KR20130000662A - Ceramic particle, polymer film and lithium battery comprising the particle, and preparing method thereof - Google Patents

Abstract

PURPOSE: A ceramic particle capable of improving charging and discharging characters of a lithium battery including a polymer film, the polymer film including the particle, and a manufacturing method of the ceramic particle are provided to enhance the amount of an impregnated electrolyte and ion conductivity of the polymer film. CONSTITUTION: A ceramic particle has a core and shell structure. The core includes silica, and the shell includes a polyelectrolyte which is chemically bonded to the core. The silica is an organic-inorganic hybrid silica. The polyelectrolyte includes a lithium ion. The chemical bond is a Si-C bond. The polymer film includes ceramic particles. The content of the ceramic particle is 3-30 parts by weight based on 100 parts by weight of the polymer. A manufacturing method of the ceramic particle comprises the following steps: preparing silica particles in which a reactive functional group is connected to the surface; and forming a polymer electrolyte layer on the silica surface by reacting the silica particles with monomers.

Description

Ceramic particles, polymer film and lithium battery comprising the same, and a method for producing the ceramic particles {Ceramic particle, polymer film and lithium battery comprising the particle, and preparing method

Ceramic particles, a polymer film and a lithium battery comprising the same, and a method for producing the ceramic particles.

Recently, with the miniaturization and high performance of electronic devices, demand for lithium batteries, which are electronic components of portable electronic devices, is increasing. The lithium battery includes a polymer film such as a separator.

Due to the miniaturization and high performance of the lithium battery, high performance of polymer films such as the separator is required. In order to improve the performance of the polymer membrane, an inorganic filler such as alumina may be added. For example, an inorganic filler was added to suppress crystallization of the polymer membrane and to improve ion conductivity.

However, despite the addition of the inorganic filler, the electrolyte solution impregnation amount and the ionic conductivity of the polymer membrane were still poor.

Therefore, there is still a need for a method of improving the electrolyte solution impregnation amount and ion conductivity of the polymer membrane.

One aspect is to provide ceramic particles of a new structure.

Another aspect is to provide a polymer film comprising the ceramic particles.

Another aspect is to provide a lithium battery comprising the polymer film.

Another aspect is to provide a method for producing the ceramic particles.

According to one side

Has a core / shell structure,

The core comprises silica,

Ceramic particles are provided wherein the shell comprises a polyelectrolyte chemically bonded to the core.

According to another aspect,

A polymer film comprising the ceramic particles is provided.

According to another aspect,

A lithium battery including the polymer film is provided.

According to another aspect,

Preparing a silica particle having a reactive functional group connected to a surface thereof; And

There is provided a method for producing ceramic particles comprising reacting the silica particles with a monomer to form a polymer electrolyte layer on the surface of silica.

According to an aspect of the present invention, the electrolyte solution impregnation amount and the ionic conductivity of the polymer film including the ceramic particles may be improved by connecting the polymer electrolyte to the silica core through the Si-C bond in the ceramic particles having the core / shell structure. The charge and discharge characteristics of the lithium battery may be improved.

1A is an SEM image of the silica core used in Example 1. FIG.
1B is an SEM image of the ceramic particles prepared in Example 1. FIG.
2A is a TEM image of the silica core used in Example 1. FIG.
Figure 2b is a TEM image of the ceramic particles prepared in Example 1.
3 is an SEM image of the polymer film prepared in Example 5.
4 is an XPS measurement result of the ceramic particles prepared in Example 1.
5 is a schematic diagram of a lithium battery according to an exemplary embodiment.
Description of the Related Art
1. Lithium battery 2. Anode
3. Anode 4. Separator
5. Battery Case 6. Assembly

Hereinafter, the ceramic particles according to the exemplary embodiments, a polymer film and a lithium battery including the same, and a method of manufacturing the ceramic particles will be described in more detail.

The ceramic particle according to the embodiment has a core / shell structure, the core includes silica, and the shell includes a polyelectrolyte chemically bonded to the core. In the polymer membrane including the ceramic particles, electrolyte content and ion conductivity may be improved.

Non-limiting reasons for improving the ion conductivity will be described below, but the description is for the purpose of understanding the present invention and does not limit the scope of the present invention.

For example, when the polymer electrolyte is chemically bonded to the core in the ceramic particles, the interface resistance between the silica core and the polymer electrolyte may be significantly reduced, thereby facilitating the transfer of ions. In addition, since lithium ions may also be present on the core surface, transfer of ions by hopping ions via the core surface may be facilitated.

In the ceramic particles, the silica may be an organic-inorganic hybrid silica. That is, an organic substituent may be included in the silica core. For example, the organic-inorganic hybrid silica may have a structure in which an organic substituent is connected to the silica skeleton.

For example, the silica may include a polysiloxane repeating unit represented by Formula 1 below:

≪ Formula 1 >

In the above formula, R ₁ is an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a thioalkyl group having 1 to 20 carbon atoms, an aminoalkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, or 2 to 20 carbon atoms. An alkynyl group of; n is an integer of 1 or more.

That is, the silica is obtained by the hydrolysis and condensation reaction of the silane compound containing a reactive functional group, it may comprise a repeating unit as shown in the formula (1).

The silica may be spherical particles. An average particle diameter of the spherical particles may be 0.1 to 1000㎛. For example, the average particle diameter of the spherical particles may be 0.5 to 10㎛. For example, the average particle diameter of the spherical particles may be 0.5 to 5㎛.

The polyelectrolyte contained in the shell may include at least one of cationic polyelectrolyte, anionic polyelectrolyte, nonionic polyelectrolyte and amphoteric polyelectrolyte.

Specifically, the anionic polyelectrolyte is polyphosphonic acid (poly (phosphoric acid)), polyvinylsulfuric acid (poly (vinylsulfuric acid)), polyvinylsulfonic acid (poly (vinylsulfonic acid)), polyvinylphosphonic acid (poly ( vinylphosphonic acid), poly (acrylic acid, PAA), poly (methacrylic acid), poly (itaconic acid), poly-4-styrenesulfonic acid (poly (4 -styrenesulfonic acid, PSS), poly (vinylphosphonic acid), polyvinylsulfonic acid, poly (glutamic acid), polyaspartic acid ), Poly (anetholesulfonic acid), poly-3-sulfopropyl methacrylate (poly (3-sulfopropyl methacrylate)), poly-1,4-phenylene ether-sulfone-sulfonic acid (poly (1 , 4-phenylene ether-sulfone-sulfonic acids), poly (1,4-phenylene ether ether ketone sulfonic acids), their Potassium salt, and it may be at least one selected from the group consisting of a copolymer thereof.

The cationic polyelectrolyte may include a polyamine including polyallylamine, polyvinylamine, and the like; Quaternized poly (acrylamides), polydiallyldimethylammonium chloride (poly (diallyldimethylammonium chloride, PDADMA-Cl), polyvinylbenzyl-trimethylammonium chloride (polyvinylbenzyl-trimethylammonium chloride, PVBTMA-Cl), Polymethacryloxyethyl-trimethylammonium bromide (poly (methacryloxyethyltrimethylammonium bromide), polymethacryloyloxyethyltrimethylammonium methyl sulfate (poly (methacryloyloxyethyltrimethylammonium methyl sulfate), polyhydroxypropylmethacryloxyethyldimethylammonium chloride (poly (hydroxypropylmethacryloxyethyldimethylammonium chloride), poly-N-acrylamidopropyl-3-trimethylammonium chloride (poly (N-acrylamidopropyl-3-trimethylammonium chloride), polyacrylamide / methacryloxypropyltrimethylammonium bromide (poly (acrylamide / methacryloxypropyltrimethylammonium bromide ), Polybrene®, Paul Poly (ethylenimine-epichlorohydrin ammonium chloride), poly-2-dimethylamino-ethyl methacrylate methylchloride quaternary salt (poly (2-dimethylamino-ethyl methacrylate methylchloride quaternary salt)), Poly (ammonium salts) including natural polymers having quaternized substituents including nitrogen; poly (imines) including poly (ethylenimine), PEI, and the like ); Poly (dimethylaminoethyl-acrylamide), polydimethylaminopropyl acrylamide, polymethyldiethylaminoethyl acrylamide, polydi Poly (acrylamides) including allyldimethyl-ammonium chloride / N-isopropylacrylamide (poly (diallyldimethyl-ammonium chloride / N-isopropylacrylamide)) )); Poly (acrylates) including polydimethylaminoethyl acrylate (poly (dimethylaminoethyl acrylate)), poly-t-butylaminoethyl acrylate (poly (t-butylaminoethyl acrylate)) and the like; Polydimethylaminoethyl methacrylate (poly (dimethylaminoethyl methacrylate)), poly-t-butylaminoethyl methacrylate (poly (t-butylaminoethyl methacrylate)), polymethyldiethylaminoethyl methacrylate (poly (methyldiethylaminoethyl methacrylate) Poly (methacrylates), including; Poly (imidazoline), polyvinylpyridine, polyvinylpyrrolidones, polyvinyllimidazoline (PVI), polymethylvinyl Poly (cyclicamines) including pyridinium chloride (poly (methylvinylpyridinium bromide), poly (methylvinylpyridinium chloride)) and the like; Poly (sulfonium salts) including polyacryloxyethyldimethylsulfonium chloride (poly) and the like, poly (glycidyltributylphosphonium chloride) and the like poly (glycidyltributylphosphonium chloride) Phosphonium salts (poly (phosphonium salts)); polyaniline; polyethyleneamine; polypyridinium; and copolymers thereof.

The amphoteric polymer electrolyte is poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (Poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate), PEDOT: PSS), poly (2-acrylamide Fig. 2-Methyl-1-propanesulfonic acid) (poly (2-acrylamido-2-methyl-1-propanesulfonic acid), polysulfobetaine, polycarbobetaine, acrylic acid-dimethylaminoethyl methacrylate copolymer and maleic acid It may comprise one or more selected from the group consisting of diallylamine copolymer.

The nonionic polymer electrolyte is composed of polyethylene oxide, polypropylene oxide, polyethylene glycol-polypropylene glycol copolymer, polyethylene glycol-polypropylene glycol-polyethylene glycol block copolymer, and polypropylene glycol-polyethylene glycol-polypropylene glycol block copolymer It may include one or more selected from the group.

For example, the polyelectrolyte may include one or more repeating units selected from the group consisting of Formulas 2 and 3:

<Formula 2> <Formula 3>

In the above formulas, n is 2 to 10000, A is a covalent bond, an arylene group having 6 to 20 carbon atoms or an alkylene group having 1 to 20 carbon atoms, and X is an alkali metal. For example, A may be a covalent bond, a phenylene group, a methylene group, or the like. The alkali metal may be, for example, lithium, sodium, potassium.

The polymer electrolyte may include lithium ions. By including the lithium ions, the ion conductivity of lithium ions in the polymer membrane including the polymer electrolyte may be improved. The polymer film may be used as a separator of a lithium battery.

The chemical bond connecting the polymer electrolyte and the core in the ceramic particles is a Si-C bond. That is, Si is bonded to silica and C of polyelectrolyte. Si exposed on the silica surface forms a bond with C of the polymer electrolyte to form an organic-inorganic hybrid composite ceramic.

The polymer film according to another embodiment includes the ceramic particles. The polymer membrane may include an electrolyte impregnation amount and an ionic conductivity by including ceramic particles having the core / shell structure.

For example, the polymer membrane may be a polyelelctrolyte membrane or a non-polyelectrolyte memebrane. The non-polymer electrolyte membrane refers to a membrane including a polymer which contains pores in the polymer but does not include an ionic functional group and thus cannot function as an electrolyte. For example, it may include polyethylene, polypropylene, and the like. The polymer film may be used as a separator.

The polymer electrolyte membrane may include at least one of a cationic polymer electrolyte, an anionic polymer electrolyte, a nonionic polymer electrolyte and an amphoteric polymer electrolyte. The cationic polyelectrolyte, anionic polyelectrolyte, nonionic polyelectrolyte and / or amphoteric polyelectrolyte may be the same as those included in the shell of the ceramic particles.

The non-polymer electrolyte membrane is polyester, polyethylene, polypropylene, polytetrafluoroethylene (PTFE) vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile and polymethyl methacrylate. It may include one or more selected from the group consisting of, but are not necessarily limited to these, any one that can be used as a separator in the art.

The content of the ceramic particles in the polymer film may be 3 to 30 parts by weight with respect to 100 parts by weight of the polymer, but is not necessarily limited to this range and may be used outside the range if the object of the present invention can be achieved.

The polymer film may have a thickness of 10 to 80 μm, but is not necessarily limited to this range, and may be used outside the range as long as the object of the present invention can be achieved. For example, the thickness of the polymer film may be 20 to 60㎛.

The polymer film used as a separator of a lithium battery can be manufactured as follows, for example.

After the ceramic particles, the polymer resin, the filler and the solvent are mixed to prepare a separator composition, the separator composition is directly coated and dried on an electrode to form a separator film, or the separator composition is cast and dried on a support. The separator film peeled from the support may be formed by being laminated on the electrode.

The polymer resin is not particularly limited, and any polymer can be used as long as it is a material used as a binder of the electrode plate. For example, polyethylene, polypropylene, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate or mixtures thereof may be used in the lithium ion battery. It is suitable to use vinylidene fluoride / hexafluoropropylene copolymers having a hexafluoropropylene content of 8 to 25% by weight.

Lithium battery according to another embodiment may include the polymer film. For example, the lithium battery may include charge and discharge characteristics, such as an improved initial discharge capacity and capacity retention rate, by including the polymer film.

The lithium battery is a cathode (cathode); An anode; A polymer membrane separator and electrolyte are included. The lithium battery may be manufactured, for example, as follows.

First, a positive electrode plate is prepared.

A cathode active material, a conductive agent, a binder, and a solvent are mixed to prepare a cathode active material composition. The positive electrode active material composition is directly coated and dried on an aluminum current collector to prepare a positive electrode plate, or the positive electrode active material composition is cast on a separate support, and then a film obtained by peeling from the support is laminated on the aluminum current collector. Thus, the positive electrode plate can be manufactured. Alternatively, the cathode active material composition may be prepared in the form of an electrode ink including an excess of solvent and printed on the support by an inkjet method or a gravure printing method to prepare a cathode electrode plate. The printing method is not limited to the above method, and any method that can be used for general coating and printing can be used.

The cathode active material used for the cathode is a lithium-containing metal oxide, and any one may be used without limitation as long as it is commonly used in the art. For example, one or more of a complex oxide of metal and lithium selected from cobalt, manganese, nickel, and combinations thereof may be used, and specific examples thereof include Li _a A _1-b B _b D ₂ (the Wherein 0.90 ≦ a ≦ 1.8, and 0 ≦ b ≦ 0.5); Li _a E _1-b B _b O _{2 -c} D _c wherein, in the formula, 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05; LiE _2-b B _b 0 _4-c D _c (wherein 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.05); Li _a Ni _{1 -bc} Co _b B _c D _? Wherein, in the formula, 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _{1- b c} Co _b B _c O _{2 -?} F _? Wherein? 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _{1- b c} Co _b B _c O _2-α F ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α <2; Li _a Ni _1-bc Mn _b B _c D _? Wherein, in the formula, 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _1-bc Mn _b B _c O _2-α F _α wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α <2; Li _a Ni _1-bc Mn _b B _c O _2-α F ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α <2; Li _a Ni _b E _c G _d O ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, and 0.001 ≤ d ≤ 0.1; Li _a Ni _b Co _c Mn _d GeO ₂ wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, and 0.001 ≤ e ≤ 0.1; Li _a NiG _b O ₂ (in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1); Li _a CoG _b O ₂ wherein, in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1; Li _a MnG _b O ₂ (in the above formula, 0.90? A? 1.8, 0.001? B? 0.1); Li _a Mn ₂ G _b O ₄ wherein, in the above formula, 0.90? A? 1.8, and 0.001? B? 0.1; QO _2; QS ₂ ; LiQS ₂ ; V ₂ O ₅ ; LiV ₂ O ₅ ; LiIO ₂ ; LiNiVO _4; Li _(3-f) J ₂ (PO ₄ ) ₃ (0? F? 2); Li _(3-f) Fe ₂ (PO ₄ ) ₃ (0? F? 2); In the formula of LiFePO ₄ may be used a compound represented by any one:

In the above formula, A is Ni, Co, Mn, or a combination thereof; B is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

For example, LiCoO ₂ , LiMn _x O _2x (x = 1, 2), LiNi _1-x Mn _x O _2x (0 <x <1), Ni _1-xy Co _x Mn _y O ₂ (0 ≦ _x ≦ 0.5, 0 ≦ y ≦ 0.5), LiFePO _4, and the like.

Of course, it is also possible to use a coating layer on the surface of the compound, or may be used by mixing the compound having a compound with the coating layer. The coating layer may comprise an oxide, a hydroxide of the coating element, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, or a coating element compound of the hydroxycarbonate of the coating element. The compound constituting these coating layers may be amorphous or crystalline. The coating layer may contain Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr or a mixture thereof. The coating layer forming step may be any coating method as long as it can coat the above compound by a method that does not adversely affect physical properties of the cathode active material (for example, spray coating, dipping, etc.) by using these elements, It will be understood by those skilled in the art that a detailed description will be omitted.

Carbon black may be used as the conductive agent, and vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene, Mixtures or polyimides, polyamide imides, styrene butadiene rubber-based polymers, acrylate rubbers, sodium carboxymethylcellulose, and the like can be used, and N-methylpyrrolidone, acetone, water and the like can be used as the solvent.

The amount of the positive electrode active material, the conductive agent, the binder, and the solvent is at a level commonly used in lithium batteries.

Next, a negative electrode plate is prepared.

As in the case of the positive electrode plate described above, a negative electrode active material, a conductive agent, a binder and a solvent are mixed to prepare a negative electrode active material composition. The negative electrode active material composition is directly coated and dried on a copper current collector to prepare a negative electrode plate, or the negative electrode active material film cast on a separate support and peeled from the support is laminated to a copper current collector to obtain a negative electrode plate. Alternatively, the negative electrode active material composition may be prepared in the form of an electrode ink including an excess of solvent and printed on the support by an inkjet method or a gravure printing method to prepare a negative electrode plate. The printing method is not limited to the above method, and any method that can be used for general coating and printing can be used.

As a negative electrode active material used for the said anode, Graphite type materials, such as a graphite particle; Metal alloyable with lithium such as silicon fine particles; Graphite / silicon composites; Transition metal oxides such as lithium titanium oxide (Li ₄ Ti ₅ O ₁₂ ); And the like may be used, but the present invention is not limited thereto, and any one used in the art may be used. For example, graphite particles are natural graphite, artificial graphite, or the like. The size of the graphite particles is preferably 5 to 30 µm. The size of the silicon fine particles is preferably 50nm to 10㎛, but is not necessarily limited to this range. The graphite particles and silicon fine particles may be compounded by a general method used in the art such as mechanical milling to form a graphite / silicon composite.

The conductive agent, the binder and the solvent may be the same as those used for the production of the positive electrode plate. The amount of the negative electrode active material, the conductive agent, the binder, and the solvent is at a level commonly used in lithium batteries.

A plasticizer may be added to the cathode active material composition and the anode active material composition to form pores in the electrode plate.

Next, the separator which is a polymer film containing the above-mentioned ceramic particle is prepared. The separator is low in resistance to ion migration of the electrolyte and has excellent ability to hydrate the electrolyte. The positive electrode and the negative electrode may be separated by a separator, and any polymer used in the separator may be used as long as it is commonly used in lithium batteries. For example, the polymer may be a material selected from polyester, teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), or a combination thereof, and may be nonwoven or woven. More specifically, in the lithium ion battery, a wound polymer such as polyethylene and polypropylene may be used, and in the lithium ion polymer battery, a polymer having excellent organic electrolyte impregnation ability may be used.

Next, the electrolyte is prepared.

For example, an organic electrolytic solution can be prepared. The organic electrolytic solution can be prepared by dissolving a lithium salt in an organic solvent.

The organic solvent may be any organic solvent which can be used in the art. For example, propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate , Benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, dioxolane, 4-methyldioxolane, N, N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide , Dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether or a mixture thereof.

The lithium salt may also be used as long as it can be used in the art as a lithium salt. For example, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , LiAlO ₂ , LiAlCl ₄ , LiN (C _x F _{2x + 1} SO ₂ ) (C _y F _{2y + 1} SO ₂ ) (where x and y are natural numbers), LiCl, LiI or a mixture thereof.

As shown in FIG. 5, the lithium battery 1 includes a positive electrode 3, a negative electrode 2, and a separator 4. The anode 3, the cathode 2 and the separator 4 described above are wound or folded and housed in the battery case 5. Then, an organic electrolytic solution is injected into the battery case 5 and is sealed with a cap assembly 6 to complete the lithium battery 1. The battery case may have a cylindrical shape, a rectangular shape, a thin film shape, or the like. For example, the lithium battery may be a large thin film type battery. The lithium battery may be a lithium ion battery.

A separator may be disposed between the positive electrode and the negative electrode to form a battery structure. The battery structure is stacked in a bi-cell structure, and then impregnated in an organic electrolyte, and the resultant is accommodated in a pouch and sealed to complete a lithium ion polymer battery.

In addition, a plurality of battery assemblies may be stacked to form a battery pack, and such battery pack may be used for all devices requiring high capacity and high output. For example, it can be used in notebooks, smartphones, electric vehicles and the like.

In addition, the lithium battery may be used in an electric vehicle (EV) because of its excellent storage stability, lifetime characteristics, and high rate characteristics at high temperatures. For example, it may be used in a hybrid vehicle such as a plug-in hybrid electric vehicle (PHEV).

According to another embodiment, a method of preparing ceramic particles includes preparing silica particles having a reactive functional group connected to a surface thereof; And forming a polymer electrolyte layer on the silica surface by reacting the silica particles with the monomer.

Silica particles having a reactive functional group linked to the surface may be prepared by hydrolyzing and condensing a silane compound represented by Formula 6 below:

(6)

SiR ⁴ _m (OR ⁴ ) _4-m

In the above formula, R ⁴ is an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a thioalkyl group having 1 to 20 carbon atoms, an aminoalkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, or 2 to 20 carbon atoms. 20 is alkynyl group; m is an integer of 0-3, k is an integer of 1-3.

Thus, the silica particles may include reactive functional groups (R ⁴ ) in the particles and on the surface of the particles. The reactive functional group is an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a thioalkyl group having 1 to 20 carbon atoms, an aminoalkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms and alkynyl having 2 to 20 carbon atoms. It may be one or more selected from the group consisting of groups. For example, the reactive functional group may be a vinyl group.

The monomer is a monomer containing at least one of a cationic functional group, a nonionic functional group, an anionic functional group and an amphoteric functional group, and is a monomer used in the preparation of a polymer electrolyte, and the monomer is reacted with a reactive functional group on the surface of the silica particles. A chemical bond may be formed between the core and the polymer electrolyte. The chemical bond may be a Si—C bond, for example.

For example, the monomer may be one or more selected from the group consisting of Formulas 4 to 5.

<Formula 4> <Formula 5>

In the above formulas, A is a covalent bond, an arylene group having 6 to 20 carbon atoms or an alkylene group having 1 to 20 carbon atoms, and X is an alkali metal.

The technical spirit will be described in more detail with reference to the following examples and comparative examples. However, the embodiments are provided to illustrate the technical idea and the scope of the technical idea is not limited thereto.

(Manufacture of Ceramic Particles)

Example 1

10 g of vinyltrimethylmethoxysilane (Sigma-Aldrich Co.) was added to 100 g of water, and vigorously stirred for 2 hours to completely dissolve. The mixture was then adjusted to pH 11 by addition of NH ₄ OH (0.1 ml) at room temperature. Reaction was carried out for 12 hours to obtain a precipitate. The precipitate was separated and washed with alcohol to obtain a silica core having a vinyl group connected to the surface. The average particle diameter of the obtained silica core was 0.9 micrometer. An SEM image of the silica core is shown in FIG. 1A. 2A shows a TEM image of the silica core.

1.5 g of the silica particles and 1.5 g of sodium salt of 4-styrenesulfonic acid were added to 150 g of an NMP (N-methylpyrrolidone) solvent, and 2,2'-azobis (2-ethylpropionamidine) as a radical catalyst was added thereto. 0.4g was added and solution polymerization was performed. As a result of the polymerization, core / shell particles having a shell, which is a poly (sodium 4-styrenesulfonate) polyelectrolyte, were formed on the silica core. 6 g of core / shell particles were added to a solution in which lithium hydrate was dissolved in 100 ml of NMP, and reacted under nitrogen atmosphere at 60 ° C. for 12 hours to replace the sodium with lithium in the particles having the core / shell structure. This substituted ceramic particle was obtained.

The average particle diameter of the said ceramic particle was 1.4 micrometers. 1b shows an SEM image of the ceramic particles. 2B shows a TEM image of ceramic particles having the core / shell structure.

(Production of Polymer Film)

Example 2

5 parts by weight of the ceramic particles prepared in Example 1 and 105 parts by weight of dibutyl phthalate were added to 100 parts by weight of Kynar 2801 ㄾ (PVdF-HFP copolymer) to 700 parts by weight of acetone solvent, followed by stirring at room temperature for 12 hours. Was prepared. The polymer solution was cast on a glass substrate and then dried.

The glass substrate on which the polymer membrane was cast was immersed in methanol for 12 hours to remove dibutylphthallay, thereby preparing a polymer membrane including ceramic particles.

The thickness of the polymer film was 40 μm.

Example 3

A polymer film was prepared in the same manner as in Example 2, except that the content of the ceramic particles prepared in Example 1 was changed to 10 parts by weight.

Example 4

A polymer film was manufactured in the same manner as in Example 2, except that the content of the ceramic particles prepared in Example 1 was changed to 15 parts by weight.

Example 5

A polymer film was manufactured in the same manner as in Example 2, except that the content of the ceramic particles prepared in Example 1 was changed to 20 parts by weight. The polymer membrane is a porous membrane as in the SEM image shown in FIG. 3.

Example 6

A polymer film was manufactured in the same manner as in Example 2, except that the content of the ceramic particles prepared in Example 1 was changed to 25 parts by weight.

Example 7

A polymer film was prepared in the same manner as in Example 5, except that the thickness of the polymer film was changed to 10 μm.

Example 8

A polymer membrane was manufactured in the same manner as in Example 5, except that the thickness of the polymer membrane was changed to 20 μm.

Example 9

A polymer membrane was manufactured in the same manner as in Example 5, except that the thickness of the polymer membrane was changed to 30 μm.

Example 10

A polymer membrane was prepared in the same manner as in Example 5, except that the thickness of the polymer membrane was changed to 50 μm.

Example 11

A polymer membrane was manufactured in the same manner as in Example 5, except that the thickness of the polymer membrane was changed to 60 μm.

Example 12

A polymer film was prepared in the same manner as in Example 5, except that the thickness of the polymer film was changed to 70 μm.

Example 13

A polymer film was prepared in the same manner as in Example 5, except that the thickness of the polymer film was changed to 80 μm.

Comparative Example 1

Instead of the polymer membrane, Cellgard 2400 ㄾ (PP) membrane was used.

Comparative Example 2

100 parts by weight of dibutyl phthalate was added to 700 parts by weight of acetone solvent and 100 parts by weight of Kynar 2801 ㄾ, and stirred at room temperature for 12 hours to prepare a polymer solution. The polymer solution was cast on a glass substrate and then dried.

The glass substrate on which the polymer membrane was cast was immersed in methanol for 12 hours to remove dibutylphthallay to prepare a polymer membrane.

The thickness of the polymer film was 40 μm.

Comparative Example 3

20 parts by weight of fumed silica (Degussa) and 120 parts by weight of dibutyl phthalate were added to 700 parts by weight of acetone solvent and 100 parts by weight of Kynar 2801 ㄾ to prepare a polymer solution by stirring at room temperature for 12 hours. The polymer solution was cast on a glass substrate and then dried.

The glass substrate on which the polymer membrane was cast was immersed in methanol for 12 hours to remove dibutylphthallay, thereby preparing a polymer membrane including fumed silica particles.

The thickness of the polymer film was 40 μm.

(Production of lithium battery)

Example 14

85 parts by weight of artificial graphite (MCMB) particles having an average particle diameter of 20 μm, 7.5 parts by weight of graphite-based conductive agent (super-P, Timcal Inc.), and 5% by weight of N-methylpyrrolidone A slurry was prepared by mixing 150 parts by weight of a solution in which polyvinylidene fluoride (PVdF) was dissolved in agate mortar. The slurry was applied to a copper collector having a thickness of 15 μm using a doctor blade to a thickness of about 60 μm, dried for 2 hours in a hot air dryer at 100 ° C., and then dried again under vacuum and 120 ° C. for 2 hours. Prepared.

LiCoO ₂ powder, carbon conductive material (KS-6, Lonza), carbon conductive material (Super-P, Timcal) and polyvinylidene fluoride (PVDF) binders with an average particle diameter of 20 µm were uniformly mixed at a weight ratio of 85: 3.25: 3.25: 7.5 After the mixing, the solution was added to prepare a slurry such that the weight ratio of the active material: carbon conductive agent: binder = 85: 7.5: 7.5.

The active material slurry was applied to a thickness of about 60 μm on a 15 μm thick aluminum foil, and dried for 2 hours in a hot air dryer at 100 ° C., and then dried again for 2 hours under vacuum and 120 ° C. to prepare a positive electrode plate.

The positive electrode plate and the negative electrode plate were used as the positive electrode and the negative electrode, and the polymer membrane prepared in Example 5 was used as the separator as the separator, and 1.0 M LiPF ₆ is EC (ethylene carbonate) + DEC (diethylene carbonate) (3: 7 volume ratio). ) Was used as an electrolyte to prepare a coin cell of the 2023 standard.

Example 15-25

A coin cell was manufactured in the same manner as in Example 14, except that the polymer film prepared in Example 3-13 was used.

Comparative Example 4-6

A coin cell was manufactured in the same manner as in Example 14, except that the polymer membrane prepared in Comparative Example 1-3 was used.

Evaluation Example 1: XPS Experiment

XPS was measured on the ceramic particles prepared in Example 1, and it was checked whether lithium ions were included in the ceramic particles. As shown in FIG. 4, a characteristic peak corresponding to lithium ions appeared.

Evaluation Example 2: Measurement of Electrolyte Impregnation and Ion Conductivity

The electrolyte solution impregnation amount and the ion conductivity of the polymer membranes prepared in Examples 2-13 and Comparative Examples 1-3 were measured, and some of the results are shown in Table 1 below.

The electrolyte solution impregnation amount was immersed in a solution in which 1.0 M LiPF ₆ was dissolved in EC (ethylene carbonate) + DEC (diethylene carbonate) (3: 7 volume ratio) for 1 hour, and then measured by the weight before and after electrolyte impregnation. The electrolyte solution impregnation amount was calculated from Equation 1.

&Quot; (1) &quot;

Electrolyte impregnation amount = [(WW ₀ ) / W ₀ ] × 100

W is the weight of the polymer film after impregnation of the electrolyte, and W ₀ is the weight of the polymer film before impregnation of the electrolyte.

The ion conductivity of the polymer membrane impregnated with the electrolyte was measured using a Solartron 1260 Impedance Analyzer. The results are shown in Table 1 below.

Electrolyte impregnation
[%] Ion conductivity
[S / cm] Example 2 146 6.9 × 10 ^-4 Example 3 154.1 8.1 × 10 ^-4 Example 4 166.6 8.9 × 10 ^-4 Example 5 176.5 13.0 × 10 ^-4 Example 6 181.2 10.0 × 10 ^-4 Example 8 108.6 6.7 × 10 ^-4 Example 9 121.6 13.0 × 10 ^-4 Example 10 136.8 8.2 × 10 ^-4 Example 11 106.9 6.4 × 10 ^-4 Example 12 86.6 6.4 × 10 ^-4 Comparative Example 1 79.5 3.3 × 10 ^-4 Comparative Example 2 125.4 3.9 × 10 ^-4 Comparative Example 3 141.3 4.5 × 10 ^-4

As shown in Table 1, the polymer membranes of Examples 2-6 and 8-12 have improved ion conductivity as compared with the polymer membranes of Comparative Examples 1-3, and the electrolyte impregnation amount is also improved overall.

Evaluation Example 3 Charge / Discharge Experiment

Charge and discharge experiments were performed on the lithium batteries prepared in Examples 14-25 and Comparative Examples 4-6, and a part of the results are shown in Table 2 below.

First, constant current charging was performed at 0.1 C until the voltage reached 4.2 V (vs. Li), followed by constant voltage charging until the current decreased to 0.05 C while applying a constant voltage of 4.2 V. Subsequently, after 10 minutes of rest, constant current discharge was performed to 3.0 V (vs. Li) at a current of 0.1C.

The charging and discharging was repeated once more to complete the chemical conversion step.

Next, the battery was charged with a constant current until the voltage reached 4.2V (vs. Li) at 0.5C, and then constant voltage charged until the current decreased to 0.05C while applying a constant voltage of 4.2V. Subsequently, after a 10 minute rest period, constant current discharge was performed to 3.0 V (vs. Li) at a current of 0.5 C (1 ^st cycle). The cycle was repeated 20 times.

Discharge capacity and capacity retention rate were measured in the first cycle and the results are shown in Table 2 below. The capacity retention rate is calculated from the following equation.

&Quot; (2) &quot;

Capacity maintenance rate at 20th cycle = 20th cycle discharge capacity / 1st cycle discharge capacity

Initial discharge capacity
[mAh / g] In the 20th cycle
Capacity maintenance rate
[%] Example 14 148.2 96.0 Example 15 148.0 97.2 Example 16 148.5 96.7 Example 17 149.2 96.9 Example 18 150.0 96.4 Example 20 141.5 95.0 Comparative Example 6 136.1 94.2

As shown in Table 2, the lithium batteries of Examples 14-18 and 20 have improved initial discharge capacity and capacity retention rate compared to the lithium batteries of Comparative Example 6.

Claims (25)

Has a core / shell structure,
The core comprises silica,
Ceramic shell comprising a polyelectrolyte chemically bonded to the core of the shell. The ceramic particle of claim 1, wherein the silica is an organic-inorganic hybrid silica. The ceramic particle of claim 1, wherein the silica comprises a polysiloxane repeating unit represented by Formula 1 below:
&Lt; Formula 1 >

In this formula,
R ₁ is an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a thioalkyl group having 1 to 20 carbon atoms, an aminoalkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, or an alkynyl group having 2 to 20 carbon atoms Is;
n is an integer of 1 or more. The ceramic particle of claim 1, wherein the silica is a spherical particle. The ceramic particle according to claim 4, wherein the spherical particles have an average particle diameter of 0.1 to 1000 mu m. 5. The ceramic particle of claim 4, wherein the polydispersity index (PDI) of the spherical particles is less than 0.5. The ceramic particle of claim 1, wherein the polyelectrolyte comprises at least one of a cationic polyelectrolyte, an anionic polyelectrolyte, a nonionic polyelectrolyte, and an amphoteric polyelectrolyte. The method of claim 7, wherein the anionic polyelectrolyte is poly (phosphoric acid), polyvinylsulfuric acid, polyvinylsulfonic acid, polyvinylphosphonic acid (poly (vinylphosphonic acid)), poly (acrylic acid, PAA), poly (methacrylic acid), poly (itaconic acid), poly-4-styrenesulfonic acid ( poly (4-styrenesulfonic acid), PSS), poly (vinylphosphonic acid), poly (vinylsulfonic acid), polyglutamic acid, polyasphalt acid aspartic acid), poly (anetholesulfonic acid), poly-3-sulfopropyl methacrylate, poly-1,4-phenylene ether-sulfone-sulfonic acid ( poly (1,4-phenylene ether-sulfone-sulfonic acids)), poly-1,4-phenylene ether ketone sulfonic acids, The alkali metal salts, and one or more ceramic particles selected from the group consisting of a copolymer thereof. 8. The method of claim 7, wherein the cationic polyelectrolyte comprises: poly (amine) including polyallylamine, polyvinylamine, etc .; Quaternized poly (acrylamides), polydiallyldimethylammonium chloride (PDADMA-Cl), polyvinylbenzyl-trimethylammonium chloride (PVBTMA-Cl) ), Polymethacryloxyethyl-trimethylammonium bromide (poly (methacryloxyethyl-trimethylammonium bromide), polymethacryloyloxyethyltrimethylammonium methyl sulfate), polyhydroxypropylmethacryloxyethyldimethylammonium chloride ( poly (hydroxypropylmethacryloxyethyldimethylammonium chloride), poly-N-acrylamidopropyl-3-trimethylammonium chloride (poly (N-acrylamidopropyl-3-trimethylammonium chloride), polyacrylamide / methacryloxypropyltrimethylammonium bromide (poly (acrylamide / methacryloxypropyltrimethylammonium bromide, polybrene, poly Poly (ethylenimine-epichlorohydrin ammonium chloride), poly-2-dimethylamino-ethyl methacrylate methylchloride quaternary salt (poly (2-dimethylamino-ethyl methacrylate methylchloride quaternary salt)), Poly (ammonium salts) including natural polymers having quaternized substituents including nitrogen; poly (imines) including poly (ethylenimine), PEI, and the like ); Poly (dimethylaminoethyl-acrylamide), polydimethylaminopropyl acrylamide, polymethyldiethylaminoethyl acrylamide, polydi Poly (acrylamides) including allyldimethyl-ammonium chloride / N-isopropylacrylamide (poly (diallyldimethyl-ammonium chloride / N-isopropylacrylamide)) )); Poly (acrylates) including polydimethylaminoethyl acrylate (poly (dimethylaminoethyl acrylate)), poly-t-butylaminoethyl acrylate (poly (t-butylaminoethyl acrylate)) and the like; Polydimethylaminoethyl methacrylate (poly (dimethylaminoethyl methacrylate)), poly-t-butylaminoethyl methacrylate (poly (t-butylaminoethyl methacrylate)), polymethyldiethylaminoethyl methacrylate (poly (methyldiethylaminoethyl methacrylate) Poly (methacrylates), including; Poly (imidazoline), polyvinylpyridine, polyvinylpyrrolidones, polyvinyllimidazoline (PVI), polymethylvinyl Poly (cyclicamines) including pyridinium chloride (poly (methylvinylpyridinium bromide), poly (methylvinylpyridinium chloride)) and the like; Poly (sulfonium salts) including polyacryloxyethyldimethylsulfonium chloride (poly) and the like, poly (glycidyltributylphosphonium chloride) and the like poly (glycidyltributylphosphonium chloride) Phosphonium salts (poly (phosphonium salts)); ceramic particles comprising at least one selected from the group consisting of polyaniline, polyethyleneamine, polypyridinium, and copolymers thereof. The method of claim 7, wherein the amphoteric polyelectrolyte is poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (Poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate), PEDOT: PSS), Poly (2-acrylamido-2-methyl-1-propanesulfonic acid) (poly (2-acrylamido-2-methyl-1-propanesulfonic acid), polysulfobetaine, polycarbobetaine, acrylic acid-dimethylaminoethyl meta Ceramic particles comprising at least one selected from the group consisting of acrylate copolymers and maleic acid-diallylamine copolymers. The method of claim 7, wherein the nonionic polymer electrolyte is polyethylene oxide, polypropylene oxide, polyethylene glycol-polypropylene glycol copolymer, polyethylene glycol-polypropylene glycol-polyethylene glycol block copolymer and polypropylene glycol-polyethylene glycol-polypropylene Ceramic particles comprising at least one selected from the group consisting of glycol block copolymers. The ceramic particle of claim 1, wherein the polymer electrolyte is at least one selected from the group consisting of Chemical Formulas 2 and 3:
<Formula 2><Formula3>

In the above equations,
n is 2 to 10000,
A is a covalent bond, an arylene group having 6 to 20 carbon atoms or an alkylene group having 1 to 20 carbon atoms,
X is an alkali metal. The ceramic particle of claim 1, wherein the polymer electrolyte comprises lithium ions. The ceramic particle of claim 1, wherein the chemical bond is a Si—C bond. The polymer film containing the ceramic particle of any one of Claims 1-14. The polymer membrane of claim 15, wherein the polymer membrane is a polyelectrolyte membrane or a non-polyelectrolyte membrane. The polymer membrane of claim 16, wherein the polymer electrolyte membrane comprises at least one of a cationic polymer electrolyte, an anionic polymer electrolyte, a nonionic polymer electrolyte, and an amphoteric polymer electrolyte. The method of claim 16 wherein the polymer membrane is polyester, polyethylene, polypropylene, polytetrafluoroethylene (PTFE) vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile and polymethyl Polymer membrane comprising one or more selected from the group consisting of methacrylate. The polymer membrane of claim 15, wherein the content of the ceramic particles is 3 to 30 parts by weight based on 100 parts by weight of the polymer. The polymer membrane of claim 15, wherein the polymer membrane has a thickness of 10 to 80 μm. A lithium battery comprising the polymer film of claim 15. Preparing a silica particle having a reactive functional group connected to a surface thereof; And
Reacting the silica particles and the monomer to form a ceramic particle comprising the step of forming a polymer electrolyte layer on the surface of the silica. 23. The method according to claim 22, wherein the reactive functional group is an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, a thioalkyl group having 1 to 20 carbon atoms, an aminoalkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms and a carbon number At least one selected from the group consisting of 2 to 20 alkynyl groups. The method of claim 22, wherein the monomer comprises at least one of a cationic functional group, a nonionic functional group, an anionic functional group and an amphoteric functional group. The method of claim 22, wherein the monomer is at least one selected from the group consisting of Formulas 4 to 5:
<Formula 4><Formula5>

In the above equations,
A is a covalent bond, an arylene group having 6 to 20 carbon atoms or an alkylene group having 1 to 20 carbon atoms,
X is an alkali metal.

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