TWI578602B - Method for manufacturing carbon fiber anode material for lithium ion battery - Google Patents

Description

Method for manufacturing carbon ruthenium anode material of lithium ion battery

The invention relates to a method for manufacturing a negative electrode material for a lithium ion battery, and more particularly to a method for manufacturing a carbon crucible negative electrode material for a lithium ion battery.

Lithium-ion battery is an electrical device, which has many advantages, such as convenient portability, high energy density, and no noise and no exhaust emission. It can be widely used in many fields, from cell phone batteries to batteries for electric vehicles. Lithium Ion Battery. Referring to Fig. 4, it is a schematic diagram of discharge of a conventional lithium ion battery of the prior art. As shown in Fig. 4, a lithium ion battery is commercially available from the following four components: an electrode (positive and negative), an electrolyte, a separator, and a can. Wherein, the leftmost side is the anode (Anode) pole piece 10, on which the negative electrode material particles 20 are coated or sprayed; the middle is a separator film 60, which allows the lithium ions 50 to pass back and forth in both directions during charging and discharging: and the rightmost side is the positive electrode (Cathode) pole piece 30 on which positive electrode material particles 40 are coated. In the charging process, the lithium ion 50 moves from the positive electrode to the negative electrode; and during the discharging process, the lithium ion 50 moves from the negative electrode to the positive electrode. The composition, characteristics, and functions of the electrode, electrolyte, separator, and tank are described below:

(1) The electrode is composed of a conductive electrode sheet and an active material thereon, and the active material can undergo a redox reaction on the conductive electrode sheet. A redox reaction occurs between the negative electrode (anode) and the positive electrode (cathode) to convert chemical energy into electrical energy. Generally, a cathode material of a general lithium ion battery includes: materials such as LiCoO ₂ , LiNiO ₂ , LiMn ₂ O _{4 ,} and LiCo _x Ni _1-x O ₂ ; and a negative electrode material includes: amorphous carbon, graphite material, carbon coated graphite material, MCMB, hard carbon, etc.

(2) The electrolyte is placed between the negative electrode (anode) and the positive electrode (cathode) in the battery, and the electrons generated by the redox reaction are sent to the electric device through the circuit connected outside the battery; and the charged ions are generated. During the charging process, the electrolyte is transferred from the positive electrode to the negative electrode via the separator; and during the discharge, in the opposite manner.

(3) The isolation film is disposed between the two electrodes to isolate the positive electrode from the negative electrode to avoid direct contact between the two electrodes and cause internal short circuit of the battery. However, the separator allows charged ions to pass through to form a via.

(4) The tank body is the outer casing of the battery to protect its internal structure, and has good mechanical, heat, vibration, and corrosion resistance, and can be cylindrical, square, button type, and the like.

Regarding the prior art, the chemical formula of the redox reaction of the negative electrode of the lithium ion battery and the positive electrode (refer to Table 1). Among them, the negative electrode tab is usually made of copper foil, and the positive (cathode) conductive plate is usually made of aluminum foil.

In the current lithium ion (Li ⁺ ) battery manufacturing technology, the selection criteria of the anode material mainly considers the capacitance thereof. The theoretical capacity of graphite is 372 mAh/g, which is the main material of the negative electrode. In actual manufacturing, the electrical capacity that can be achieved is 360 mAh/g. Moreover, since the theoretical capacitance of bismuth is 4200 mAh/g, 2~15% of ruthenium is usually added to the graphite material when manufacturing the negative electrode material, so that the capacitance of the mixed material can be increased to 400-600 mAh/g to strengthen lithium. The effect of charging and discharging the ion battery. However, the tantalum material easily swells during charging and discharging, and thus peels off, resulting in deterioration of charging and discharging efficiency. Generally, the efficiency standard for charging and discharging a negative electrode material of a lithium ion battery is to achieve an 80% charge and discharge efficiency after 500 charge and discharge cycles. However, the above-mentioned graphite and ruthenium mixed negative electrode material undergoes only 100 cycles of charge and discharge cycles due to expansion, peeling, and detachment of the ruthenium, that is, the charge and discharge efficiency of deterioration to 80% or less.

Therefore, there are still many defects and shortcomings in the manufacture and performance of the anode materials of lithium ion batteries, and there is a need for further improvement.

In order to solve the above-mentioned shortcomings and disadvantages of the prior art, the present invention provides a method for manufacturing a carbon nanotube anode material for a lithium ion battery, which is firstly mixed and granulated by ruthenium, graphite, and pitch powder, and then in the formed nuclear sphere, The graphite fine powder asphalt forms an outer layer (Shell), and the core of the cerium and the graphite particles is surrounded by the core to avoid the swelling phenomenon of the cerium particles, and the charging and discharging efficiency of the lithium ion battery is degraded to overcome the conventional technology. The above is missing and a good charge and discharge efficiency is achieved.

In order to achieve the above object of the present invention, the present invention provides a method for producing a carbon nanotube anode material for a lithium ion battery, comprising the steps of: first, placing a powder of ruthenium, graphite, and pitch into a granulator, adding water, and coupling The agent and the CMC binder are mixed and stirred in the granulator, and granulated at a high speed by mixing at room temperature. A viscous mixture is prepared through this step.

Next, the viscous mixture was placed in a dryer and dried at a process temperature of 300 to 500 ° C for 10 hours to make it into a nuclear sphere shape. Inside the nuclear sphere, the ruthenium particles and the graphite particles are uniformly mixed with each other, and the asphalt forms an outer asphalt layer surrounding the nucleus. The sphere formed by this has an average particle diameter (D50) of about 6 to 9 μm.

Then, the 6~9 μm nuclear sphere-shaped particle powder (70-80%) prepared in the above step is placed in a high-speed mixing granulator, and 1 to 3 μm of pitch (5 to 10%) is added, and 3-5 μm of graphite is finely mixed. The powder (15~20%) is put together, and water, a coupling agent and a CMC binder are mixed and stirred in the high-speed mixing granulator, and high-speed mixing granulation is carried out at room temperature. The process time is from 30 minutes to 1 hour to make a viscous mixture.

Subsequently, the viscous mixture is placed in a heat treatment carbonization furnace for carbonization, and is subjected to high temperature treatment at 850 to 900 ° C for 10 to 12 hours to heat the viscous mixture into spherical shape particle powder. Wherein, the inside of the sphere is a nucleus (Core) of bismuth and graphite particles, and a graphite layer (Shell) formed by carbonization of the graphite fine powder and the asphalt to surround the nucleus of the nucleus to suppress ruthenium The particles expand during charging and discharging of the battery. The sphere formed by this has an average particle diameter (D50) of about 16-18 μm.

The purpose of forming the first layer of asphalt in the above process is to combine the ruthenium particles with the graphite particles to form a core sphere; and the purpose of forming the second asphalt layer is to form an elastic graphite layer with the graphite fine powder (Shell) ), used to coat, protect, and inhibit the expansion, peeling, and shedding of cerium particles to improve the charging and discharging efficiency of lithium ion batteries.

The carbon nanotube anode material of the lithium ion battery prepared by the method of the invention can avoid the expansion, peeling and falling off of the crucible in the anode material after the long-term charging and discharging process, so as to avoid degradation of the charging and discharging efficiency.

10‧‧‧Negative pole piece

20‧‧‧Anode material particles

30‧‧‧ positive pole piece

40‧‧‧positive material particles

50‧‧‧Lithium ion

60‧‧‧Separator

P‧‧‧ asphalt layer

G‧‧‧graphite particles

Si‧‧‧矽 particles

1 is a schematic view of a nuclear particle powder of a carbon ion anode material of a lithium ion battery according to a first process of an embodiment of the method of the present invention; and FIG. 2 is a second process of an embodiment of the method according to the present invention. A schematic diagram of a spherical particle powder of a carbon-nano anode material for a lithium ion battery; FIG. 3 is a flow chart showing the steps of a method for producing a carbon-ruthenium anode material of a lithium ion battery according to the present invention; and FIG. 4 is a discharge of a lithium ion battery of the prior art. Process overview.

In order to facilitate the review of the contents of the present invention and the effects that can be achieved by the reviewing committee, the specific embodiments are listed with reference to the drawings, and the details are as follows:

First process

In order to solve the above-mentioned deficiencies of the prior art, the present invention provides a method for producing a carbon-n-tube anode material for a lithium ion battery, which comprises mixing and granulating a powder of cerium particles Si, graphite particles G, and pitch particles P to form mixed particles. In the powder, the outermost asphalt layer P is formed of pitch, and the cerium particles Si and the graphite particles G are mixed and surrounded therein to form a core sphere. This manufacturing method is described in detail as follows:

Referring to Fig. 3, there is shown a flow chart of the steps of the method for producing a carbon nanotube anode material for a lithium ion battery according to the present invention. As shown in FIG. 3, the manufacturing method of the present invention comprises the following steps: First, the powder of cerium, graphite, and pitch particles is placed in a granulator, and water, a coupling agent, and a CMC binder are added thereto. In the granulator (step 310). Second, use the granulator to The mixture was stirred and mixed therein, and subjected to high-speed mixing granulation. Among them, the particle diameters of Silicon, Graphite, and Pitch are: 1 to 2 μm (矽), 3 to 5 μm (graphite), and 1 to 3 μm (asphalt), and the weight percentage of the powder. Each is: 3~6% (矽), 91~82% (graphite), 6~12% (asphalt). The process temperature is room temperature and the process time is from 30 minutes to 1 hour, and a viscous mixture is formed through the process (step 320).

Then, the viscous mixture was placed in a dryer and heated at a process temperature of 300 to 500 ° C for 10 hours to form a nuclear sphere shape as shown in Fig. 1. Wherein, inside the nuclear sphere, the cerium particles Si and the graphite particles G are uniformly mixed with each other, and the asphalt forms an outer asphalt layer P surrounding the nucleus. The sphere formed by this has an average particle diameter (D50) of about 6 to 9 μm (step 330).

Second process

Subsequently, the 6~9 μm nuclear sphere-shaped particle powder (70-80%) prepared in the above step was placed in a high-speed mixing granulator, and 1 to 3 μm of pitch (5 to 10%) and 3 to 5 μm of graphite fine powder ( 15~20%) are put together, and water and coupling agent and CMC binder are added to the high speed mixing granulator (step 340). Then, the above mixture was mixed and stirred at room temperature using a granulator for a process time of 30 minutes to 1 hour to prepare a viscous mixture (step 350).

Finally, the liquid slurry mixture is placed in a heat treatment carbonization furnace for carbonization, carbonized at a high temperature for 10 to 12 hours, and the carbonization temperature is 850 to 900 ° C, so that the viscous mixture is heated into a spherical shape particle powder, as shown in FIG. 2 Shown (step 360). Wherein, the inside of the sphere is a nucleus of bismuth and graphite particles, and after the graphite fine powder and the asphalt are carbonized, an elastic graphite layer is formed to surround the outer layer of the nucleus. During charge and discharge, the core volume of the core expands three times, but because the fine-grained graphite powder outside the core forms a shell with the asphalt, A layer of buffering effect, which surrounds the outermost layer of the sphere, can inhibit the expansion of the cerium (Si) particles during charging and discharging of the lithium battery. The sphere formed by this has an average particle diameter (D50) of about 16-18 μm. The above high temperature heat treatment process is also referred to as a carbonization process, because the asphalt will form a carbon layer at a high temperature due to the process.

It is worth noting that the negative electrode (anode) material is prepared by mixing the ruthenium and the graphite particles by the prior art. In actual use, since the ruthenium particles expand, peel, and fall off, only 100 cycles of charge and discharge cycles are performed, that is, Decline to 80% charge and discharge efficiency. However, through actual testing, the structure in which the two asphalt layers of the ruthenium and graphite particles mixed with the graphite particles are coated in the above process of the present invention is upgraded to a charge and discharge efficiency of 80% after 300 cycles of charge and discharge cycles. As apparent from the above description, the present invention does have an effect that cannot be expected by the prior art.

Further, in the present invention, the discharge process of the lithium ion battery is similar to that shown in Fig. 4. However, the method for producing a carbon nanotube anode material of the lithium ion battery of the present invention is different, and therefore, the battery anode material produced by the present invention is different.

In summary, the purpose of forming the first asphalt layer in the above process is to combine the ruthenium particles and the graphite particles to form a core sphere, and the purpose of forming the second asphalt layer is to form an elasticity between the asphalt and the graphite fine powder. The graphite layer is used for coating, protecting and suppressing the expansion, peeling and shedding of the ruthenium particles, so as to avoid the degradation of the charging and discharging efficiency of the prior art, and to improve the charging and discharging efficiency of the lithium ion battery. Therefore, the present invention has the effects that cannot be achieved by the prior art and conforms to the patent requirements.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the embodiments of the present invention, and the equivalents and modifications of the shapes, structures, materials, features, and spirits described in the claims of the present invention. , should be included in the patent application of the present invention Within the scope.

P‧‧‧ asphalt layer

G‧‧‧graphite particles

Si‧‧‧矽 particles

Claims (8)

A method for manufacturing a carbon nanotube anode material for a lithium ion battery, comprising the steps of: step 310: placing a powder of bismuth, graphite, and pitch into a high-speed mixing granulator, and then adding water, a coupling agent, and a binder; : using the granulator to mix and stir the above mixture, granulating at high speed to produce a viscous mixture; Step 330: drying the viscous mixture in a dryer, heating at a process temperature of 300-500 ° C 10 In an hour, it becomes a nuclear sphere-shaped particle powder in which the cerium particles and the graphite particles are uniformly mixed with each other, and the asphalt forms the outermost asphalt layer surrounding the sphere; Step 340: the 6~9 μm nuclear spheroidal shaped particle powder (70) ~80%) placed in the high-speed mixing granulator, adding 1~3μm asphalt (5~10%) and 3~5μm graphite fine powder (15~20%), then adding water, coupling agent and binder; step 350 : using the granulator to mix and mix the above mixture, granulating at a high speed to form a viscous mixture; and step 360: carbonizing the viscous mixture in a heat treatment carbonization furnace to form a spherical shape Particle powder, and an elastic graphite layer is formed on the surface of the pronuclear sphere. The sphere formed by the particle has an average particle diameter (D50) of 16-18 μm to enhance the coating and protection, and can inhibit the expansion and peeling of the ruthenium particles. Shedding to improve the charge and discharge efficiency of lithium ion batteries. The manufacturing method of claim 1, wherein in step 310, the particle diameters of Silicon, Graphite, and Pitch are: 1 to 2 μm, 3 to 5 μm, and 1 to 3 μm. The weight percentage of the powder is: 3~6%, 91~82%, 6~12%. The manufacturing method of claim 1, wherein in step 320, the process temperature is a chamber Temperature, and process time is 30 minutes to 1 hour. The manufacturing method of claim 1, wherein in step 330, the process temperature is 300 to 500 ° C for 10 hours. The manufacturing method of claim 1, wherein in step 340, the weight percentage of the powder of the nuclear sphere-shaped particles, the pitch, and the graphite fine powder are: 70 to 80%, 5 to 10%, and 15 to 20%. The manufacturing method of claim 1, wherein in step 350, the granulation temperature is room temperature, and the process time is from 30 minutes to 1 hour. The manufacturing method of claim 1, wherein in step 360, the carbonization process temperature is 850 to 900 ° C for 10 to 12 hours. The manufacturing method of claim 1, wherein in step 360, the formed sphere has an average particle diameter (D50) of 16 to 18 μm.