersing the acrylic polymer in an appropriate solvent to obtain a solution, dispersing an inorganic additive therein, and then mixing. After the mixing, filtration and drying may be performed to obtain an inorganic additive surface-modified with the acrylic polymer of the present invention.

Step (b) may be performed by dispersing and mixing the surface-modified inorganic additive and lithium salt in an appropriate solvent. The type of the solvent is not particularly limited as long as it has no reactivity to the inorganic additive or lithium salt and can disperse them well, and examples thereof include acenonitrile.

The step (c) may be performed by adding and dispersing a polymer to the mixture of the inorganic additive and the lithium salt to obtain a solution, and mixing the solution, for example, by ball-milling. The solution after mixing may be dried after removing the solvent.

3. Batteries

According to one aspect of the invention, a positive electrode; a cathode facing the anode; and an electrolyte layer comprising the solid electrolyte composition according to claim 1 between the positive electrode and the negative electrode.

According to one embodiment of the present invention, the battery may be a lithium ion battery, a lithium sulfur battery, or a lithium air battery.

According to another embodiment of the present invention, the battery may further include a current collector provided on each surface of the positive electrode and the negative electrode. According to another embodiment of the present invention, the battery may further include a current collector provided on a surface opposite to a surface of the positive electrode facing the negative electrode. The current collector serves to collect electrons generated by the electrochemical reaction of the positive electrode active material or the negative electrode active material or to supply electrons necessary for the electrochemical reaction. In general, metals such as copper or aluminum may be used, but stainless steel , aluminum, nickel, titanium, calcined carbon, copper; stainless steel surface treated with carbon, nickel, titanium or silver; aluminum-cadmium alloy; Non-conductive polymer surface treated with a conductive material; Alternatively, a conductive polymer or the like may be used, but is not limited thereto.

In the manufacture of the battery, parts, cases, configurations and manufactures known in the art may be applied. For example, mixing and preparing a positive electrode and a negative electrode, forming a coating and slurry, and coating the current collector; Assembling the anode, electrolyte, and cathode may be included.

4. Examples

Hereinafter, the present invention will be described in more detail with reference to embodiments of the present invention. Since the examples are presented for explanation of the invention, the present invention is not limited thereto.

[Preparation Example 1: Preparation of surface-modified inorganic additive]

As the acrylic polymer of the present invention, OH-functional silicone modified polyacrylate (BYK-SILCLEAN 3700) was used, and zeolite SSZ-13 (manufactured by ACS materials) was used as an inorganic additive.

BYK-SILCLEAN 3700 was dissolved in acetone at a concentration of 0.2 g/L to obtain a solution. Thereafter, SSZ-13 was dispersed in the obtained solution and subjected to ultrasonic treatment to obtain a solution having a concentration of 5 g/L. Then, the solution was magnetically stirred for 3 hours. The precipitate was filtered through a membrane filter with a pore size of 0.2 μm and dried at 120° C. to obtain surface-modified SSZ-13 (hereinafter referred to as M-SSZ-13).

[Preparation Example 2: Preparation of Solid Electrolyte Composition]

After dispersing M-SSZ-13 and Li[TFSI] (lithium bis(fluorosulfonyl)imide, manufactured by Alfa Aesar) in acetonitrile solvent (15 mL), through magnetic stirring at 700 rpm for 1 hour mixed. Then, PEO (Mw = 1000000, from Alfa Aesar) was added and dispersed for 24 hours to prepare a homogeneous solution. The content of each component used is shown in [Table 1] below.

[Table 1]

The obtained solution was ball-milled for 48 hours. The solution was poured into a Teflon vessel (60 mL) and air dried at room temperature in an Ar environment. Thereafter, the solid electrolyte composition (film form) was obtained by drying at 60° C. for 24 hours to remove residual solvent.

[Comparative Example 1: Solid electrolyte composition using inorganic additives without surface modification]

A solid electrolyte composition was prepared in the same manner as in Preparation Example 2, except that SSZ-13 as it was not surface-modified according to the present invention was used in an amount of 5%. This was termed 5% CPE .

[Comparative Example 2: Solid Electrolyte Composition Using No Inorganic Additives]

A solid electrolyte composition was prepared in the same manner as in Preparation Example 2, except that no inorganic additive was used. This was named SPE .

[Evaluation example]

[Evaluation Example 1: Ion Conductivity Measurement Test]

Ionic conductivities (σ) were obtained at various temperatures (20, 30, 40, 50, 60, and 70 °C) using MZ-CPE and SPE modified with various contents of M-SSZ-13, and the results It is shown in Figure 1 and [Table 2] below.

[Table 2]

As can be seen from Table 2, MZ-CPE exhibited a higher overall ionic conductivity than SPE. In particular, the ionic conductivity of the 5% MZ-CPE sample showed the highest ionic conductivity in all temperature ranges regardless of temperature. As the content of M-SSZ-13 in 5% MZ-CPE increased, the ionic conductivity slightly decreased compared to 5% MZ-CPE.

[Evaluation Example 2: Electrochemical Stability Test of 5% MZ-CPE]

The electrochemical stability of SPE and 5% MZ-CPE was evaluated by linear sweep voltammetry (LSV), and the results are shown in FIG. 3 .

LSV was performed at 60° C. at a scan rate of 5 mV/s using a coin cell with a [SS/5% MZ-CPE/Li] structure. Here, SS was used as the working electrode and Li was used as both the counter and reference electrodes, and measurements were made over a potential range of 2.6 to 6.0 V (vs. Li/Li ⁺ ). As can be seen in FIG. 3, 5% MZ-CPE exhibited a potential window up to 5.42 V (vs. Li/Li ⁺ ), compared to 4.6 V of PEO-SSZ-13, 4.75 V of PEO-LLZTO, and SPE. is remarkably high. This shows an improvement in the electrochemical stability of 5% MC-CPE.

[Evaluation Example 3: Charge Transfer Efficiency of Electrolyte]

The Li ion transfer rate (transference number) (t _Li+ ) is an indicator of the charge transfer efficiency of the electrolyte. Figure 4 shows a DC polarization curve measured using 5% MZ-CPE to determine the Li ion transmission rate. EIS measurements were performed before and after polarization. A Nyquist plot obtained for 5% MZ-CPE at 60° C. is shown in FIG. 5 . The Li ion transmission rate was calculated according to Equation 1 below using the AC impedance (FIG. 2) and DC polarization results (FIG. 5).

[Equation 1]

In Equation 1, Io represents an initial current value, Is represents a steady-state current value, Δν represents polarization voltage, and Ro and Rs represent charge transfer resistance before and after polarization, respectively.

t _Li+ was 0.85 for 5% MZ-CPE, which is 1.7 times higher than 0.50 for CPE. For SPE, it is 0.25. Such a significant improvement in t _{Li +} is due to M-SSZ-13, which is a favorable environment for the M-SSZ-13 to be more stably dispersed in a solvent and Li + adsorbed into the nanopores on the surface of M-SSZ-13. This is thought to be due to the formation of That is, this excellent Li ion transmission rate confirms the strong adsorption of Li+ on the M-SSZ-13 surface. In addition, since high Li ion transmission rate is a critical factor in reducing polarization, it is expected to enhance the cycling performance of solid-state Li metal batteries.

[Evaluation Example 4: Interface compatibility test]

In solid-state Li metal cells, interfacial stability and ionic conductivity have a significant impact on the improvement of performance and durability. Accordingly, the long-term interfacial compatibility of SPE and 5% MZ-CPE was compared, and at this time, a coin cell with a symmetrical [Li/electrolyte film/Li] structure was used. A charge/discharge current density of 0.09 mA/cm ² at 60° C. for 1 hour was used. The results are shown in FIG. 6 (a) and FIG. 6 (b).

As can be seen in (a) of FIG. 6, the potential value of SPE slightly increased from 0.50 V to 0.70 V during the first 10 hours, increased slightly with time, then gradually decreased, and reached approximately 0.27 V at 103 hours, After 103 hours, the potential suddenly decreased to 0.015 V, and after 227 hours, the cell died.

On the other hand, in the case of 5% MZ-CPE, as can be seen in (b) of FIG. 6, as in SPE, the potential slightly increased from 0.2 V to 0.27 V until the first 10 hours, but after that, unlike SPE, 250 The potential value remained stable over time. After slowly decreasing to 0.26 V after 46 hours, the value of approximately 0.26 V was maintained until after 250 hours, and there was no short-circuit phenomenon. This means that there is resistance to Li dendrite formation.

Meanwhile, FIG. 7 shows EIS impedance spectra measured before and after cycling 5% MZ-CPE at 60° C. for 250 hours. The AC impedance spectrum confirmed that 5% MZ-CPE had good compatibility with Li metal. This indicates that the interfacial compatibility between 5% MZ-CPE and Li metal is excellent. The M-SSZ-13 nanoparticles in the electrolyte membrane have a large surface area due to their abundant nanopores, and thus can trap molecular gases and solvents. This is what limits the formation of Li metal byproducts and impurities. In addition, nanopores are uniformly distributed by M-SSZ to form a layer, and this layer prevents the cell from being short-circuited. On the other hand, the case of SPE showed an unstable interface with a short circuit after 100 hours, which is caused by the formation and continuous expansion of Li dendrites.

[Evaluation Example 5: XPS analysis]

The interaction between Li ions and zeolite was investigated using XPS analysis. 8 shows high-resolution XPS F 1s spectra of SPE and 5% MZ-CPE. For SPE, peaks were observed at 684.9 eV and 688.7 eV for the LiF and [Li(TFSI) ₂ ] ^-clusters , respectively. In the SPE sample, the peak corresponding to the [Li(TFSI) ₂ ] ^- cluster was very strong, whereas in the case of 5% MZ-CPE, the intensity of the corresponding peak was low. This confirms that dissociation of ion clusters increases by using M-SSZ-13.

[Evaluation Example 6: cyclic voltammogram]

Figure 9 shows the cyclic voltammograms of 5% MZ-CPE measured at scan rates of 5 mV/s and 10 mV/s at 60°C using a [SS/5% MZ-CPE/Li] coin cell. . Two oxidation peaks and two reduction peaks could be observed in the potential window of 6.0 V (-0.5 to 5.5 V).

[Evaluation Example 7: Rate capability]

10 shows the rate capability of [Li/5% MZ-CPE/LFP] cells at various rates from 0.1 C to 1 C at 60°C. Li metal cells using 5% MZ-CPE exhibited high initial capacities of 154, 149, 131, and 65 mAh/g at 0.1C, 0.2C, 0.5C, and 1C, respectively. Changing the rate back to 0.2 C brought the specific capacity back to 146 mAh/g, indicating the excellent stability of the [Li/5% MZ-CPE/LFP] cell.

[Evaluation Example 8: Charge / Discharge Performance]

The charge/discharge performance of the [Li/5% MZ-CPE/LFP] cell at 0.1 C was measured and shown in FIG. 11 . The initial discharge specific capacity of 5% MZ-CPE was 154 mAh/g, whereas the value of SPE was 143 mAh/g. This result confirms the high conductivity of 5% MZ-CPE and the low interfacial contact resistance between LFP and 5% MZ-CPE. Stable plateaus of Li/LFP cells using 5% MZ-CPE were observed even after 20 cycles, at which time the capacity degradation was negligible and the polarization was small (0.078 V).

[Evaluation Example 9: Cycling Performance]

The cycling performance of the [Li/5% MZ-CPE/LFP] cell at 0.1 C is shown in FIG. 12 . The discharge capacity was maintained at 144 mAh/g even after 80 cycles, and a high coulombic efficiency of 99.3% was exhibited during the entire cycling. In contrast, Li/LFP cells using 5% CPE or SPE had poorer cycle stability than 5% MZ-CPE. The 5% MZ-CPE cell had high specific capacity and high cycling stability, which means that the modification of the SSZ-13 surface resulted in faster Li ion migration and reduced interfacial reaction between electrolyte and electrode. In addition, Li/LFP using 5% MZ-CPE showed a high capacity retention rate of 97.2%, which was much higher than Li/LFP using 5% CPE and SPE (92.7% and 91.2%, respectively).

[Evaluation Example 10: Use of NCA electrode]

To investigate compatibility with other solid-state batteries, the discharge capacity of NCA using 5% MZ-CPE was measured. [Li / 5% MZ-CPE / NCA] of the coin cell structure was analyzed at a potential window of 3.0 - 4.3 V, a discharge current density of 0.1 C, and 60 °C. NCA had a first discharge capacity of 194 mAh/g and a retention capacity of 96.4% after 30 cycles. Accordingly, it can be seen that the electrolyte of the present invention can be used in other batteries in addition to the batteries used in the above-described evaluation examples.

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention described in the claims below. You will understand that you can.

Claims (16)

polymer; an inorganic additive whose surface is modified with an acrylic polymer containing a polysiloxane side chain; and a lithium salt;
The solid electrolyte composition, characterized in that the acrylic polymer containing the polysiloxane side chain is represented by the following formula (1) or formula (2).
[Formula 1]

[Formula 2]

In Formula 1 and Formula 2,
Each R may be the same as or different from each other, a straight chain alkyl group having 1 to 8 carbon atoms, and
R ¹ is a straight or branched chain alkenyl group having 2 to 8 carbon atoms;
R ² is a hydrogen atom or a group -COOR', wherein R' is a hydrogen atom or a saturated or unsaturated straight-chain, branched-chain or cyclic aliphatic alkyl group having 1 to 22 carbon atoms;
R ³ is -COOR' when c is 1, and -(CH ₂ )-COOR' or a methyl group when c is 0, where R' is as defined above;
At least a part of R ² and at least a part of R ³ have terminal groups functionalized with a hydroxyl group (—OH group),
a is a numerical value from 0 to 10,
c is 0 or 1;
m is a numerical value selected so that the weight average molecular weight of the polysiloxane side chain is in the range of 1,000 to 30,000,
m+n is a numerical value selected so that the weight average molecular weight of the acrylic polymer containing the polysiloxane side chain is in the range of 2,000 to 200,000. delete According to claim 1,
The solid electrolyte composition, characterized in that the acrylic polymer exhibits a hydroxyl value in the range of 5 to 100 mg KOH / g. According to claim 1,
The solid electrolyte composition, characterized in that the fraction of the polysiloxane side chain in the acrylic polymer is 5 to 25% by weight. According to claim 1,
The inorganic additive is a solid electrolyte composition, characterized in that zeolite. According to claim 5,
The solid electrolyte composition, characterized in that the zeolite has a CHA framework structure, and a Si / Al ratio of 5 or more. According to claim 6,
The chemical formula of the unit cell constituting the zeolite is Q _x Na _y Al _2.4 Si _33.6 O ₇₂ z H ₂ O (1.4 < x < 27) (0.7 < y < 4.3) (1 < z < 7) (Wherein, Q is N , N , N -1-trimethyladamantammonium). According to claim 6,
The zeolite is a solid electrolyte composition, characterized in that SSZ-13. According to claim 1,
The solid electrolyte composition, characterized in that the inorganic additive is included in an amount of 20% by weight or less based on the total weight of the composition. According to claim 1,
The solid electrolyte composition, characterized in that the polymer is an ion conductive polymer. According to claim 10,
The ion conductive polymer is a solid electrolyte composition, characterized in that the polyether-based polymer. According to claim 1,
The lithium salt is LiPF ₆ , LiBF ₄ , lithium bis(fluorosulfonyl)imide (Li[(FSO ₂ ) ₂ N], Li[FSI]), lithium bis(trifluoromethanesulfonyl)imide ( Li[(CF ₃ SO ₂ ) ₂ N], Li[TFSI]), lithium bisoxalate borate (Li[(O ₂ C ₂ O ₂ ) ₂ B], Li[BOB]), LiClO ₄ , LiBF ₃ ( CF ₃ ), LiBF ₃ (C ₂ F ₅ ), LiBF ₃ (C ₃ F ₇ ), LiBF ₃ (C ₄ F ₉ ), LiC(SO ₂ CF ₃ ) ₃ , CF ₃ SO ₂ OLi, CF ₃ COOLi, and R"COOLi (R" is an alkyl group having 1 to 4 carbon atoms, a phenyl group or a naphthyl group). A method for producing the solid electrolyte composition according to claim 1, comprising the step of (a) preparing a surface-modified inorganic additive by mixing an acrylic polymer having a polysiloxane side chain with an inorganic additive. According to claim 13,
(b) mixing the surface-modified inorganic additive and a lithium salt; and
(c) The manufacturing method characterized in that it further comprises the step of adding and mixing a polymer to the mixture obtained in step (b). anode;
a cathode facing the anode; and
A battery comprising an electrolyte layer comprising the solid electrolyte composition according to claim 1 between the positive electrode and the negative electrode. According to claim 15,
The battery, characterized in that the battery is a lithium ion battery, a lithium sulfur battery, or a lithium air battery.

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