KR20130032818A - Electrode active material, electrode comprising the same, lithium battery comprising the electrode, and method for preparing the electrode active material - Google Patents

Abstract

PURPOSE: An electrode active material is provided to offer a lithium battery with excellent storage stability, lifetime, and high voltage performance at high temperature by regularly arranging pores. CONSTITUTION: An electrode active material(10) with a nanostructure comprises a core(12) which includes one or more from metal or metal oxides capable of emitting and absorbing lithium ions; and a crystalline carbon thin film(14) which is formed on at least a part of the core surface. The electrode active material includes pores(16) and walls among the pores. The pore includes one or more of SnO2 and MoO2. The thickness of the crystalline carbon thin film is 2nm or less. The specific surface area of the electrode active material is 50-250 m^2/g.

Description

[0001] The present invention relates to an electrode active material, an electrode including the electrode active material, a lithium battery including the electrode, and a method for manufacturing the electrode active material,

An electrode active material, an electrode including the electrode active material, a lithium battery employing the electrode, and a method for manufacturing the electrode active material.

A representative example of a negative electrode active material used in an electrochemical cell including a battery such as a lithium battery is a carbon-based material such as graphite. Graphite has excellent capacity retention characteristics and dislocation characteristics, and has no volume change when lithium and an alloy are formed, so that the stability of the battery is high.

On the other hand, a metal capable of alloying with lithium may be used as the negative electrode active material.

The metals which can be alloyed with lithium are Si, Sn, Al and the like. The metals capable of being alloyed with lithium are relatively large in electrical capacity, but the metals capable of alloying with lithium are accompanied by volume expansion during charging and discharging, resulting in short-circuited active materials in the electrode, thereby reducing the capacity retention characteristic of the battery .

There is an increasing need to develop an anode active material with improved performance in order to realize a high capacity and long life battery.

One aspect is to provide an electrode active material of a novel structure.

Another aspect is to provide an electrode including the electrode active material.

Another aspect is to provide a lithium battery employing the electrode.

Another aspect provides a method for producing the electrode active material.

According to an aspect of the present invention, there is provided a lithium secondary battery comprising: a core including at least one of metal and metal oxides capable of intercalating and deintercalating lithium ions; And a crystalline carbon thin film formed on at least a part of the surface of the core, wherein the electrode active material has a nano-structure.

According to another aspect, an electrode including the electrode active material is provided.

According to another aspect, there is provided a lithium battery including the electrode.

According to another aspect,

A core containing at least one of metal and metal oxides capable of intercalating and deintercalating lithium ions, a carbonaceous precursor represented by Chemical Formula 1, and a solvent are mixed to prepare a carbon-based moiety represented by the following Chemical Formula 2 ; And heat-treating the core formed with the carbon-based moiety in an inert atmosphere to convert the carbon-based moiety into a crystalline carbon thin film.

&Lt; Formula 1 > < EMI ID =

Among the above general formulas (1) and (2)

Ring A is a substituted or unsubstituted C ₅ -C ₃₀ aromatic ring or a substituted or unsubstituted C ₂ -C ₃₀ heteroaromatic ring;

a and b are each independently an integer of 1 to 5;

* Is a binding site with the core surface.

The lithium battery employing the electrode active material may have excellent capacity and life characteristics.

FIG. 1A schematically shows a part of one embodiment of the electrode active material, and FIG. 1B is a cross-sectional view schematically showing a cross section of the electrode active material shown in FIG. 1A.
2 is a schematic view showing an embodiment of the lithium battery.
3 is a transmission electron microscope (TEM) photograph of the active material of Comparative Example 1 observed.
4A and 4B are TEM photographs of the active material of Example 3. FIG.
5A and 5B are TEM photographs of the active material of Example 4. FIG.
6 is a TEM photograph of the active material of Comparative Example 8 observed.
7 is a TEM photograph showing the active material of Example 9. Fig.
Fig. 8 shows the X-ray diffraction results of the active materials of Comparative Examples 1, 3 and 5 to 7 at low angles.
Fig. 9 is a high-angle X-ray diffraction experiment result of the active materials of Comparative Example 1, Example 3, and Comparative Examples 5 to 7. Fig.
10 shows the X-ray diffraction experimental results of the active material of Comparative Example 1 and Examples 1 to 4.
Fig. 11 shows X-ray diffraction results of the active materials of Comparative Examples 8 and 7 to 10. Fig.
12 is a pore size distribution diagram of the active material of Comparative Example 1 and Examples 1 to 4.
13 is a pore size distribution diagram of the active material of Comparative Example 8 and Examples 7 to 10.
14 is a Raman spectrum of the active material of Comparative Example 2, Examples 5 and 6. Fig.
15 is a Raman spectrum of the active material of Example 3 and Comparative Example 6. Fig.
16 is a thermogravimetric analysis (TGA) result of the active material of Comparative Example 1 and Examples 1 to 4.
17 is the conductivity data of the spherical particle type SnO ₂ core without pores, and the active material of Comparative Example 2 and Example 5. Fig.
18 is the conductivity data of the active material of Comparative Example 1, Comparative Example 5 and Example 3. Fig.
19 is a graph showing the relationship between the first cycle charging / discharging curve of a lithium battery employing a negative electrode containing the active materials of Comparative Examples 1 and 3, Cycle charge / discharge curve.
20 is a graph of capacity retention (%) of a lithium battery employing a negative electrode containing the active materials of Comparative Example 1 and Examples 1 to 4, respectively.
21 is a graph of capacity retention (%) of a lithium battery employing a negative electrode containing the active materials of Comparative Examples 8 and 7 to 10, respectively.

Hereinafter, an electrode active material according to exemplary embodiments, an electrode including the electrode active material, a lithium battery and a capacitor employing the electrode, and a method for manufacturing the electrode active material will be described in detail.

The electrode active material according to one embodiment includes a core including at least one of metals and metal oxides capable of intercalating and deintercalating lithium ions, and a crystalline carbon thin film formed on at least a portion of the core surface, and may have a nano-structure .

The nano-structured electrode active material may have the form of particles, rods, wires or tubes. On the other hand, the nano-structured electrode active material may include pores and skeletons forming walls between the pores.

The term "nano-structured electrode active material" in the present specification means that at least one of the dimensions of the electrode active material is nano-sized (within a range of 100 nm or less, for example, 1 nm to 80 nm, In the range of 5 nm to 50 nm). For example, when the nano-structured electrode active material has a particle shape, the average particle size of the nano-structured electrode active material may have a nanosize as described above. When the nano-structured electrode active material has a particle shape and includes a skeleton that forms a wall between pores and pores, the average particle size of the particles, the average particle size of the pores, and the thickness of the skeleton are as described above It can have the same nano-size.

Since the electrode active material has a nano-structure as described above, lithium ions can be easily absorbed and released from the electrode active material. In addition, the electrode active material can be uniformly dispersed in the electrode including the electrode active material. Accordingly, the electrode including the nano-structured electrode active material can have improved electrical characteristics.

When the electrode active material includes pores and a skeleton forming a wall between the pores, the shape and distribution of the pores may be uniform. Thus, the electrode active material may have an ordered porosity. The pore size and skeletal thickness may have a nano size as described above.

When the electrode active material includes pores, the stress due to the volume expansion of the electrode active material during charging and discharging can be easily accommodated. In addition, since the specific surface area of the electrode active material can be greatly increased by the pores, the contact area between the electrode active material and the electrolyte can be increased. Here, when the skeleton thickness is nano-sized (for example, 10 nm or less), the diffusion path in the skeleton of the lithium ion is shortened and the high-rate characteristics can be improved.

On the other hand, when the electrode active material includes pores and skeletons as described above, nanoparticles of the same size as the skeleton cause resistance between the particles, but since the skeleton of the electrode active material forms a network, So that the power loss can be reduced. Since the pores of the electrode active material are regularly arranged, a uniform electrochemical reaction can be performed, and local loss or deterioration of the electrode active material can be avoided.

The core included in the electrode active material may include at least one of metals and metal oxides capable of intercalating and deintercalating lithium ions. The metal and the metal oxide may have a component capable of attaching a hydroxyl group on the surface thereof for dehydration reaction with the carbon-based precursor of the formula (1) to be described later.

The metal may include at least one of Sn, Fe, Co, Ni, Zn, Mn, Mo, and Bi. And the metal oxide may include at least one of tin oxide, iron oxide, cobalt oxide, nickel oxide, zinc oxide, manganese oxide, molybdenum oxide and bismuth oxide. The core may be an alloy or an oxide complex containing two or more different metals, and may be complexed with lithium.

For example, the core may include, but is not limited to, one or more of SnO ₂ and MoO ₂ .

The crystalline carbon thin film may be formed on at least a part of the surface of the core to improve the rate characteristics and the conductivity of the electrode active material. In addition, the crystalline carbon thin film plays a role of supporting the volume change of the core when the core expands in the charging and discharging process of the electrode active material, thereby reducing the physical structure change of the electrode active material. Thus, the lifetime characteristics of the lithium battery employing the electrode including the electrode active material can be improved.

The thickness of the crystalline carbon thin film may be 2 nm or less, for example, 0.1 nm to 2 nm or less. According to one embodiment, the thickness of the crystalline carbon thin film may be 1 nm or less, for example, 0.1 nm to 1 nm or less, but is not limited thereto.

Some or more of the crystalline carbon thin films may comprise single or multiple graphene layers. "Graphene" is a compound having a two-dimensional atomic plane structure in which carbon atoms are spontaneously sp 2 bonded. Thus, the thickness of the single graphene layer may be substantially equal to the diameter of the carbon atoms. The multiple graphene layer is a layer in which a plurality of graphene layers are stacked along a direction perpendicular to the direction in which carbon of one graphene layer extends. The multiple graphene layer may be a layer in which 2 to 10 grapins, for example, 2 to 5 graphenes, are laminated. Therefore, the thickness of the crystalline carbon thin film may be 1 to 10 times the diameter of the carbon atom, for example, 1 to 5 times the diameter of the carbon atom, and yet another example may be 1 to 2 times the diameter of the carbon atom , But is not limited thereto.

Since the crystalline carbon thin film has excellent crystallinity, the conductivity of the electrode active material can be improved. For example, the intensity of the D peak present at the wave number of 1360 10 cm ^-1 in the Raman spectrum of the crystalline carbon thin film is I _D , and the intensity of the G peak present at the wave number of 1580 10 cm ^-1 is I _G I _D / I _G may be 0.7 or less, for example, 0.65 or less. The D peak represents a disordered or defect of the carbon thin film, and the G peak represents a sp2 bond that is a graphite bond of the carbon thin film. The crystalline carbon thin film satisfying the I _D / I _G in the above-described range has excellent crystallinity, so that the conductivity of the electrode active material can be increased.

Therefore, the electrode active material has a specific surface area ranging from 31.83 Mpa to 2.0 x 10 ^-5 S / cm to 1.0 x 10 ^-2 S / cm, for example, from 7.1 x 10 ^-4 S / cm to 1.0 x 10 ^-3 S / cm Conductivity can be obtained. The electrode active material satisfies the above-described conductivity range while maintaining the nano-structure as described above, and thus can be usefully used in lithium batteries. The conductivity can be achieved by using, for example, a carbon-based precursor of the following formula (1) as a carbon thin film source.

When referred to a specific surface area of the core A, and La on the mass of the carbon thin film B, B / A is ^{7.69 x 10 -3 g 2 / m} 2 or less (wherein the carbon film is 10 yes pinned layer and the core is non- For example, 5.0 x 10 ^-4 g ² / m ² to 2.0 x 10 ^-4 g ² / m ² , which corresponds to a B / A value theoretically in the case of an active material having a surface area of 100 m ² / g. The B / A value is obtained because the carbon thin film has a uniform thickness with a fine thickness of, for example, 1 to 10 times the carbon atom diameter. For reference, in theory, the specific surface area of one graphene layer is 2600 m ² / g, and when one graphene layer is completely coated, B / A can have a value of 7.69 × 10 ^-4 g ² / m ² .

The electrode active material has the nano-structure and the carbon thin film as described above. 1A is an enlarged schematic view of a part of an electrode active material 10 including a pore 16 and a skeleton forming a wall between the pores 16 according to an embodiment, 1A is a schematic cross-sectional view of an electrode active material 10 shown in Fig. 1A. Fig. The electrode active material 10 includes a core 12 and a carbon thin film 14 and the carbon thin film 14 is formed on at least a part of the surface of the core 12. Specifically, the carbon thin film 14 is formed on the surface exposed to the outside of the core 12 and on the inner wall of the pores 16.

The pores 16 of the electrode active material 10 may have a bimodal size distribution. Since the pores 16 have a bimodal size distribution, the stress caused by the difference in the expansion ratio due to the internal structure difference of the electrode active material (for example, the core 12) during charging and discharging can be easily Can be accommodated. The fact that the pores 16 have a double size distribution means that two pore diameter peaks appear in the BJH (Barrett-Joyner-Halenda) pore size distribution obtained in the nitrogen adsorption experiment.

In a bimodal size distribution of the pores 16, the pores 16 may comprise a first peak in the range of 1 nm to 5 nm and a second peak in the range of 10 nm to 20 nm. For example, the pores may comprise a first peak in the range of 2 nm to 5 nm and a second peak in the range of 16 to 20 nm. That is, the electrode active material 10 may include regular first nano pores less than 10 nm and regular second nano pores larger than 10 nm.

The electrode active material 10 may have a regular mesoporous structure. The specific regularity of the pores 16 of the electrode active material 10 can be confirmed as a peak obtained in a low angle X-ray diffraction spectrum.

The electrode active material 10 may exhibit a peak for the (110) plane at a Bragg's 2? Angle of 0.6? 0.2? In a low angle X-ray diffraction spectrum.

For example, the electrode active material 10 exhibits a typical Tetragonal I4 ₁ / a (or its substructure) meso structure in a low angle X-ray diffraction spectrum. This represents a highly ordered three-dimensional pore structure and skeleton structure of the electrode active material 10. In particular, the diffraction peak for the (110) plane is related to the pore corresponding to the second peak in the double size distribution of the pores 16. [ That is, if pores corresponding to the second peak exist in the double-size distribution of the pores 16, a peak corresponding to the (110) plane exists in the low angle X-ray diffraction spectrum .

The thickness D of the skeleton forming the wall between the pores 16 of the electrode active material 10 may be 5 nm or more. For example, the thickness of the skeleton D may be 5 nm to 20 nm. For example, the thickness of the skeleton D may be 5 nm to 10 nm. For example, the thickness of the skeleton D may be 10 nm to 20 nm. For example, the thickness of the skeleton D may be 10 nm to 15 nm. When the thickness of the skeleton (D) satisfies the above-described range, the crystallization of the core 12 can be effectively performed.

The crystal size of the core 12 of the electrode active material 10 may be 5 nm or more. For example, the crystal size of the core 12 of the electrode active material 10 may be 5 nm to 30 nm.

The specific surface area of the electrode active material 10 may be 50 m ² / g to 250 m ² / g. For example, the specific surface area of the electrode active material 10 may be 100 m ² / g to 150 m ² / g. By having the specific surface area, the electrode active material 10 can contribute to improvement of electrical performance of a lithium battery, a capacitor, and the like. The specific surface area can be controlled by the size of the pores 16 or the size (or thickness) of the skeleton D. By satisfying the specific surface area, the lithium ion migration and diffusion path can be easily secured to the electrode active material 10, and the stability of the electrode active material 10 can be secured.

The volume of the pores 16 of the electrode active material 10 may be 0.1 cm ³ / g to 2 cm ³ / g. For example, the volume of the pores 16 of the electrode active material 10 may be 0.5 m ² / g to 1 cm ³ / g. By having the pore volume, the electrode active material 10 can contribute to improvement of the electrical performance of a lithium battery, a capacitor, and the like. The pore volume can be controlled by the size of the pores 16 or the size (or thickness) of the skeleton D. By satisfying the above-described pore volume range, it is possible to easily secure the migration and diffusion path of lithium ions to the electrode active material 10, and the stability of the electrode active material 10 can be secured.

In the electrode active material 10, the pores 16 may be connected to each other to form a channel. By the formation of such a channel, penetration of the electrolyte solution and movement of lithium ions into the electrode active material 10 can be facilitated.

The term "core surface" of the " crystalline carbon thin film formed on at least a part of the core surface " in the present specification is a term including the inner wall of the pore when the core includes a skeleton forming a wall between pores and pores .

The porosity of the electrode active material 10 may be 80% or less. For example, the porosity of the electrode active material 10 may be 10% to 70%. The porosity means the volume occupied by the pores 16 in the entire volume of the electrode active material 10. By satisfying the porosity range, the electrode active material 10 can have excellent life characteristics and energy density.

The electrode active material may be included in an electrode, for example, an electrode of a lithium battery. Accordingly, an electrode including the electrode active material is provided. The electrode may be a cathode or a cathode of a lithium battery, for example, a cathode of a lithium battery.

The negative electrode of the lithium battery can be manufactured according to the following process.

The negative electrode active material composition is prepared by mixing the electrode active material, the conductive agent, the binder and the solvent, and then directly coated on the copper current collector to prepare the negative electrode plate. Alternatively, the negative electrode active material composition may be cast on a separate support, and the negative electrode active material film peeled from the support may be laminated on a copper current collector to produce a negative electrode plate.

Examples of the conductive agent include carbon black, graphite fine particle natural graphite, artificial graphite, acetylene black, carbon fiber; Metal powders or metal fibers or metal tubes such as carbon nanotubes, copper, nickel, aluminum, and silver; Conductive polymers such as polyphenylene derivatives, and the like may be used, but the present invention is not limited thereto, and any conductive material may be used as the conductive material in the related art.

Examples of the binder include vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene (PTFE), a mixture of the above-mentioned polymers, a styrene butadiene rubber- Polymer, etc. may be used. As the solvent, N-methylpyrrolidone (NMP), acetone, water and the like may be used, but not limited thereto, and any of them can be used in the technical field.

In some cases, a plasticizer may be further added to the negative electrode active material composition to form pores in the electrode plate.

The content of the negative electrode active material, the conductive agent, the binder and the solvent is a level commonly used in a lithium battery. Depending on the application and configuration of the lithium battery, one or more of the conductive material, the binder, and the solvent may be omitted.

In addition, the negative electrode active material may further include other common negative electrode active materials in addition to the electrode active material. The general negative electrode active material may be any material that can be used as a negative electrode active material of a lithium battery in the related art. For example, the general negative electrode active material may include at least one selected from the group consisting of lithium metal, lithium-alloyable metal, transition metal oxide, non-transition metal oxide, and carbon-based material.

For example, the metal that can be alloyed with lithium is at least one element selected from the group consisting of Si, Sn, Al, Ge, Pb, Bi, Sb Si-X alloy (X is an alkali metal, an alkali earth metal, a Group 13 element, a Group 14 element, An element selected from the group consisting of Al, Al, and combinations thereof; and Sn is not an element other than Si), Sn-T alloy (T is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, a rare earth element, ) And the like. As the element X or Y, Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Pb, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof.

For example, the transition metal oxide may be lithium titanium oxide, vanadium oxide, lithium vanadium oxide, or the like.

For example, the non-transition metal oxide may be SnO ₂ , SiO _x (0 <x <2), or the like.

The carbon-based material may be crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon may be graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake, spherical or fibrous shape, and the amorphous carbon may be soft carbon or hard carbon carbon, mesophase pitch carbide, calcined coke, and the like.

In addition, the negative electrode may be suitably modified in its manufacturing method, electrode composition, electrode structure, and the like, except that it contains the above-described negative electrode active material for use in other electrochemical cells such as a supercapacitor in addition to a lithium battery.

For example, the electrode for a capacitor can be manufactured by disposing a metal structure on a conductive substrate and coating the above-described negative electrode active material on the metal structure. Alternatively, the anode active material may be directly coated on the conductive substrate.

The positive electrode containing the electrode active material can also be produced by a method similar to the above-described method using a material that can be included in a conventional lithium battery positive electrode.

A lithium battery according to another embodiment employs a positive electrode or a negative electrode including the electrode active material. For example, the lithium battery may employ a negative electrode including the electrode active material. Such a lithium battery can be manufactured, for example, as follows.

First, an anode including the electrode active material is prepared according to one embodiment as described above.

Next, the anode can be manufactured as follows. The anode may be manufactured in the same manner as the cathode except that the cathode is used as a cathode active material instead of the anode active material.

As the conductive agent, the binder and the solvent in the cathode active material composition, the same materials as those of the cathode can be used. A cathode active material composition, 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 on the aluminum current collector and dried to produce a positive electrode plate having a positive electrode active material layer. Alternatively, the cathode active material composition may be cast on a separate support, and then a film obtained by peeling the support from the support may be laminated on the aluminum current collector to produce a cathode plate having a cathode active material layer.

The cathode active material is a lithium-containing metal oxide, and any of those conventionally used in the art can be used without limitation. For example, one or more of complex oxides of metals selected from cobalt, manganese, nickel, and combinations thereof may be used. Specific examples thereof include Li _a A _{1 - b} L _b D ₂ In the formula, 0.90? A? 1.8, and 0? B? 0.5); Li _a E _{1 - b} L _b O _{2 - c} D _{c where} 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05; LiE _{2 - b} L _b O _{4 - c} D _{c where} 0? B? 0.5, 0? C? 0.05; Li _a Ni _{1 -b- c} Co _b L _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 L _c O _{2 - ?} R _{? Where} 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _{1 -b- c} Co _b L _c O _{2 - ?} R ₂ wherein 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? Li _a Ni _{1 -bc} Mn _b L _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 L _c O _2-α R _α wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 <α <2; Li _a Ni _{1 -b- c} Mn _b L _c O _{2 - ?} R ₂ wherein 0.90? A? 1.8, 0? B? 0.5, 0? C? 0.05, 0 <? 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 ; LiZO 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; L is at least one element selected from the group consisting of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements or combinations thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; R is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or combinations thereof; Q is Ti, Mo, Mn, or a combination thereof; Z 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 0.5, and 0≤y≤0.5), LiFePO ₄ or the like.

Of course, a compound having a coating layer on the surface of the compound may be used, or a compound having a coating layer may be mixed with the compound. 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.

The content of the cathode active material, the conductive agent, the binder, and the solvent is a level commonly used in a lithium battery. Next, a separator to be inserted between the positive electrode and the negative electrode is prepared. The separator is usable as long as it is commonly used in a lithium battery. A material having low resistance against the ion movement of the electrolyte and excellent in the ability to impregnate the electrolyte may be used. For example, selected from glass fibers, polyester, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), or a combination thereof, and may be nonwoven fabric or woven fabric. For example, a rewindable separator such as polyethylene, polypropylene, or the like is used for the lithium ion battery, and a separator having excellent organic electrolyte impregnation capability can be used for the lithium ion polymer battery. For example, the separator may be produced according to the following method.

A polymer resin, a filler and a solvent are mixed to prepare a separator composition. The separator composition may be coated directly on the electrode and dried to form a separator. Alternatively, after the separator composition is cast and dried on a support, a separator film peeled from the support may be laminated on the electrode to form a separator.

The polymer resin used in the production of the separator is not particularly limited, and any material used for the binder of the electrode plate may be used. For example, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate or mixtures thereof may be used.

Next, the electrolyte is prepared.

For example, the electrolyte may be an organic electrolyte. In addition, the electrolyte may be a solid. For example, boron oxide, lithium oxynitride, and the like, but not limited thereto, and any of them can be used as long as they can be used as solid electrolytes in the art. The solid electrolyte may be formed on the cathode by a method such as sputtering.

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. Examples of the solvent include propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate (ethyl methyl carbonate), methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, The organic solvent is preferably selected from the group consisting of a carbonate, a dibutyl carbonate, a benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran,? -Butyrolactone, dioxolane, 4-methyldioxolane, Amides, dimethylsulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether or mixtures 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 , _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. 2, the lithium battery 1 includes an anode 3, a cathode 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-sized thin-film battery. The lithium battery may be a lithium ion battery.

A separator may be disposed between the anode and the cathode to form a battery structure. The cell structure is laminated in a bi-cell structure, then impregnated with an organic electrolyte solution, and the obtained result is received 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, a notebook, a smart phone, an electric vehicle, and the like.

Further, the lithium battery has excellent storage stability, lifetime characteristics and high-rate characteristics at high temperatures, and thus can be used in an electric vehicle (EV). For example, a hybrid vehicle such as a plug-in hybrid electric vehicle (PHEV).

A capacitor according to another embodiment employs a negative electrode including the electrode active material. For example, the capacitor may be a super capacitor having a very large capacitance.

The capacitor may employ a negative electrode including the above-described electrode active material. The capacitor can be manufactured by disposing an anode and a cathode, arranging a separator therebetween, and injecting an electrolyte into the separator. The anode is usable as long as it is used in the art.

The solvent used for the electrolytic solution may be one or more solvents selected from the group consisting of acetonitrile, dimethyl ketone, and propylene carbonate. The electrolyte used in the electrolytic solution is an alkali metal salt having a solubility of 0.01 mole / L or more in the solvent and electrically inactive in the operating voltage range of the capacitor. For example, lithium perchlorate, lithium tetrafluoroborate, lithium hexafluorophosphate, and the like. The electrolytic solution may contain additional additives for improving the physical properties of the capacitor. For example, stabilizers, thickeners, and the like.

Meanwhile, the lithium battery and / or the capacitor may include the electrode active material as a cathode active material.

The method for producing an electrode active material according to the present invention comprises the steps of: i) mixing a core containing at least one of metals and metal oxides capable of intercalating and deintercalating lithium ions, ii) a carbonaceous precursor represented by formula 1, and iii) Forming a carbon-based moiety represented by Formula 2 at least partially; And heat-treating the core formed with the carbon-based moiety in an inert atmosphere to convert the carbon-based moiety into a crystalline carbon thin film.

&Lt; Formula 1 > < EMI ID =

In Formulas 1 and 2, ring A is a substituted or unsubstituted C ₅ -C ₃₀ aromatic ring or a substituted or unsubstituted C ₂ -C ₃₀ hetero aromatic ring; a and b are each independently an integer of 1 to 5; * Is a binding site with the core surface.

A detailed description of the core contained in the mixture is given above. The core may have a nano-structure as described above. For example, when the core having the nano-structure has a particle shape, the average particle diameter of the core having the nano-structure may have a nano-size as described above. When the core having the nano-structure has a particle shape and includes a skeleton forming a wall between the pores and the pores, the average particle size of the core, the average particle size of the pores, It can have nano size.

According to one embodiment of the method for producing a core having pores, the core may include a step of impregnating a liquid containing a precursor of the core, such as silica (SiO ₂ ), Al ₂ O ₃ , ZnO, MgO, ; Firing a liquid-impregnated porous template containing the precursor of the core to form a composite of the porous template-core; And removing the porous template from the composite of the porous template-core.

The porous template may have a nanostructure related to the nanostructure of the core to be produced.

The precursor of the core may be a nitride, a chloride, a sulfide, a salt (e.g., an ammonium salt), a cyanide, an oxide, or an alkoxide including a metal or a metal oxide included in the core. For example, when the core comprises SnO ₂ , the precursor of the core may contain a salt containing tin (e.g. Sn (NO ₃ ) ₂ .6H ₂ O, Sn (CH ₃ COO) ₂ .xH ₂ O Etc.) and a chloride including tin (for example, SnCl ₂ .xH ₂ O (where x is an integer such as SnCl ₂ .2H ₂ O (Tin (II) chloride dihydrate) But is not limited thereto. On the other hand, when the core contains MoO ₂ , the precursor of the core may be a salt containing Mo (for example, (NH ₄ ) ₆ Mo ₇ O ₂₄ .4H ₂ O (Ammonium molybdate tetrahydrate) But is not limited thereto.

The liquid containing the precursor of the core may be a melt obtained by heating the precursor of the core (for example, a melt of SnCl ₂ .2H ₂ O is used), or a precursor of the core may be dissolved in a solvent such as water or alcohol The resulting solution (for example, (NH ₄ ) ₆ Mo ₇ O ₂₄ .4H ₂ O may be an aqueous solution thereof).

The firing temperature of the firing step may be about 300 ° C to about 700 ° C. For example, the firing temperature may be from about 500 ° C to about 550 ° C. When the above range is satisfied, the crystallinity of the core of the porous template-core composite as a result of firing can be increased. The firing step may be performed in an oxidizing atmosphere or a reducing atmosphere. The reducing atmosphere may be an atmosphere containing at least one gas selected from the group consisting of nitrogen, argon, helium and hydrogen. The oxidizing atmosphere may be an atmosphere containing oxygen. For example, air.

The step of removing the porous template from the composite of the porous template-core may be performed by contacting the composite of the porous template-core with the etching solution. For example, the etchant may be selected from the group consisting of hydrofluoric acid (HF), NaOH, and HF-NH ₄ F (buffer), but is not limited thereto. The etchant may be an acid or a base.

The carbon-based precursor may include 1 to 5 hydroxyl groups as shown in Formula 1, and may include aromatic rings or heteroaromatic rings having a conjugation structure.

In Formula 1, ring A may be substituted or unsubstituted benzene, substituted or unsubstituted pentarenes, substituted or unsubstituted indene, substituted or unsubstituted naphthalene, substituted or unsubstituted azulene, Substituted or unsubstituted phenanthrene, substituted or unsubstituted anthracene, substituted or unsubstituted anthracene, substituted or unsubstituted anthracene, substituted or unsubstituted thiophene, , Substituted or unsubstituted fluoranthene, substituted or unsubstituted triphenylene, substituted or unsubstituted pyrene, substituted or unsubstituted chrysene, substituted or unsubstituted naphthacene, substituted or unsubstituted pysene, A substituted or unsubstituted pyrazole, a substituted or unsubstituted imidazole, a substituted or unsubstituted pyrazole, a substituted or unsubstituted pyrazole, a substituted or unsubstituted pyrazole, a substituted or unsubstituted pyrazole, a substituted or unsubstituted pyrazole, Substituted or unsubstituted imidazolidine, substituted or unsubstituted imidazopyrimidine, substituted or unsubstituted imidazopyrimidine, substituted or unsubstituted pyridine, substituted or unsubstituted pyrazine, substituted or unsubstituted pyrimidine, substituted or unsubstituted pyrimidine, A substituted or unsubstituted indoline, a substituted or unsubstituted indoline, a substituted or unsubstituted quinoline, a substituted or unsubstituted phthalazine, a substituted or unsubstituted indole, a substituted or unsubstituted naphthyridine, A substituted or unsubstituted quinazoline, a substituted or unsubstituted cinnoline, a substituted or unsubstituted indazole, a substituted or unsubstituted carbazole, a substituted or unsubstituted phenazine, a substituted or unsubstituted phenanthridine, a substituted or unsubstituted quinazoline, Or unsubstituted triazine, substituted or unsubstituted phenanthroline, or substituted or unsubstituted quinoxaline, but is not limited thereto.

When the ring A is a substituted C ₅ -C ₃₀ aromatic ring or a substituted or unsubstituted C ₂ -C ₃₀ heteroaromatic ring, the substituent may be a halogen atom, a cyano group, a carboxyl group or a salt thereof, a C ₁ -C ₁₀ alkyl group (E.g., methyl group, ethyl group, propyl group, butyl group and the like) or a C ₁ -C ₁₀ alkoxy group (for example, methoxy group, ethoxy group, propoxy group and butoxy group) It is not.

For example, the A ring may be a substituted or unsubstituted C ₅ -C ₃₀ aromatic ring or a substituted or unsubstituted C ₂ -C ₃₀ heteroaromatic ring fused to an unsubstituted six-membered ring only .

According to one embodiment, the A ring in Formula 1 is selected from the group consisting of benzene, naphthalene, phenalene, phenanthrene, anthracene, triphenylene, pyrene, chrysene, naphthacene, Examples of the organic solvent include picene, perylene, pentaphene, hexacene, pyridine, pyrazine, pyrimidine, pyridazine, quinoline, phthalazine, quinoxaline, quinazoline, Phenanthrene, a and b may be 1 or 2, but are not limited thereto.

The solvent may be selected from conventional solvents which are chemically unreactive with the core and the carbon precursor, can be removed at a relatively low temperature, and can serve as a medium capable of effectively contacting the core and the carbon precursor . As the solvent, acetone, ethanol, distilled water and the like can be used, but it is not limited thereto.

In the mixture, the core and the carbon-based precursor are in contact with each other, and as a result, the carbon-based moiety represented by Formula 2 may be bonded to the core surface. The carbon-based moiety may be formed as a result of a dehydration reaction between a hydroxyl group present on the surface of the core and a hydroxyl group of the carbon-based precursor.

The step of bonding the carbon-based moiety to the core surface may be carried out by preparing a mixture as described above. Alternatively, it may be carried out by a heat treatment step for promoting dehydration reaction between the hydroxyl group of the core surface and the hydroxyl group of the carbon-based precursor. The heat treatment conditions for promoting the dehydration reaction may vary depending on the composition and amount of the carbon precursor and the like. For example, in an inert atmosphere (for example, one or more of nitrogen, argon, helium, In the range of 100 占 폚 to 500 占 폚 and 1 hour to 5 hours.

Next, the core having the carbon-based moiety bonded to the surface is heat-treated in an inert atmosphere (for example, an atmosphere containing at least one of nitrogen, argon, helium, and hydrogen gas) By carbonizing the carbon-based moiety, the carbon-based moiety is converted into a crystalline carbon thin film as described above. Thus, the electrode active material including the core and the crystalline carbon thin film formed on at least a part of the core surface can be produced.

The heat treatment conditions of the core to which the carbon-based moiety is bonded on the surface will vary depending on the composition and amount of the selected core and the carbon-based precursor. For example, 300 to 600 占 폚 Lt; 0 &gt; C) and 1 hour to 5 hours (for example, 1 hour to 3 hours).

The carbon-based moiety of the core surface is bonded to the core surface with oxygen interposed therebetween as shown in Formula (2). On the core surface, a self-aligned monolayer composed of the carbon-based moiety of Formula 2 a self-assembled mono layer (SEM layer) can be formed. Since the self-aligned monolayer made of the carbon-based moiety of Formula 2 is converted into a crystalline carbon thin film as a result of the heat treatment, the crystalline carbon thin film of the electrode active material is very thin (for example, 2 nm or less) have. Therefore, as shown in FIG. 1B, a crystalline carbon thin film 14 having a thin and uniform thickness can be formed on the inner wall of the pores 16 having nano size.

The crystalline carbon thin film is obtained as a result of the heat treatment of the A ring of the carbon-based moiety of Formula 2. Since the A ring is an aromatic or heteroaromatic ring having a conjugation structure, the crystalline carbon thin film has excellent crystallinity Lt; / RTI &gt; The electrode active material including the crystalline carbon thin film formed from the carbon-based precursor of Formula 1 may have excellent conductivity.

In addition, the ring A of the carbon-based moiety of Formula 2 is an aromatic or heteroaromatic ring having a conjugation structure, and the heat treatment temperature required to convert it into a crystalline carbon thin film is relatively low. Generally, the higher the temperature at which the carbon-based compound is converted to the carbon thin film, the more the crystallinity of the carbon thin film can be increased. However, when the active material is exposed to high temperature, the crystal structure of the active material is changed, and the nanostructure of the active material (for example, pore collapse, etc.) may collapse. For example, as can be seen from the X-ray diffraction patterns (Figs. 8 and 9 (b) and (c)) of the active material of Comparative Examples 6 and 7 to be described later, And the crystal phase structure may be changed. However, the carbon-based precursor of Formula 1 contains an A ring having a conjugation structure and contains at least one hydroxyl group capable of binding to the core surface. The carbon-based precursor includes a core having a nanostructure and a low temperature Can be easily converted into carbon thin films having excellent crystallinity. This makes it possible to produce the electrode active material having a high conductivity while maintaining the nanostructure.

EXAMPLES The following examples and comparative examples illustrate exemplary embodiments in more detail. It should be noted, however, that the embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[Example]

(Active material production)

Example 1

SnCl ₂ .2H ₂ O was heated to melt the porous SiO ₂ (KIT-6, a molecular sieve material having a structure in which three-dimensional pores are interconnected). At this time, a SnCl ₂ .2H ₂ O melt was injected into the porous SiO ₂ so that the ratio of SnO ₂ to SiO ₂ was 40 parts by weight based on 100 parts by weight of the SiO ₂ . Subsequently, the porous SiO ₂ into which the SnCl ₂ .2H ₂ O was injected was fired at 550 ° C for 3 hours in an air atmosphere to obtain a SiO ₂ -SnO ₂ composite. The above complex was injected into a 10 wt% HF aqueous solution and reacted for 10 minutes. The reaction was repeated twice to remove the SiO ₂ template and then filtered to obtain a porous SnO ₂ core having a skeleton having a thickness of about 7 nm as shown in FIG.

1 g of the porous SnO ₂ core, 0.02 g of 2,3-dihydroxyl naphthalene (DN) as a carbon precursor, and 0.5 g of acetone as a solvent were mixed and stirred, and then the mixture (porous SnO ₂ core and carbon- The weight ratio of the precursor was 1: 0.02) was subjected to a first heat treatment at 200 ° C for 2 hours under an N ₂ atmosphere to promote the dehydration reaction between the core and DN, and then the temperature was raised to 500 ° C and the second heat treatment To prepare an active material having a carbon thin film formed on at least a part of the surface of the porous SnO ₂ core.

Example 2

An active material was prepared in the same manner as in Example 1 except that 0.04 g of a carbon-based precursor was used so that the weight ratio of the porous SnO ₂ core and the carbon-based precursor was 1: 0.04.

Example 3

An active material was prepared in the same manner as in Example 1, except that 0.06 g of a carbon-based precursor was used so that the weight ratio of the porous SnO ₂ core and the carbon-based precursor was 1: 0.06.

Example 4

An active material was prepared in the same manner as in Example 1, except that 0.08 g of a carbon-based precursor was used so that the weight ratio of the porous SnO ₂ core and the carbon-based precursor was 1: 0.08.

Example 5

Except that the porous SnO ₂ core was replaced with a spherical particle type SnO ₂ core having pores (manufactured by Aldrich, SnO ₂ particles having an average particle diameter of about 100 nm or less) was used. To prepare an active material.

Example 6

Except that the porous SnO ₂ core was replaced with a spherical particle type SnO ₂ core having pores (manufactured by Aldrich, SnO ₂ particles having an average particle diameter of about 100 nm or less) was used. To prepare an active material.

Example 7

Except that the porous MoO ₂ core prepared by using (NH ₄ ) ₆ Mo ₇ O ₂₄揃 4H ₂ O aqueous solution instead of the SnCl ₂揃 2H ₂ O melt was used instead of the porous SnO ₂ core To prepare an active material.

Example 8

Except that the porous MoO ₂ core prepared by using (NH ₄ ) ₆ Mo ₇ O ₂₄揃 4H ₂ O aqueous solution instead of the SnCl ₂揃 2H ₂ O melt was used in place of the porous SnO ₂ core To prepare an active material.

Example 9

Except that the porous MoO ₂ core prepared by using (NH ₄ ) ₆ Mo ₇ O ₂₄揃 4H ₂ O aqueous solution instead of the SnCl ₂揃 2H ₂ O melt was used instead of the porous SnO ₂ core To prepare an active material.

Example  10

Except that the porous MoO ₂ core prepared by using (NH ₄ ) ₆ Mo ₇ O ₂₄揃 4H ₂ O aqueous solution instead of the SnCl ₂揃 2H ₂ O melt was used instead of the porous SnO ₂ core To prepare an active material.

Comparative Example 1

The active material composed of the porous SnO ₂ core was prepared according to the method described in Example 1, except that the carbon thin film forming step was omitted.

Comparative Example 2

An active material was prepared in the same manner as in Example 5 except that sucrose instead of 2,3-dihydroxyl naphthalene was used.

Comparative Example 3

An active material was prepared in the same manner as in Example 5, except that sucrose was used instead of 2,3-dihydroxyl naphthalene and the second heat treatment temperature was changed to 700 ° C.

Comparative Example 4

An active material powder was prepared in the same manner as in Example 5 except that sucrose was used instead of 2,3-dihydroxyl naphthalene and the second heat treatment temperature was changed to 900 ° C.

Comparative Example 5

An active material was prepared in the same manner as in Example 3 except that sucrose was used instead of 2,3-dihydroxyl naphthalene.

Comparative Example 6

An active material was prepared in the same manner as in Example 3, except that sucrose was used instead of 2,3-dihydroxyl naphthalene and the second heat treatment temperature was changed to 700 ° C.

Comparative Example 7

An active material was prepared in the same manner as in Example 3, except that sucrose was used instead of 2,3-dihydroxyl naphthalene and the second heat treatment temperature was changed to 900 ° C.

Comparative Example 8

The active material composed of the porous MoO ₂ core was prepared according to the method described in Example 7, except that the carbon thin film forming step was omitted.

The active materials of Examples 1 to 10 and Comparative Examples 1 to 8 are summarized in the following Table 1:

Core component Core structure Precursor for forming a carbon-based thin film Core: precursor weight ratio Second heat treatment temperature (占 폚) Example 1 SnO ₂ Porous DN 1: 0.02 500 Example 2 SnO ₂ Porous DN 1: 0.04 500 Example 3 SnO ₂ Porous DN 1: 0.06 500 Example 4 SnO ₂ Porous DN 1: 0.08 500 Example 5 SnO ₂ Bulk (without porosity) DN 1: 0.06 500 Example 6 SnO ₂ Bulk (without porosity) DN 1: 0.08 500 Example 7 MoO ₂ Porous DN 1: 0.02 500 Example 8 MoO ₂ Porous DN 1: 0.04 500 Example 9 MoO ₂ Porous DN 1: 0.06 500 Example 10 MoO ₂ Porous DN 1: 0.08 500 Comparative Example 1 SnO ₂ Porous - - - Comparative Example 2 SnO ₂ Bulk (without porosity) Sucrose 1: 0.06 500 Comparative Example 3 SnO ₂ Bulk (without porosity) Sucrose 1: 0.06 700 Comparative Example 4 SnO ₂ Bulk (without porosity) Sucrose 1: 0.06 900 Comparative Example 5 SnO ₂ Porous Sucrose 1: 0.06 500 Comparative Example 6 SnO ₂ Porous Sucrose 1: 0.06 700 Comparative Example 7 SnO ₂ Porous Sucrose 1: 0.06 900 Comparative Example 8 MoO ₂ Porous - - -

Evaluation Example 1: Observation of active material

The active materials of Comparative Examples 1, 3, 4, 8 and 9 were observed with a high-resolution transmission electron microscope (HR-TEM). The results are shown in Fig. 3 (active material of Comparative Example 1) (Active material of Example 4), 4B (active material of Example 3), 5A and 5B (active material of Example 4), 6 (active material of Comparative Example 8) and 7 (active material of Example 9).

3 to 7, it can be confirmed that the active material powders have a porous structure.

4B, 5B and 7, it can be seen that the active materials of Examples 3, 4 and 9 are arranged regularly and include nano-sized pores connected to each other to form a channel. The thickness of the skeleton forming the walls between the nanopores is shown in Table 2 below:

The thickness of the skeleton forming the wall between the pores [nm] Example 3 7 ± 1 Example 4 7 ± 1 Example 9 7 ± 1

Evaluation Example 2: X-ray diffraction experiment

X-ray diffraction experiments using CuK? Were performed on the active materials of Comparative Examples 1, 3 and 5 to 7, and a small angle diffraction pattern and a high angle diffraction pattern are shown in FIGS. Respectively.

8 (a), Comparative Example 1 (porous core / carbon thin film not formed), Example 3 (carbon thin film formed using porous core / DN) heat-treated at 500 占 폚 and heat treated at 500 占 폚 The peak for the (110) plane of the active material of Example 5 (formed by a porous carbon / sucrose thin film) appears at Bragg 2 theta angle of 0.6 0.2 deg. And the peak for the (221) °. The (110) and (221) planes correspond to one side of a highly ordered three-dimensional skeletal structure and pore structure in porous SnO ₂ . The low angle X-ray diffraction spectrum is a diffraction pattern due to the arrangement of regular skeletal structures and pores having nano-size. 8 (a), Comparative Example 1 (porous core / carbon thin film not formed), Example 3 (carbon thin film formed using porous core / DN) heat-treated at 500 占 폚 and heat treatment at 500 占 폚 It can be seen that the active material of Example 5 (carbon thin film formed using porous core / sucrose) has a mesoporous structure with regular nano-sized pores.

However, according to FIGS. 8 (b) and 8 (c), Comparative Example 6 (a carbon thin film was formed by using a porous core / sucrose) heat-treated at 700 ° C and Comparative Example 7 The carbon thin film is formed by using a cross), the peak of the (110) plane and the (221) plane is not clear. From these results, it can be seen that the active material of Comparative Example 6 and Comparative Example 7 has a nanoscale structure of the porous SnO ₂ core before the carbon thin film formation using sucrose is largely collapsed, and has no more regular mesoporous structure . It can be interpreted that the nanostructure collapse is due to the high-temperature heat treatment (700 ° C and 900 ° C) for forming carbon thin films using sucrose.

According to FIG. 9A, a carbon thin film was formed by using a porous core / sucrose of Comparative Example 5 (heat treatment at 500 DEG C) in Example 3 (forming a carbon thin film by using porous core / DN) ) Had peaks at the same Bragg 2 &amp;thetas; positions as Comparative Example 1 (porous core / carbon thin film not formed). From this, the active material of Comparative Example 1 (porous carbon / thin film formed by using a porous core / sucrose) and Comparative Example 1 (porous core / Carbon thin film was not formed).

However, according to FIGS. 9 (b) and 9 (c), Comparative Example 6 (a carbon thin film formed by using porous core / sucrose) heat-treated at 700 ° C and Comparative Example 7 9 (b) and (c)) that are not observed in Fig. 9 (a). From this, it can be seen that the active materials of Comparative Examples 6 and 7 had a change in the crystal phase of the SnO ₂ core due to the high-temperature heat treatment (700 ° C. and 900 ° C.) for forming a carbon thin film using sucrose.

Fig. 10 shows X-ray diffraction results of the active materials of Comparative Example 1 and Examples 1 to 4; Fig. It can be seen from Fig. 10 that the active materials of Examples 1 to 4 using different amounts of the carbon-based precursor have the same X-ray diffraction pattern as that of Comparative Example 1. The active materials of Examples 1 to 4, It can be confirmed that the nanoporous structure is maintained.

Fig. 11 shows X-ray diffraction results of the active materials of Comparative Examples 8 and 7 to 10. Fig. 11 shows that the active materials of Examples 7 to 10 using different amounts of the carbon-based precursors have the same X-ray diffraction pattern as that of Comparative Example 8. As a result, It can be confirmed that the nanoporous structure is maintained.

Evaluation Example 3: Nitrogen adsorption experiment

Nitrogen adsorption experiments were carried out on the active materials of Comparative Example 1, Examples 1 to 4, Comparative Example 8 and Examples 7 to 10.

Nitrogen was adsorbed and desorbed in each of the powders in the experiment of nitrogen adsorption, and the specific surface area and pore volume of the material were calculated through the difference in the amount of adsorbed and desorbed nitrogen, and the pore size distribution was obtained. Specifically, the specific surface area of the pores was calculated from the N ₂ adsorption-desorption isotherm obtained from the nitrogen adsorption experiment using the BET (Brunauer-Emmett-Teller) method, and the total volume of the pores was calculated from the nitrogen adsorption / And the pore size distribution was shown using the BJH (Barrett-Joyner-Halenda) method. The results are shown in Tables 3 and 12 (the active material of Comparative Example 1 and Examples 1 to 4) 13 (active material of Comparative Example 8 and Examples 7 to 10)

Core component Specific surface area
(m2 / g) Pore volume
(mL / g) The first pore peak
(nm) 2nd workshop
peak
(nm) Comparative Example 1 SnO ₂ 112 0.25 2.9 15.6 Example 1 SnO ₂ 98 0.28 2.6 17.8 Example 2 SnO ₂ 107 0.28 2.5 17.9 Example 3 SnO ₂ 109 0.26 2.4 15.4 Example 4 SnO ₂ 97 0.25 2.4 15.4 Comparative Example 8 MoO ₂ 115 0.57 1.7 18.2 Example 7 MoO ₂ 118 0.46 1.7 17.6 Example 8 MoO ₂ 110 0.46 1.7 16.5 Example 9 MoO ₂ 91 0.47 . 16.5 Example 10 MoO ₂ 50 0.25 . 18.0

12 and 13, it can be seen that the active materials have a pore size distribution with two pore diameter peaks, and the active materials of Examples 1 to 4 and 7 to 10 are carbon It can be seen that the nanoporous structure is maintained after the thin film formation.

Evaluation Example 4: Evaluation of Raman spectrum

Raman spectra of the carbon thin films of the active materials of Comparative Example 2, Example 5, Example 6, Example 3, and Comparative Example 6 were evaluated, and the results are shown in Table 4 and Figs.

Comparative Example 2 Example 5 Example 6 Example 3 Comparative Example 6 D peak area / G peak area ratio (A _D / A _G ) 1.95 1.81 1.59 1.64 2.27 D peak intensity / G peak intensity (I _D / I _G ) 0.78 0.63 0.60 0.58 0.83

Of Table 4. Comparative Examples 2 and 6 from the A _D / A _G and I _D / I _G in Example 5,6 and 3 of the A _D / A _G and I _D / I _G smaller bar than in Example 5, 6 And 3 had better crystallinity than the carbon thin films of Comparative Examples 2 and 6.

Evaluation Example 5: Calorimetric analysis

The thermogravimetric analysis (TGA) was performed on the powders of Comparative Example 1 and Examples 1 to 4, and the results are shown in FIG. For thermogravimetric analysis, SDT2960 instrument from TA instruments was used. 16, mass reduction between 300 ° C and 700 ° C appears to correspond to a decrease in carbon mass (the mass decrease at 300 ° C or lower corresponds to the decrease of water and impurity mass, and the mass decrease at 700 ° C or higher corresponds to reduction It is assumed that the active material corresponds to the decrease in mass due to the phase change under high temperature in the atmosphere). From FIG. 16, it can be confirmed that the active material of Examples 1 to 4 contains the carbon thin film.

Evaluation Example 6: Evaluation of Conductivity

Pore-free spherical particles in the form of SnO ₂ core (Aldrich Corp., being SnO ₂ particles having an average particle size of less than about 100nm), Comparative Example 2, Example 5, Comparative Example 1, comparing the active material of Example 5 and Example 3 Were evaluated according to the pressure using the powder resistance measurement system LORESTA series (MCP-PD51). The results are shown in Figs. 17 and 18, respectively.

From FIG. 17, it can be confirmed that the conductivity of the active material of Example 5 is superior to that of the SnO ₂ core of the spherical particle type having no pores and the active material of Comparative Example 2.

18 that the conductivity of the active material of Example 3 is superior to that of the active materials of Comparative Examples 1 and 5. From this, it can be confirmed that the active material of Example 3 maintains the nanostructure of the core during the formation of the carbon thin film, and at the same time, improves the conductivity.

Evaluation Example 7: Evaluation of charge / discharge characteristics

(Cathode and lithium battery manufacturing)

15 mg of a carbon conductive agent (Super-P, Timcal Inc.) and 15 mg of a binder (polyamide / imide, PAI) were mixed with 15 mL of N-methylpyrrolidone (NMP) Were mixed together in agate mortar to prepare a slurry. The slurry was coated on a copper collector using a doctor blade to a thickness of about 50 탆, dried at room temperature for 2 hours, and dried again under vacuum at 200 캜 for 2 hours to prepare a negative electrode plate.

A 1.3 m LiPF ₆ electrolyte solution was prepared by dissolving the electrolyte solution in a mixed solvent of EC (ethylene carbonate) and DEC (diethyl carbonate) (3: 1), using a lithium metal as a counter electrode and a polypropylene separator (Cellgard 3510) 7 weight ratio) was used as an electrolyte to prepare a coin cell of CR-2016 standard.

Except that the active materials of Examples 1 to 4, Comparative Examples 8 and 7 to 10 were used in place of the active material of Comparative Example 1, respectively.

(Charge / discharge test)

The lithium battery including the active material of Comparative Example 1, Examples 1 to 4, Comparative Examples 8 and 7 to 10 was charged to a current of 100 mA per 1 g of the active material until the voltage reached 0.001 V (vs. Li) And discharged again at the same current until the voltage reached 2 V (vs. Li). Subsequently, charging and discharging were repeated 100 times in the same current and voltage sections.

19 shows the results of charging and discharging in the first cycle and the 50th cycle of the lithium battery including the active material of Comparative Example 1 and the lithium battery including the active material of Example 3. FIG. FIG. 21 shows the capacity retention rate of the lithium battery including the active materials of Comparative Examples 8 and 7 to 10, respectively. FIG. The capacity retention rate (%) in Figs. 20 and 21 was calculated by "(discharge capacity after each cycle / initial discharge capacity) x 100 ".

On the other hand, the cathode densities, capacity per gram, capacity per cc, initial efficiency, and 100 cycle life ([cycles of 100 cycles (Discharge capacity / initial discharge capacity) x 100 (%)) are shown in Table 5. However, the lithium battery including the active material of Comparative Example 1 in Table 5 shows the life of 50 cycles ([discharge capacity after 50 cycles / initial discharge capacity] x 100 (%)).

Anode active material Density (g / m ² ) Capacity per g
(mAh / g) Capacity per Cc
(mAh / CC) Initial efficiency
(%) 100 cycle life (%) Comparative Example 1 1.89 751.2 925.6 46.31 56.1
(50 cycle life) Example 1 1.94 743.3 1048.4 45.84 80.9 Example 2 2.10 693.1 1126.6 42.14 92.6 Example 3 2.09 662.5 973.2 42.07 95.4 Example 4 2.32 672.4 1092.9 40.72 103.9 Comparative Example 6 1.58 1207.28 1332.37 68.86 64.30 Example 7 1.63 1106.16 1264.48 69.51 82.50 Example 8 1.55 1064.27 1154.63 68.59 87.20 Example 9 1.52 1038.76 1102.79 70.07 87.87 Example 10 1.57 1014.84 1114.23 68.25 83.65

20 and 21 and Table 5 show that the lithium battery employing the negative electrode containing the active material of Examples 1 to 4 and Examples 7 to 10 has a superior capacity than the lithium battery employing the negative electrode containing the active material of Comparative Examples 1 and 8 And life span characteristics.

Claims (19)

A core containing at least one of a metal and a metal oxide capable of intercalating and deintercalating lithium ions; And a crystalline carbon thin film formed on at least a part of the core surface,
A nano-structured electrode active material. The method according to claim 1,
Wherein the electrode active material is in the form of particles, rods, wires or tubes. The method according to claim 1,
And a skeleton forming a wall between the pores and the pores. The method of claim 3,
And the pores are connected to each other to form a channel. The method according to claim 1,
Wherein the metal includes at least one of Sn, Fe, Co, Ni, Mn, Mn, Mo, Wherein the metal oxide comprises at least one of tin oxide, iron oxide, cobalt oxide, nickel oxide, zinc oxide, manganese oxide, molybdenum oxide and bismuth oxide. The method according to claim 1,
Wherein the core comprises at least one of SnO ₂ and MoO ₂ . The method according to claim 1,
Wherein the crystalline carbon thin film has a thickness of 2 nm or less. The method according to claim 1,
When the intensity of the D peak present at the wavenumber of 1360 10 cm ^-1 in the Raman spectrum of the crystalline carbon thin film is I _D and the intensity of the G peak present at the wavenumber of 1580 10 cm ^-1 is I _G , I _D / I _G is 0.7 or less. The method according to claim 1,
The powder resistance of from ^{31.83 Mpa 2.0 x 10 -5 S /} cm to 1.0 x 10 ^-2 S / cm of the electrode active material. The method according to claim 1,
A specific surface area of the core A and La, La when the mass of the carbon thin film B, B / A is ^{7.69 x 10 -3 g 2 / m} 2 or less, the electrode active material. The method according to claim 1,
And an electrode active material having a specific surface area of 50 m ² / g to 250 m ² / g. An electrode comprising the electrode active material of any one of claims 1 to 11 A lithium battery including the electrode of claim 12. 14. The method of claim 13,
Wherein the electrode is a negative electrode. A core containing at least one of metal and metal oxides capable of intercalating and deintercalating lithium ions, a carbonaceous precursor represented by Chemical Formula 1, and a solvent are mixed to prepare a carbon-based moiety represented by the following Chemical Formula 2 ; And
The method of any one of claims 1 to 11, further comprising the step of heat-treating the core formed with the carbon-based moiety in an inert atmosphere to convert the carbon-based moiety into a crystalline carbon thin film.
&Lt; Formula 1 >< EMI ID =

Among the above general formulas (1) and (2)
Ring A is a substituted or unsubstituted C ₅ -C ₃₀ aromatic ring or a substituted or unsubstituted C ₂ -C ₃₀ heteroaromatic ring;
a and b are each independently an integer of 1 to 5;
* Is a binding site with the core surface. 16. The method of claim 15,
The ring A may be substituted or unsubstituted benzene, substituted or unsubstituted pentarenes, substituted or unsubstituted indenes, substituted or unsubstituted naphthalenes, substituted or unsubstituted azulenes, substituted or unsubstituted heptarenes, substituted Substituted or unsubstituted phenanthrene, substituted or unsubstituted anthracene, substituted or unsubstituted anthracene, substituted or unsubstituted fluorene, substituted or unsubstituted phenanthrene, substituted or unsubstituted anthracene, substituted or unsubstituted anthracene, Substituted or unsubstituted pyrene, substituted or unsubstituted pyrene, substituted or unsubstituted pyrene, substituted or unsubstituted pyrene, substituted or unsubstituted pyrene, substituted or unsubstituted pyrene, substituted or unsubstituted pyrene, substituted or unsubstituted pyrene, substituted or unsubstituted pyrene, Substituted or unsubstituted pyrazole, substituted or unsubstituted pyrazole, substituted or unsubstituted pyrazole, substituted or unsubstituted pyrazole, substituted or unsubstituted pyrazole, substituted or unsubstituted pyrazole, substituted or unsubstituted imidazole, substituted or unsubstituted imidazole , Substituted or unsubstituted imidazopyridine, substituted or unsubstituted imidazopyrimidine, substituted or unsubstituted pyridine, substituted or unsubstituted pyrazine, substituted or unsubstituted pyrimidine, substituted or unsubstituted pyridazine , A substituted or unsubstituted indole, a substituted or unsubstituted purine, a substituted or unsubstituted quinoline, a substituted or unsubstituted phthalazine, a substituted or unsubstituted indole, a substituted or unsubstituted naphthyridine, Substituted or unsubstituted thienolines, substituted or unsubstituted indazoles, substituted or unsubstituted carbazoles, substituted or unsubstituted phenazines, substituted or unsubstituted phenanthridines, substituted or unsubstituted quinazolines, Triazine, substituted or unsubstituted phenanthroline, or substituted or unsubstituted quinoxaline. 16. The method of claim 15,
Wherein ring A is selected from the group consisting of benzene, naphthalene, phenalene, phenanthrene, anthracene, triphenylene, pyrene, chrysene, naphthacene, picene, perylene ), Pentaphene, hexacene, pyridine, pyrazine, pyrimidine, pyridazine, quinoline, phthalazine, quinoxaline, quinazoline, cinnoline, phenanthridine, phenanthroline or phenazine , and a and b are 1 or 2. 16. The method of claim 15,
Wherein the step of forming the carbon-based moiety on at least a part of the surface of the core is performed at a temperature of 100 ° C to 500 ° C for 1 hour to promote the dehydration reaction between the hydroxyl group of the core surface and the hydroxyl group of the carbon- Further comprising a heat treatment step in a range of 5 to 5 hours. 16. The method of claim 15,
Wherein the heat treatment of the core in which the carbon-based moiety is formed is performed at a temperature of 300 ° C to 600 ° C for 1 hour to 5 hours.

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