TW201345017A - Composite powder for making electrode and electrochemical device using the same - Google Patents

Abstract

The present invention relates to a composite powder for making an electrode, which includes: active material particles; and glass material particles, which are smaller than the active material particles in diameter and dispersed on the surface of the active material particles and have a glass transition temperature from 150 DEG C to 400 DEG C. The composite powder of the present invention can ensure the safety of electrochemical devices. In addition, the present invention further provides an electrochemical device using the above-mentioned composite powder.

Description

Composite powder for making electrodes and electrochemical device using same

The present invention relates to a composite powder for producing an electrode and an electrochemical device using the same, and more particularly to a composite powder which can improve battery safety and an electrochemical device using the same.

Nowadays, with the development of various portable electronic devices and the increasing demand for mobile devices, the attention paid to energy storage technologies and portable energy sources has also increased. At present, the portable energy source widely used is a secondary battery, and since the lithium ion secondary battery has the advantages of high energy density, high capacitance density, good cycle charge and discharge characteristics, and no memory effect, the secondary battery is further Lithium ion secondary batteries are most widely used.

However, lithium ion secondary batteries may have safety problems such as fire or even explosion due to abnormally high temperature of the battery. The internal short circuit of the battery is often the main cause of the sudden rise of the battery temperature, and the cause of the internal short circuit of the battery includes the battery being damaged by external force. Or an internal short circuit caused by overcharging the battery. If the battery temperature continues to rise and reaches a certain level, the positive electrode material of the battery will begin to decompose to generate oxygen and radiate heat violently, so that the instantaneous temperature of the battery rises sharply and a large amount of gas is ejected, which may cause the battery to ignite and explode.

In order to solve the above battery safety problem, a related research team has proposed a STOBA (Self Terminated Oligomers with hyper-Branched Architecture) polymer electrolyte, which can form a protective film when the battery temperature rises to block the ion channel and terminate the electrification. Learning to prevent the battery from thermal runaway (Thermal Runaway) phenomenon to improve battery safety. However, when such a polymer electrolyte is applied to a large-sized battery, since it cannot form a comprehensive protective film on the surface of a large-area electrode plate, such a polymer electrolyte cannot effectively solve the safety of a large-sized, high-energy battery. problem.

In view of this, there is an urgent need to develop a related technology that can effectively solve the problem of battery safety, so as to facilitate the development of secondary batteries in the direction of large-scale and high-energy, so that secondary batteries can be widely used in various fields, such as New energy vehicles, large energy storage equipment, etc.

The object of the present invention is to provide a composite powder for forming an electrode, which can effectively improve battery safety, and has the advantages of simple preparation method, low production cost, and favorable mass production.

In order to achieve the above object, the present invention provides a composite powder for forming an electrode, comprising: active material particles; and glass material particles having a particle diameter smaller than that of the active material particles and distributed on the surface of the active material particles, The glass transition temperature (Tg) of the glass material particles ranges from 150 ° C to 400 ° C. For example, the glass transition temperature (Tg) of the glass material particles in the embodiment of the present invention ranges from about 250 ° C to 400 ° C. Further, the glass softening temperature (Td) of the glass material particles may range from about 250 ° C to 500 ° C. For example, the glass softening temperature (Td) of the glass material particles in the embodiment of the present invention ranges from about 300 ° C to 450 ° C.

Since the ions can still penetrate the gap between the glass material particles to reach the active material for electrochemical reaction, the glass material distributed on the surface of the active material does not block the electrochemical reaction. However, when the battery using the composite powder to make the electrode undergoes a superheat reaction, the hot-cold low-temperature glass material particles can self-react to produce shrinkage fusion and bonding, and immediately form a protective film of 1 to 5 μm on the surface of the active material particle to reach the blocking ion. Flow and stop the effect of the electrochemical reaction to avoid battery explosion. Accordingly, compared with the above STOBA technology, the composite powder of the present invention can ensure the safety of the battery even when applied to a battery having a large capacity and a large number of hours.

The composite powder of the present invention can be used for producing a positive electrode, that is, a low-temperature glass material particle can be distributed on the surface of the positive electrode active material particle to form a composite powder for producing a positive electrode. For example, the positive electrode of the lithium ion secondary battery can be fabricated by using the above composite powder, and accordingly, the composite powder can use a lithium-containing metal composite oxide as an active material, and the active material particles can also selectively contain an appropriate amount. Conductive material to improve the conductivity of the electrode material. Here, the lithium-containing metal composite oxide and the conductive material are not particularly limited, and may be any suitable lithium-containing metal composite oxide and a conductive material. For example, the lithium-containing metal composite oxide may be lithium iron phosphate (LiFePO ₄ ), lithium nickel cobalt manganese oxide (LiNiCoMnO ₂ ), lithium manganese oxide (LiMnO ₂ ), lithium nickel oxide (LiNiO ₂ ), lithium cobalt. oxide (LiCoO _2), lithium nickel cobalt aluminum oxide (LiNiCoAlO _2), lithium nickel cobalt manganese oxide (LiNiMnO ₂₎ or lithium nickel cobalt oxide (LiNiCoO ₂₎ and the like, and the conductive material may be a carbon material.

In the present invention, the glass material particles are not particularly limited, and may be any glass material particles having a glass transition temperature ranging from about 150 ° C to 400 ° C. For example, the glass material particles may use ZnO-P ₂ O ₅ -B ₂ O ₃ , ZnO-P ₂ O ₅ -Nb ₂ O ₅ , SnO-MgO-P ₂ O ₅ , SnO-MnO-P ₂ O ₅ , SnO-ZnO-P ₂ O ₅ , Bi ₂ O ₃ -ZnO-B ₂ O ₃ , Li ₂ O-ZnO-SiO ₂ , BaO-ZnO-B ₂ O ₃ , Li ₂ O-Al ₂ O ₃ - SiO ₂ , Tl ₂ O ₃ -V ₂ O ₃ -P ₂ O ₅ , V ₂ O ₅ -ZnO-BaO-TeO ₂ , V ₂ O ₅ -ZnO-BaO-P ₂ O ₅ , V ₂ O ₅ -ZnO -BaO, PbO-B ₂ O ₃ , P ₂ O ₅ -Nb ₂ O ₅ -Al ₂ O ₃ -Bi ₂ O ₃ -B ₂ O ₃ , ZnO-P ₂ O ₅ -Nb ₂ O ₃ -Al ₂ O ₃ , PbO-B ₂ O ₃ -SiO ₂ , Bi ₂ O ₃ -B ₂ O ₃ -SiO ₂ , SiO ₂ -P ₂ O ₅ -SnO, SiO ₂ -P ₂ O ₅ -SnO-ZnO or a combination thereof Materials, but are not limited to this. Preferably, the glass material particles are conductive glass material particles such as Li ₂ O-Al ₂ O ₃ -SiO ₂ , SnO-ZnO-P ₂ O ₅ or the like. Accordingly, the use of the electrode of the composite powder eliminates the need to add additional conductive material.

The composite powder of the present invention may have an average particle diameter (D50) of about 0.5 μm to 50 μm and a D90 of about 1 μm to 100 μm, wherein the average particle diameter (D50) of the glass material particles may be about 0.1 μm to 20 μm. And D90 may be about 0.2 μm to 40 μm, and the average particle diameter (D50) of the active material particles may be about 0.3 μm to 30 μm and D90 may be about 0.6 μm to 60 μm. For example, in an embodiment of the present invention, the D50 of the active material particles is about 3 μm to 10 μm, and the D90 is about 6 μm to 22 μm; the D50 of the glass material particles is about 1 μm to 2 μm, and the D90 is about 2 Μm to 4 μm; the composite powder has a D50 of about 5 μm to 12 μm and a D90 of about 8 μm to 26 μm. Further, the thickness of the particle layer formed on the surface of the active material particles by the glass material particles is preferably from 1 to 5 μm so as to prevent the glass material layer from being too thick to affect the ion permeability. Furthermore, the weight ratio of the active material particles to the glass material particles may be about 10:1 to 25:1. For example, in the embodiment of the present invention, the weight ratio of the active material particles to the glass material particles is about 10:1 to 20:1. .

The composite powder of the present invention can be obtained by mixing an active material and a glass material and then performing a drying step. Here, the ball mill, the bead mill, or other equipment capable of grinding and dispersing may be used for grinding and stirring, or a high-speed mixer, an emulsifier, a low-speed mixer, or the like may be used for stirring and dispersing to uniformly mix the active material and the glass material. The glass material can be uniformly dispersed on the surface of the active material. In addition, the drying step can be carried out by spray drying, and the particle size distribution of the composite powder can be controlled simultaneously while drying the powder. Accordingly, the composite powder of the present invention has the advantages of simple process, low production cost, and suitability for mass production.

In the present invention, the source of the active material and the glass material is not particularly limited, that is, the active material and the glass material obtained by any known method can be used. For example, the phosphoric acid-containing precursor, the lithium-containing precursor, the metal source, and the carbon source may be ground at room temperature, and then the granular mixture is prepared by a spray granulation process, and finally the granular mixture is sintered. A porous lithium metal phosphate (such as lithium iron phosphate) active material coated with a carbon material is prepared. In addition, the glass material can be obtained by mixing the precursor, followed by a melting step, and then pouring into water to quench to form glass cullet and then grinding.

The present invention further provides an electrode using the above composite powder, comprising: an electrode substrate (such as a metal sheet or a metal mesh); and an electrode coating coated on the electrode substrate, wherein the electrode coating comprises The above composite powder may optionally be added with an appropriate amount of a binder or a conductive material.

The present invention also provides a method for preparing the above electrode, comprising the steps of: coating an electrode slurry comprising the above composite powder on an electrode substrate; and drying the electrode slurry to form on the electrode substrate Electrode coating. Here, the electrode slurry may optionally be added with an appropriate amount of a binder or a conductive material.

The present invention further provides an electrochemical device using the above composite powder, comprising: a positive electrode; a negative electrode; a separator separating the positive electrode and the negative electrode; and an electrolyte forming the positive electrode and the negative electrode The ion channel, wherein at least one of the positive electrode and the negative electrode uses a composite powder comprising active material particles and glass material particles, the particle diameter of the glass material particles is smaller than the particle diameter of the active material particles, and is distributed in the active material The surface of the particles, and the glass transition temperature of the glass material particles ranges from 150 ° C to 400 ° C. Here, the electrochemical device may be a lithium ion secondary battery, and the composite powder may be used in a positive electrode, whereby the active material in the composite powder may be a lithium-containing metal composite oxide.

In summary, the composite powder of the present invention can form a 1 to 5 μm film on the surface of the active material by the self-shrinking fusion and bonding reaction of the low temperature glass material when the temperature of the battery rises, thereby blocking the ion flow and The effect of the electrochemical reaction is terminated to avoid explosion of the battery, thereby effectively improving the safety of the electrochemical device (such as a lithium ion secondary battery). In addition, the composite powder of the present invention has the advantages of simple process, low production cost and suitable for mass production, and thus has considerable market competitiveness.

The embodiments of the present invention are described below by way of specific specific examples, and those skilled in the art can readily appreciate the other advantages and advantages of the present invention. The present invention may be embodied or applied in various other specific embodiments. The various details of the present invention can be applied to various aspects and applications, and various modifications and changes can be made without departing from the spirit of the invention.

Preparation Example 1

The positive active material LiFePO ₄ and the low temperature glass material SnO-P ₂ O ₅ -MgO (% of mole: 65% SnO + 32.5% P ₂ O ₅ + 2.5% MgO, Tg: 335 ° C, Td: 400 ° C) according to 10 The weight ratio of 1 is mixed, and the mixture is stirred or stirred at room temperature to obtain a mixture in which the low-temperature glass material is uniformly dispersed on the surface of the positive electrode active material.

Next, the mixture is rapidly dried by a spray drying method, and the particle size distribution is controlled to obtain a positive electrode composite powder of the preparation example 1 of the present invention (D50 of about 5 μm, D90 of about 10 μm), wherein the positive electrode composite powder system is composed of an active material. The particles (D50 of about 4 μm, D90 of about 8 μm) and low-temperature glass material particles (D50 of about 1 μm, D90 of about 2 μm) are composed, and the low-temperature glass material particles are distributed on the surface of the active material particles.

Preparation Example 2-5

The preparation method of Preparation Example 2-5 of the present invention is substantially the same as that described in Preparation Example 1, except that the active material (component A) and the low-temperature glass material (component B) used in Preparation Example 2-5 of the present invention are different. The weight ratio (A: B), the active material particle diameter (A particle diameter), the glass material particle diameter (B particle diameter), and the positive electrode composite powder particle diameter (C particle diameter) are shown in Table 1 below.

"Table 1"

Preparation 6-7

The preparation method of Preparation Examples 6-7 of the present invention is substantially the same as that described in Preparation Example 1, except that the active material (component A) and the low-temperature glass material (component B) used in Preparation Examples 6-7 of the present invention are different. The weight ratio (A: B), the active material particle diameter (A particle diameter), the glass material particle diameter (B particle diameter), and the positive electrode composite powder particle diameter (C particle diameter) are shown in Table 2 below.

Preparation Examples 8-9

The preparation method of Preparation Examples 8-9 of the present invention is substantially the same as that described in Preparation Example 1, except that the active material (component A) and the low-temperature glass material (component B) used in Preparation Examples 8-9 of the present invention are different. The weight ratio (A: B), the active material particle diameter (A particle diameter), the glass material particle diameter (B particle diameter), and the positive electrode composite powder particle diameter (C particle diameter) are shown in Table 3 below.

Preparation 10-13

The preparation method of Preparation Examples 10-13 of the present invention is substantially the same as that described in Preparation Example 1, except that the active material (component A) and the low-temperature glass material (component B) used in Preparation Examples 10-13 of the present invention are different. The weight ratio (A: B), the active material particle diameter (A particle diameter), the glass material particle diameter (B particle diameter), and the positive electrode composite powder particle diameter (C particle diameter) are shown in Table 4 below.

Preparation 14-24

The preparation method of Preparation Examples 14-24 of the present invention is substantially the same as that described in Preparation Example 1, except that the low temperature glass materials used in Preparation Examples 14-24 of the present invention are respectively Tl ₂ O ₃ -V ₂ O ₃ -P. ₂ O ₅ , V ₂ O ₅ -ZnO-BaO-TeO ₂ , V ₂ O ₅ -ZnO-BaO-P ₂ O ₅ , V ₂ O ₅ -ZnO-BaO, PbO-B ₂ O ₃ , P ₂ O ₅ -Nb ₂ O ₅ -Al ₂ O ₃ -Bi ₂ O ₃ -B ₂ O ₃ , ZnO-P ₂ O ₅ -Nb ₂ O ₃ -Al ₂ O ₃ , PbO-B ₂ O ₃ -SiO ₂ , Bi ₂ O ₃ -B ₂ O ₃ -SiO ₂ , SiO ₂ -P ₂ O ₅ -SnO, SiO ₂ -P ₂ O ₅ -SnO-ZnO.

Example

The composite powder obtained by drying in Preparation Examples 1 to 24 can be directly used to form a positive electrode, or the dried composite powder can be further dried by heating at 100 ° C to 150 ° C to reduce the water content of the powder to less than 1000 ppm. After that, a positive electrode is fabricated, and then a suitable negative electrode, separator, and electrolyte are used to assemble a lithium ion secondary battery. Since the electrodes and the battery are manufactured in a manner well known to those skilled in the art, they are not described herein.

1 is a schematic diagram of a lithium ion secondary battery, comprising: a housing 1; an electrolyte 5 housed in the housing 1; and a positive electrode 2, a negative electrode 3 interposed in the electrolyte 5, and isolated The membrane 4, wherein the separator 4 separates the positive electrode 2 and the negative electrode 3, and the electrolyte 5 forms a lithium ion channel between the positive electrode 2 and the negative electrode 3.

In the lithium ion secondary battery of the present embodiment, the positive electrode 2 is a positive electrode composite powder obtained by the above Preparation Examples 1 to 24, which comprises active material particles and low-temperature glass material particles distributed on the surface of the active material particles. Accordingly, when the battery is overheated, the low temperature glass material in heat can self-react to produce shrinkage fusion and bonding, thereby forming a film of 1 to 5 μm on the surface of the active material, effectively blocking the ion flow, terminating the electrochemical reaction, and avoiding The battery explodes to improve the safety of the battery.

The above-mentioned preparation examples are only for the convenience of description, and the scope of the claims is based on the scope of the patent application, and is not limited to the above preparation examples.

1. . . case

2. . . Positive electrode

3. . . Negative electrode

4. . . Isolation film

5. . . Electrolyte

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a lithium ion secondary battery of the present invention.

1. . . case

2. . . Positive electrode

3. . . Negative electrode

4. . . Isolation film

5. . . Electrolyte

Claims (20)

A composite powder for forming an electrode, comprising: active material particles; and glass material particles having a particle diameter smaller than a particle diameter of the active material particles and distributed on a surface of the active material particles, wherein the glass of the glass material particles The transfer temperature ranges from 150 ° C to 400 ° C. The composite powder according to claim 1, wherein the glass material particles are electrically conductive. The composite powder according to claim 1, wherein the glass material particles are ZnO-P ₂ O ₅ -B ₂ O ₃ , ZnO-P ₂ O ₅ -Nb ₂ O ₅ , SnO-MgO- P ₂ O ₅ , SnO-MnO-P ₂ O ₅ , SnO-ZnO-P ₂ O ₅ , Bi ₂ O ₃ -ZnO-B ₂ O ₃ , Li ₂ O-ZnO-SiO ₂ , BaO-ZnO-B ₂ O ₃ , Li ₂ O-Al ₂ O ₃ -SiO ₂ , Tl ₂ O ₃ -V ₂ O ₃ -P ₂ O ₅ , V ₂ O ₅ -ZnO-BaO-TeO ₂ , V ₂ O ₅ -ZnO-BaO -P ₂ O ₅ , V ₂ O ₅ -ZnO-BaO, PbO-B ₂ O ₃ , P ₂ O ₅ -Nb ₂ O ₅ -Al ₂ O ₃ -Bi ₂ O ₃ -B ₂ O ₃ ,ZnO-P ₂ O ₅ -Nb ₂ O ₃ -Al ₂ O ₃ , PbO-B ₂ O ₃ -SiO ₂ , Bi ₂ O ₃ -B ₂ O ₃ -SiO ₂ , SiO ₂ -P ₂ O ₅ -SnO, SiO ₂ - P ₂ O ₅ -SnO-ZnO or a combination thereof is used as the material. The composite powder according to claim 1, wherein the average particle diameter (D50) is from 0.5 μm to 50 μm. The composite powder according to claim 1, wherein the glass material particles have an average particle diameter (D50) of from 0.1 μm to 20 μm. The composite powder according to claim 1, wherein the active material particles have an average particle diameter (D50) of from 0.3 μm to 30 μm. The composite powder according to claim 1, wherein the weight ratio of the active material particles to the glass material particles is from 10:1 to 25:1. The composite powder according to claim 1, which is used for a lithium ion secondary battery. The composite powder according to claim 1, wherein the active material particles are a positive electrode active material particle. The composite powder according to claim 9, wherein the positive electrode active material particles are a lithium-containing metal composite oxide. An electrochemical device comprising: a positive electrode; a negative electrode; an isolating film separating the positive electrode and the negative electrode; and an electrolyte forming an ion channel between the positive electrode and the negative electrode, wherein At least one of the positive electrode and the negative electrode uses a composite powder comprising active material particles and glass material particles, the particle diameter of the glass material particles being smaller than the particle diameter of the active material particles, and distributed in the active material particles The surface, and the glass transition temperature of the glass material particles ranges from 150 ° C to 400 ° C. The electrochemical device according to claim 11, wherein the glass material particles are electrically conductive. The electrochemical device according to claim 11, wherein the glass material particles are ZnO-P ₂ O ₅ -B ₂ O ₃ , ZnO-P ₂ O ₅ -Nb ₂ O ₅ , SnO-MgO- P ₂ O ₅ , SnO-MnO-P ₂ O ₅ , SnO-ZnO-P ₂ O ₅ , Bi ₂ O ₃ -ZnO-B ₂ O ₃ , Li ₂ O-ZnO-SiO ₂ , BaO-ZnO-B ₂ O ₃ , Li ₂ O-Al ₂ O ₃ -SiO ₂ , Tl ₂ O ₃ -V ₂ O ₃ -P ₂ O ₅ , V ₂ O ₅ -ZnO-BaO-TeO ₂ , V ₂ O ₅ -ZnO-BaO -P ₂ O ₅ , V ₂ O ₅ -ZnO-BaO, PbO-B ₂ O ₃ , P ₂ O ₅ -Nb ₂ O ₅ -Al ₂ O ₃ -Bi ₂ O ₃ -B ₂ O ₃ ,ZnO-P ₂ O ₅ -Nb ₂ O ₃ -Al ₂ O ₃ , PbO-B ₂ O ₃ -SiO ₂ , Bi ₂ O ₃ -B ₂ O ₃ -SiO ₂ , SiO ₂ -P ₂ O ₅ -SnO, SiO ₂ - P ₂ O ₅ -SnO-ZnO or a combination thereof is used as the material. The electrochemical device according to claim 11, wherein the electrode composite powder has an average particle diameter (D50) of from 0.5 μm to 50 μm. The electrochemical device according to claim 11, wherein the glass material particles have an average particle diameter (D50) of from 0.1 μm to 20 μm. The electrochemical device according to claim 11, wherein the active material particles have an average particle diameter (D50) of from 0.3 μm to 30 μm. The electrode material according to claim 11, wherein the weight ratio of the active material particles to the glass material particles is from 10:1 to 25:1. The electrochemical device according to claim 11, which is a lithium ion secondary battery. The electrode material according to claim 11, wherein the positive electrode is a composite powder comprising the active material particles and the glass material particles. The electrode material according to claim 19, wherein the active material particles are a lithium-containing metal composite oxide.