KR20220094556A - Method for manufacturing an active material composite for secondary batteries, and an active material composite for secondary batteries manufactured thereby - Google Patents

Abstract

The present invention relates to a method for manufacturing an active material composite for a secondary battery, and an active material composite for a secondary battery that is manufactured thereby to have a core-shell structure. The active material composite for a secondary battery manufactured according to the present invention includes a shell formed by bonding a functional group having a specific chemical formula with polycyclic hydrocarbon by π-π-interaction on a core including an active material, so that the volume expansion of the active material in the active material composite can be controlled and the stability and capacitance of a secondary battery including the active material can be excellently secured.

Description

Method for manufacturing an active material composite for secondary batteries, and an active material composite for secondary batteries manufactured thereby, and an active material composite for secondary batteries manufactured thereby

The present invention relates to a method for manufacturing an active material composite for a secondary battery, and to an active material composite for a secondary battery manufactured according to the method and having a core-shell structure.

As the demand for electric vehicles and large-capacity power storage devices increases, various batteries have been developed to satisfy them.

Among them, lithium secondary batteries have been widely commercialized because of their excellent energy density and output characteristics among various secondary batteries. As a lithium secondary battery, a lithium secondary battery (hereinafter referred to as a 'liquid-type secondary battery') including a liquid-type electrolyte containing an organic solvent has been mainly used.

However, in the liquid type secondary battery, the liquid electrolyte is decomposed by the electrode reaction, causing the battery to expand, and the risk of ignition due to leakage of the liquid electrolyte has been pointed out. In order to solve the problems of the liquid type secondary battery, a lithium secondary battery to which a solid electrolyte having excellent stability is applied is attracting attention.

Meanwhile, graphite, which can store lithium ions, has been mainly used as a negative electrode material for conventional secondary batteries. However, graphite suffers from many difficulties due to its limited capacity due to its low capacity per unit mass. It is one of the challenges to be solved.

Recently, the characteristics required for a battery for a hybrid vehicle include specific energy, high rate characteristic, internal resistance, and lifespan. is in reality.

Accordingly, research on anode materials that can increase capacity than graphite has been conducted. Typically, a technology for increasing the capacity of a secondary battery by changing a carbon-based material to a silicon-based material is being studied. However, when a silicon-based material is used as a negative electrode material for a secondary battery, there is a problem in that the volume expands due to a change in the crystal structure when the lithium ion of the secondary battery is absorbed. That is, there was a disadvantage that the lifespan of the secondary battery significantly decreased as the volume of the negative electrode material expanded during charging and discharging of the secondary battery.

Korean Air Patent Publication No. 10-2017-0003555

The present invention is intended to solve the above problems, and the specific objects thereof are as follows.

In the present invention, an active material containing an oxide is prepared as a core, a functional group having a specific chemical formula is placed on the surface of the active material, and then a polycyclic hydrocarbon including 5 or more aromatic rings is added to the functional group Cyclic hydrocarbons are bonded to each other by π-π-interaction, thereby forming a shell on the surface of the active material, and finally including a process of further carbonizing, having a core-shell structure An object of the present invention is to provide a method for producing an active material composite for a secondary battery, characterized in that the composite for an active material for a secondary battery is prepared.

In addition, the present invention is manufactured by the above manufacturing method, the core comprising an active material containing an oxide (Core); and a shell in which a polycyclic hydrocarbon positioned on the surface of the active material and having at least five aromatic rings and a functional group having a specific chemical formula are bonded to each other by π-π-interaction; An object of the present invention is to provide an active material composite for a secondary battery.

The object of the present invention is not limited to the object mentioned above. The object of the present invention will become clearer from the following description, and will be realized by means and combinations thereof described in the claims.

A method for manufacturing an active material composite for a secondary battery according to an embodiment of the present invention includes preparing silicon nanoparticles and an active material including an oxide of the silicon nanoparticles on a surface of the silicon nanoparticles as a core; placing a functional group represented by the following Chemical Formula 1 into the active material, and locating the functional group on the surface of the active material; and a polycyclic hydrocarbon including five or more aromatic rings is added to the active material in which the functional group is located on the surface to form a shell on the surface of the active material, and has a core-shell structure Obtaining an active material composite for a secondary battery; includes, wherein the functional group and polycyclic hydrocarbon are coupled to each other by π-π-interaction to form a shell.

[Formula 1]

(R ₁ is each independently a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₁ -C ₁₀ alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted C ₅ -C ₁₄ is selected from the group consisting of a heteroaryl group and combinations thereof, n ₁ is 0 to 5, R ₂ is a halogen group, and the substituents of R ₁ are each independently a halogen group, a cyano group , a nitro group, a C ₁ -C ₈ alkyl group, and combinations thereof)

The active material may further include a hydroxyl group in the oxide of the silicon nanoparticles.

The active material may include an oxide of silicon nanoparticles and a hydroxyl group on a surface thereof, and the functional group may be positioned on the surface of the active material through hydrogen bonding with the functional group.

The polycyclic hydrocarbon including 5 or more aromatic rings is a hexabenzocoronene compound, a truxene compound, a decacyclene compound, an antanthrene compound, hexabenzotriphenylene (hexabenzotriphenylene) compound, 1,2,3,4,5,6,7,8-tetra-(ferri-naphthylene)-anthracene (1,2,3,4,5,6,7,8-tetra- It may include at least one selected from the group consisting of a (peri-naphthylene)-anthracene) compound, a dibenzoctacene compound, a tetrabenzoheptacene compound, and a peropyrene compound.

The hexabenzocoronene compound may be a compound represented by Formula 2 below.

[Formula 2]

(R ₁ to R ₄ are each independently a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₁ -C ₁₀ alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted C ₅ -C ₁₄ is selected from the group consisting of a heteroaryl group and combinations thereof, n ₁ to n ₄ are each independently 0 to 3, and the substituents of R ₁ to R ₄ are each independently a halogen group, It is selected from the group consisting of a cyano group, a nitro group, a C ₁ -C ₈ alkyl group, and combinations thereof)

The method for manufacturing the active material composite for a secondary battery may further include carbonizing the active material composite having a core-shell structure.

An active material composite for a secondary battery according to an embodiment of the present invention includes: a core including silicon nanoparticles, and an active material including an oxide of the silicon nanoparticles on a surface of the silicon nanoparticles; and a shell (Shell) comprising a polycyclic hydrocarbon positioned on the surface of the active material and having a functional group represented by the following Chemical Formula 1 and five or more aromatic rings, wherein the functional group and the polycyclic hydrocarbon are π-π- It is characterized in that they are combined with each other by interaction to form a shell.

[Formula 1]

(R ₁ is each independently a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₁ -C ₁₀ alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted C ₅ -C ₁₄ is selected from the group consisting of a heteroaryl group and combinations thereof, n ₁ is 0 to 5, R ₂ is a halogen group, and the substituents of R ₁ are each independently a halogen group, a cyano group , a nitro group, a C ₁ -C ₈ alkyl group, and combinations thereof)

The shell may be a carbonized shell.

The active material composite for a secondary battery prepared according to the present invention includes a shell in which a functional group having a specific chemical formula and a polycyclic hydrocarbon are bonded to each other by π-π-interaction on a core including an active material. Therefore, it is possible to control the volume expansion of the active material in the active material composite, as well as to ensure excellent stability and capacitance of a secondary battery including the same.

The effects of the present invention are not limited to the above-mentioned effects. It should be understood that the effects of the present invention include all effects that can be inferred from the following description.

1 is a flowchart schematically illustrating a method for manufacturing an active material composite for a secondary battery according to the present invention.
2 is a schematic diagram showing that benzoyl chloride, which is a functional group, is located on the surface of an active material according to an embodiment of the present invention.
FIG. 3a is a diagram schematically illustrating π-π-interaction between benzoyl chloride, a functional group located on the surface of an active material, and 4F-HBC, a polycyclic hydrocarbon, according to an embodiment of the present invention.
Figure 3b is a diagram showing that, according to an embodiment of the present invention, a functional group and a polycyclic hydrocarbon are bonded to each other by π-π-interaction to form a shell on a core that is an active material.
4A and 4B are SEM images of the active material composite for a secondary battery according to Example 2.
5 is a graph showing the results of Raman shift analysis of the active material composite for secondary batteries according to Examples 1 and 2 and the active material for secondary batteries according to Comparative Examples.
6a and 6b show a half battery prepared with the active material for a secondary battery according to Comparative Example ( FIG. 6a ) and a half battery prepared with the active material composite for a secondary battery according to Example 1 ( FIG. 6b ) under 0.1C conditions. It is a graph showing the voltage (V) with respect to the specific capacity after the third charge and discharge.

The above objects, other objects, features and advantages of the present invention will be easily understood through the following preferred embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

In describing each figure, like reference numerals have been used for like elements. In the accompanying drawings, the dimensions of the structures are enlarged than the actual size for clarity of the present invention.

In this specification, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, component, part, or a combination thereof described in the specification exists, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof. Also, when a part of a layer, film, region, plate, etc. is said to be “on” another part, it includes not only the case where the other part is “directly on” but also the case where there is another part in between. Conversely, when a part, such as a layer, film, region, plate, etc., is "under" another part, this includes not only cases where it is "directly under" another part, but also a case where another part is in the middle.

Unless otherwise specified, all numbers, values, and/or expressions expressing quantities of ingredients, reaction conditions, polymer compositions and formulations used herein, contain all numbers, values and/or expressions in which such numbers essentially occur in obtaining such values, among others. Since they are approximations reflecting various uncertainties in the measurement, it should be understood as being modified by the term "about" in all cases. Also, where the present disclosure discloses numerical ranges, such ranges are continuous and inclusive of all values from the minimum to the maximum inclusive of the range, unless otherwise indicated. Furthermore, when such ranges refer to integers, all integers inclusive from the minimum to the maximum inclusive are included, unless otherwise indicated.

In this specification, when a range is described for a variable, the variable will be understood to include all values within the stated range including the stated endpoints of the range. For example, a range of “5 to 10” includes the values of 5, 6, 7, 8, 9, and 10, as well as any subranges such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc. It will be understood to include any value between integers that are appropriate for the scope of the recited range, such as 5.5, 6.5, 7.5, 5.5 to 8.5 and 6.5 to 9, and the like. Also for example, ranges from "10% to 30%" include values of 10%, 11%, 12%, 13%, etc. and all integers up to and including 30%, as well as 10% to 15%, 12% to It will be understood to include any subranges such as 18%, 20% to 30%, etc., as well as any value between reasonable integers within the scope of the recited ranges, such as 10.5%, 15.5%, 25.5%, and the like.

There is a disadvantage that the life of the secondary battery is significantly reduced as the volume of the negative electrode material expands during charging and discharging of the conventional secondary battery.

Accordingly, as a result of intensive research to solve the above problem, the present inventors prepare an active material containing an oxide as a core, place a functional group having a specific chemical formula on the surface of the active material, and then include 5 or more aromatic rings By adding a polycyclic hydrocarbon, the functional group and the polycyclic hydrocarbon are combined with each other by π-π-interaction, thereby forming a shell on the surface of the active material, and finally including a process of additional carbonization, core When an active material composite for a secondary battery having a (Core)-shell structure is manufactured, it is possible to control the volume expansion of the active material in the active material composite for a secondary battery, as well as stability and capacitance of a secondary battery including the same It was confirmed that it can be secured excellently, and the present invention was completed.

Unless otherwise specified herein, "C ₁ -C ₁₀ alkyl group" means a primary to tertiary alkyl group having 1 to 10 carbon atoms. The alkyl group may be, for example, a functional group such as methyl, ethyl, n -propyl, i -propyl, n -butyl, i -butyl, tert -butyl, n -hexyl, or the like.

Unless otherwise specified herein, "C ₁ -C ₁₀ alkoxy" refers to the group -OR, wherein R includes "C ₁ -C ₁₀ alkyl" or "aryl" or "heteroaryl" or "benzyl" do. Preferred alkoxy groups include, for example, methoxy, ethoxy, phenoxy, benzyloxy and the like.

Unless otherwise specified in the present specification, an aryl group refers to a chemical group obtained by removing one hydrogen atom from a monocyclic or polycyclic compound having 2 to 30 carbon atoms and derivatives thereof containing one or more benzene rings, for example, The monocyclic or polycyclic compound containing the benzene ring is a benzene ring, toluene or xylene with an alkyl side chain attached to the benzene ring, biphenyl, etc. in which two or more benzene rings are bonded by a single bond, and the benzene ring is a cycloalkyl group or a hetero and fluorene, xanthene or anthraquinone condensed with a cycloalkyl group, and naphthalene or anthracene in which two or more benzene rings are condensed.

Unless otherwise specified herein, the prefix hetero means that 1 to 3 hetero atoms selected from the group consisting of -N-, -O-, -S- and -P- are substituted for carbon atoms. For example, it may be pyridine, pyrrole or carbazole containing a nitrogen atom as a hetero atom, furan or dibenzofuran containing an oxygen atom as a hetero atom, or the like, or dibenzothiophene, diphenylamine, and the like.

Unless otherwise specified herein, the halogen group refers to a group 17 element, and may be, for example, a fluoro group, a chloro group, a bromo group, or an iodo group.

Unless otherwise specified in the present specification, the bonding line at both ends of the formula without a substituent indicates a portion in which this compound is connected to another compound.

1 is a flowchart schematically illustrating a method for manufacturing an active material composite for a secondary battery according to the present invention. Referring to this, the step of preparing an active material containing an oxide as a core (Core) (S10); Putting the functional group represented by Chemical Formula 1 into the active material to position the functional group on the surface of the active material (S20); and a polycyclic hydrocarbon including five or more aromatic rings is added to the active material in which the functional group is located on the surface to form a shell on the surface of the active material, and has a core-shell structure Obtaining an active material composite for a secondary battery (S30); including, and carbonizing the active material composite having the core-shell structure (S40); may further include.

The step of preparing the active material as a core ( S10 ) is a step of preparing an active material including an oxide as a core.

The active material may vary depending on the polarity, and in the case of the anode active material, as a carbon-based active material, a carbon material such as natural graphite, artificial graphite, graphite carbon fiber, or plastic resin carbon, or an alloy-based material compounded with a solid electrolyte is used. can Examples of the alloy-based material include lithium alloys (LiAl, LiZn, Li ₃ Bi, Li ₃ Cd, Li ₃ Sb, Li ₄ Si, Li _4.4 Pb, Li _4.4 Sn, Li _0.17 C, LiC ₆ , etc.) and titanic acid. and metal oxides such as lithium (Li ₄ Ti ₅ O ₁₂ ) and Zn. Preferably, the metalloid silicon (Si) nanoparticles may include an oxide of silicon nanoparticles due to natural oxidation (native oxide) on the surface of the silicon nanoparticles. Specifically, the oxide of the silicon nanoparticles may include SiO ₂ and other oxides of silicon nanoparticles due to natural oxidation (native oxide). In addition, in the case of a positive active material, it may be an oxide active material or a sulfide active material, and the oxide active material is LiCoO ₂ , LiMnO ₂ , LiNiO ₂ , LiVO ₂ , Li _1+x Ni _1/3 Co _1/3 Mn _1/3 O ₂ , etc. rock salt layer type active material of LiMn ₂ O ₄ , Li(Ni _0.5 Mn _1.5 )O ₄ etc. spinel type active material, LiNiVO ₄ , LiCoVO ₄ reverse spinel type active material, LiFePO ₄ , LiMnPO ₄ , LiCoPO ₄ , LiNiPO ₄ Silicon-containing active material such as olivine-type active material, Li ₂ FeSiO ₄ , Li ₂ MnSiO ₄ , LiNi _0.8 Co _(0.2-x) Al _x O ₂ (0<x<0.2) Rock salt layer-type active material, Li _1+x Mn _2-xy M _y O ₄ (M is at least one of Al, Mg, Co, Fe, Ni, Zn, 0＜x+y＜2) It may be a spinel-type active material substituted with a metal, lithium titanate such as Li ₄ Ti ₅ O ₁₂ . The sulfide active material may be copper chevrel, iron sulfide, cobalt sulfide, nickel sulfide, or the like. Preferably, the active material is an anode active material, and may include silicon nanoparticles having a high charge/discharge capacity.

That is, since the active material according to the present invention may further include a hydroxyl group in the oxide of silicon nanoparticles located on the surface, the functional group can be positioned on the surface of the active material through hydrogen bonding with the functional group added in step S20. There is a characteristic.

The step of locating the functional group on the surface of the active material (S20) is a step of placing the functional group on the surface of the active material by introducing the functional group represented by the following Chemical Formula 1 into the active material.

Specifically, the functional group may be a compound represented by the following formula (1).

[Formula 1]

(R ₁ is each independently a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₁ -C ₁₀ alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted C ₅ -C ₁₄ is selected from the group consisting of a heteroaryl group and combinations thereof, n ₁ is 0 to 5, R ₂ is a halogen group, and the substituents of R ₁ are each independently a halogen group, a cyano group , a nitro group, a C ₁ -C ₈ alkyl group, and combinations thereof)

Preferably, n ₁ is 0, R ₂ may be a halogen group, and more preferably, R ₂ is a compound in which chlorine (Cl) is the most representative benzoyl chloride that attaches a benzoyl group to the active material.

2 is a schematic view showing that benzoyl chloride, which is a functional group, is located on the surface of an active material according to an embodiment of the present invention. Referring to this, benzoyl chloride may be positioned according to a specific arrangement on the surface of the active material.

Specifically, the functional group may be positioned in a specific arrangement through a hydrogen bond with a hydroxyl group located on the surface of the active material, and preferably, a representative benzoyl chloride having a monovalent benzoyl group (C ₆ H ₅ -COCl) is 2 Since it is a shorter form than the benzoyl group having more than , hydrogen bonding with the active material including an oxide is possible, so that the functional group can be more easily located on the surface of the active material.

As the functional groups are arranged in a predetermined arrangement on the surface of the active material, the functional groups can form a shell due to π-π-interaction with a polycyclic hydrocarbon including five or more aromatic rings to be added later in S30. have.

The content of the functional group is preferably in a mass ratio of active material: functional group of 4 to 5: 1. Out of the above range, if the content of functional groups is too small, there is a disadvantage that the shell cannot be completely formed. It has the disadvantage of not being able to achieve a structure.

In the step (S30) of obtaining an active material composite for a secondary battery having a core-shell structure, a polycyclic hydrocarbon including five or more aromatic rings is added to the active material in which the functional group is located on the surface, and the active material This is a step of forming a shell on the surface to obtain an active material composite for a secondary battery having a core-shell structure.

The polycyclic hydrocarbon including 5 or more aromatic rings is a hexabenzocoronene compound, a truxene compound, a decacyclene compound, an antanthrene compound, hexabenzotriphenylene (hexabenzotriphenylene) compound, 1,2,3,4,5,6,7,8-tetra-(ferri-naphthylene)-anthracene (1,2,3,4,5,6,7,8-tetra- A (peri-naphthylene)-anthracene) compound, a dibenzoctacene compound, a tetrabenzoheptacene compound, and a peropyrene compound may be one comprising at least one selected from the group consisting of, Preferably, it may include a hexabenzocoronene compound, and more preferably, the hexabenzocoronene compound may be a compound represented by Formula 2 below.

[Formula 2]

(R ₁ to R ₄ are each independently a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₁ -C ₁₀ alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted C ₅ -C ₁₄ is selected from the group consisting of a heteroaryl group and combinations thereof, n ₁ to n ₄ are each independently 0 to 3, and the substituents of R ₁ to R ₄ are each independently a halogen group, It is selected from the group consisting of a cyano group, a nitro group, a C ₁ -C ₈ alkyl group, and combinations thereof)

Specifically, in the hexabenzocoronene compound, n ₁ to n ₄ are each independently 1, and R ₁ to R ₄ are Each independently a halogen group, preferably, fluoro (F) may be 4F-hexabenzocoronene (4F-hexabenzocoronene; 4F-HBC).

The content of the polycyclic hydrocarbon is preferably set to a mass ratio of polycyclic hydrocarbon: functional group of 1: 20 to 100. Outside the above range, if the content of polycyclic hydrocarbon is too small, the shell structure does not completely cover the core, and if the content is too large, it is not possible to form a shell of uniform thickness or functional group There is a disadvantage of remaining as an impurity because pi-pi bonding is not possible.

Preferably, after adding the polycyclic hydrocarbon containing 5 or more aromatic rings, the temperature may be 80 ~ 120 ℃, preferably, by applying heat to a temperature of 100 ~ 120 ℃ (Shell) can be formed. Out of the above range, if the heating temperature is too low, the binding active energy cannot be reached and a core-shell structure cannot be formed. There is a disadvantage that it becomes difficult to uniformly coat.

Figure 3a is a diagram schematically showing the π-π- interaction between benzoyl chloride, a functional group located on the surface of an active material, and 4F-HBC, a polycyclic hydrocarbon, according to an embodiment of the present invention, FIG. 3b is According to an embodiment of the present invention, a functional group and polycyclic hydrocarbon are bonded to each other by π-π-interaction, and is a diagram showing that a shell is formed on a core, which is an active material.

Referring to FIG. 3A , the functional group benzoyl chloride includes an aromatic ring, and the polycyclic hydrocarbon 4F-HBC also includes an aromatic ring. At this time, each aromatic ring may be bonded to each other in a structure in which the planar aromatic rings are stacked by π-π-interaction. Due to the stacked structure, finally, as shown in FIG. 3b , the functional group and the polycyclic hydrocarbon may be combined with each other by π-π-interaction to form a shell on the core, which is the active material.

That is, the active material composite for a secondary battery prepared according to the present invention is a shell formed by bonding a functional group having a specific chemical formula and a polycyclic hydrocarbon to each other by π-π-interaction on a core including an active material. Since it contains, there is an advantage that it is possible to control the volume expansion of the active material in the active material composite.

In addition, the present invention may further include a step of carbonizing the active material composite for a secondary battery having the core-shell structure (S40); This is to secure the stability of the battery cell and relatively high capacitance through volume expansion control of silicon particles by performing the carbonization.

Specifically, in the carbonizing, the carbonization may be performed by applying heat to the active material composite for a secondary battery having the core-shell structure at a temperature of 900 to 1000°C. Outside the above range, there is a disadvantage that the carbon layer cannot be formed when the carbonization temperature is too low, and the active material composite is damaged when the carbonization temperature is too high.

That is, by carbonizing the active material composite for a secondary battery having a core-shell structure, there is an advantage in that volume expansion control of the active material in the active material composite can be better secured.

The active material composite for a secondary battery according to the present invention includes: a core including silicon nanoparticles and an active material including an oxide of the silicon nanoparticles on a surface of the silicon nanoparticles; and a shell including a polycyclic hydrocarbon positioned on the surface of the active material and including a functional group represented by the following Chemical Formula 1 and five or more aromatic rings. Preferably, the functional group and the polycyclic hydrocarbon are bonded to each other by π-π-interaction to form a shell.

[Formula 1]

(R ₁ is each independently a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₁ -C ₁₀ alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted C ₅ -C ₁₄ is selected from the group consisting of a heteroaryl group and combinations thereof, n ₁ is 0 to 5, R ₂ is a halogen group, and the substituents of R ₁ are each independently a halogen group, a cyano group , a nitro group, a C ₁ -C ₈ alkyl group, and combinations thereof)

The active material, the functional group, and the polycyclic hydrocarbon including five or more aromatic rings may be the same as or different from those described in the preparation method.

In addition, the active material composite for a secondary battery is carbonized, and the shell may be a carbonized shell.

That is, the active material composite for a secondary battery prepared according to the present invention is a shell formed by bonding a functional group having a specific chemical formula and a polycyclic hydrocarbon to each other by π-π-interaction on a core including an active material. Since it contains, it is possible not only to control the volume expansion of the active material in the active material composite, but also to ensure excellent stability and capacitance of a secondary battery including the same.

The present invention will be described in more detail with reference to the following examples. The following examples are only examples to help the understanding of the present invention, and the scope of the present invention is not limited thereto.

Example 1: Preparation of active material composite for secondary battery

(S10) 20 mg of silicon nanoparticles (Silicon, Si) were prepared as an active material. At this time, on the surface of silicon (Si), a hydroxyl group was included in the oxide of silicon nanoparticles, which is a native oxide.

(S20) Benzoyl chloride was prepared as a functional group, and 5 mL of a solution containing it was prepared, and then added to the prepared active material.

At this time, the mass ratio of the active material to the functional group was 4:1.

(S30) 4F-hexabenzocoronene (4F-HBC) as a polycyclic hydrocarbon was prepared in a mass ratio of polycyclic hydrocarbon: functional group 1: 20 to 100, and then heated to a temperature of 120 ° C. was added, and finally, an active material composite for a secondary battery having a core-shell structure was obtained.

Example 2: Preparation of active material composite for secondary battery through carbonization step

Compared with Example 1, the secondary battery active material composite having a core-shell structure prepared in Example 1 was carbonized by applying heat at a temperature of 1000° C., and the shell was carbonized secondary An active material composite for a battery was prepared.

Comparative Example: Preparation of an active material for a secondary battery containing a conventional silicon active material

As the active material of Comparative Example, Silcon nanoparticles of Meliorum Technologies, Inc. were used.

Experimental Example 1: SEM image and Raman shift analysis of active material composite for secondary battery

An active material composite for a secondary battery was prepared according to Example 2, and the results of the structural analysis were shown in the SEM image and the Raman shift analysis graph.

Specifically, FIGS. 4A and 4B are SEM images of the active material composite for secondary batteries according to Example 2, and FIG. 5 is a Raman shift of the active material composite for secondary batteries according to Examples 1 and 2 and the active material for secondary batteries according to Comparative Examples. It is a graph showing the analysis result.

Referring to FIGS. 4A and 4B , it can be seen that the carbon layer is formed in the active material composite.

Referring to FIG. 5, unlike Example 1 and Comparative Example, in the active material composite for a secondary battery according to Example 2, specific peaks D and G can be additionally identified, which indicates that the peak contains carbon due to carbonization. , it can be confirmed that the carbon layer is formed due to carbonization.

Experimental Example 2: Half-cell analysis of active material composites for secondary batteries

Using the active material composite for secondary batteries according to Examples 1 and 2 and the active material for secondary batteries according to Comparative Examples, respectively, the active material according to Example 1, Example 2, or Comparative Example: carbon (denka): binder = 6:2 A slurry is prepared in a weight ratio of :2, coated by a doctor blade method, and compressed using a roll press. After that, it was dried in a vacuum oven at a temperature of 120° C. for 12 hours to prepare a half-cell containing the active material.

Specifically, the half-cell prepared with the active material composite for secondary batteries according to Example 1 and the half-cell prepared from the active material for secondary batteries according to Comparative Example were measured under a cut-off voltage in a voltage range of 0 to 1.5 V, and the result are shown in FIGS. 6A to 6B, respectively.

Specifically, FIGS. 6A and 6B show the half-cell prepared with the active material for secondary batteries according to Comparative Example ( FIG. 6A ) and the half-cell prepared with the active material composite for secondary batteries according to Example 1 ( FIG. 6B ) under 0.1C conditions. It is a graph showing the voltage (V) with respect to the specific capacity (specific capacity) after the first to third charge and discharge.

Referring to FIGS. 6A to 6B , it can be seen that the specific capacity is relatively high in the half-cell prepared with the active material composite for secondary batteries according to Example 1, compared to the half-cells prepared with the active material for general secondary batteries. could

In addition, FIG. 7 shows the discharge specific capacity for the cycle number of the half battery prepared with the active material for secondary batteries according to Comparative Example and the half battery prepared with the active material composite for secondary batteries according to Example 2; and This is a graph showing the coulombic efficiency.

Referring to FIG. 7, compared to the half-cell prepared with the active material for a general secondary battery, in the half-cell prepared with the active material composite for secondary battery according to Example 2, the discharge specific capacity is high for all cycles, and it is stably maintained during the coulombic efficiency. could confirm that

That is, the active material composite for a secondary battery prepared according to the present invention is a shell formed by bonding a functional group having a specific chemical formula and a polycyclic hydrocarbon to each other by π-π-interaction on a core including an active material. Since it contains, it is possible not only to control the volume expansion of the active material in the active material composite, but also to ensure excellent stability and capacitance of a secondary battery including the same.

Claims (13)

preparing an active material including silicon nanoparticles and an oxide of the silicon nanoparticles on a surface of the silicon nanoparticles as a core;
placing a functional group represented by the following Chemical Formula 1 into the active material, and locating the functional group on the surface of the active material; and
A polycyclic hydrocarbon including five or more aromatic rings is added to the active material in which the functional group is located on the surface, and a shell is formed on the surface of the active material to form a core-shell structure. Including; obtaining a battery active material composite;
The functional group and polycyclic hydrocarbon are combined with each other by π-π-interaction to form a shell (Shell), the active material composite manufacturing method for a secondary battery.
[Formula 1]

(R ₁ is each independently a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₁ -C ₁₀ alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted C ₅ -C ₁₄ is selected from the group consisting of heteroaryl groups and combinations thereof,
n ₁ is 0 to 5,
R ₂ is a halogen group, and
The substituents of R ₁ are each independently selected from the group consisting of a halogen group, a cyano group, a nitro group, a C ₁ -C ₈ alkyl group, and combinations thereof) According to claim 1,
The active material is an active material composite manufacturing method for a secondary battery further comprising a hydroxyl group (Hydroxy group) in the oxide of the silicon nanoparticles. 3. The method of claim 2,
The active material includes an oxide of silicon nanoparticles and a hydroxyl group on the surface, and the functional group is located on the surface of the active material through hydrogen bonding with the functional group. According to claim 1,
The polycyclic hydrocarbon including 5 or more aromatic rings is a hexabenzocoronene compound, a truxene compound, a decacyclene compound, an antanthrene compound, hexabenzotriphenylene (hexabenzotriphenylene) compound, 1,2,3,4,5,6,7,8-tetra-(ferri-naphthylene)-anthracene (1,2,3,4,5,6,7,8-tetra- (peri-naphthylene)-anthracene) compound, dibenzoctacene compound, tetrabenzoheptacene compound, and peropyrene compound for a secondary battery comprising at least one selected from the group consisting of A method for producing an active material composite. 5. The method of claim 4,
The hexabenzocoronene (hexabenzocoronene) compound is a compound represented by the following formula (2), the active material composite manufacturing method for a secondary battery.
[Formula 2]

(R ₁ to R ₄ are each independently a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₁ -C ₁₀ alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted C ₅ -C ₁₄ is selected from the group consisting of heteroaryl groups and combinations thereof,
n ₁ to n ₄ are each independently 0 to 3, and
The substituents of R ₁ to R ₄ are each independently selected from the group consisting of a halogen group, a cyano group, a nitro group, a C ₁ -C ₈ alkyl group, and combinations thereof) According to claim 1,
In the step of forming the shell (Shell),
A method for producing an active material composite for a secondary battery, which is to form a shell by applying heat at a temperature of 80 to 120°C. According to claim 1,
The method for producing an active material composite for a secondary battery further comprising; carbonizing the active material composite having the core-shell structure. a core including silicon nanoparticles, and an active material including an oxide of the silicon nanoparticles on a surface of the silicon nanoparticles; and
A shell (Shell) comprising a polycyclic hydrocarbon located on the surface of the active material and containing a functional group represented by the following Chemical Formula 1, and five or more aromatic rings;
The functional group and polycyclic hydrocarbon are combined with each other by π-π-interaction to form a shell (Shell).
[Formula 1]

(R ₁ is each independently a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₁ -C ₁₀ alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted C ₅ -C ₁₄ is selected from the group consisting of heteroaryl groups and combinations thereof,
n ₁ is 0 to 5,
R ₂ is a halogen group, and
The substituents of R ₁ are each independently selected from the group consisting of a halogen group, a cyano group, a nitro group, a C ₁ -C ₈ alkyl group, and combinations thereof) 9. The method of claim 8,
The active material is an active material composite for a secondary battery further comprising a hydroxyl group in the oxide of the silicon nanoparticles. 9. The method of claim 8,
The active material includes an oxide of silicon nanoparticles and a hydroxyl group on the surface, and the functional group is positioned on the surface of the active material through hydrogen bonding with the functional group. 9. The method of claim 8,
The polycyclic hydrocarbon including 5 or more aromatic rings is a hexabenzocoronene compound, a truxene compound, a decacyclene compound, an antanthrene compound, hexabenzotriphenylene (hexabenzotriphenylene) compound, 1,2,3,4,5,6,7,8-tetra-(ferri-naphthylene)-anthracene (1,2,3,4,5,6,7,8-tetra- (peri-naphthylene)-anthracene) compound, dibenzoctacene compound, tetrabenzoheptacene compound, and peropyrene compound for a secondary battery comprising at least one selected from the group consisting of active material complex. 12. The method of claim 11,
The hexabenzocoronene compound is an active material composite for a secondary battery which is a compound represented by the following Chemical Formula 2.
[Formula 2]

(R ₁ to R ₄ are each independently a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₁ -C ₁₀ alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted C ₅ -C ₁₄ is selected from the group consisting of heteroaryl groups and combinations thereof,
n ₁ to n ₄ are each independently 0 to 3, and
The substituents of R ₁ to R ₄ are each independently selected from the group consisting of a halogen group, a cyano group, a nitro group, a C ₁ -C ₈ alkyl group, and combinations thereof) 9. The method of claim 8,
The shell is a carbonized shell active material composite for a secondary battery.

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