TWI570181B - Applicable to silicon - containing composite materials and negative for silicon - containing batteries Material composition - Google Patents

Description

Bismuth-containing composite material for negative electrode of lithium ion battery and negative Pole material composition

The invention relates to a material suitable for a negative electrode of a lithium ion battery, in particular to a ruthenium-containing composite material and a negative electrode material composition suitable for a negative electrode of a lithium ion battery.

Lithium-ion batteries have been widely used in notebook computers, mobile phones, digital cameras, video cameras, PDAs, Bluetooth headsets, and wireless 3C products. For secondary lithium-ion batteries that have been commercialized in the market, carbonaceous materials are mostly used as negative electrodes, for example, mesocarbon microbeads (MCMB, credit capacity: 310 mAh/g) or artificial graphite (grams). The capacity is 350mAh/g). However, the carbon-based anode material has reached the bottleneck of the theoretical capacity of 372 mAh/g, which cannot meet the demand for high-power and high-energy-density lithium batteries.

Compared with graphite materials, tantalum materials have a considerable theoretical specific capacitance (4200mAh/g), which is about one order of magnitude higher than graphite materials (372mAh/g), so it is used as a new secondary lithium-ion battery anode material. . However, during the charging and discharging process of the lithium ion battery, the lithium ion is repeatedly embedded and embedded in the tantalum negative electrode material, so that the tantalum negative electrode material expands and contracts, and the volume expansion ratio can be as high as 400%, after charging and discharging. Will cause 矽 The negative electrode material is cracked, which increases the internal impedance and reduces the service life of the lithium battery.

At present, the graphite-enamel mixed anode material 1 or the pure tantalum anode material is prepared by adding graphite 11 to a mixed solution of a solvent and a binder 12, and then adding a material such as tantalum powder 13 and conductive carbon powder 14 (if it is a pure tantalum anode) The material is not added with the above graphite 11), so that the binder 12 bonds the graphite 11, the tantalum powder 13 and the conductive carbon powder 14 to form the tantalum negative electrode material 1 suitable for the negative electrode of the lithium ion battery; however, as shown in FIG. In the tantalum negative electrode material 1 obtained by the above method, there is a case where the tantalum powder 13 is not completely uniformly dispersed and agglomerated with each other. When the tantalum anode material 1 is actually used as the anode of the lithium ion battery, once the agglomerated tantalum powder 13 is expanded in all directions due to lithium ion intercalation, the tantalum anode material 1 is cracked, and the capacity of the lithium battery cannot be maintained stable. Significantly shorten the life of the lithium-ion battery.

Therefore, it is still an urgent problem to find a lithium ion negative electrode material which has a long service life, is not easy to be cracked, and is easy to manufacture.

Accordingly, a first object of the present invention is to provide a ruthenium-containing composite material suitable for use in a negative electrode material for a lithium ion battery.

Therefore, the present invention is applicable to a ruthenium-containing composite material for a negative electrode material of a lithium ion battery, comprising: a plurality of ruthenium particles; and a porous coating layer coated on the surface of the ruthenium particles; wherein the ruthenium layer has a non- A crystalline structure comprising a partially cleaved sulfonated polyaryl ether ketone.

A second object of the present invention is to provide a negative electrode material composition suitable for a lithium ion battery.

Therefore, the present invention is applicable to a negative electrode material composition of a lithium ion battery, comprising: a conductive material comprising a carbonaceous material having a plurality of carbonaceous particles; and an active material unit comprising a ruthenium-containing composite material, The ruthenium-containing composite material is as described above and dispersed between the carbonaceous particles; and an additive unit comprising a binder that bonds the carbonaceous particles to the ruthenium-containing composite material.

The effect of the present invention is that the ruthenium-containing composite material comprises a porous coating layer covering the surface of the ruthenium particles. When used as a negative electrode material for a lithium battery, the ruthenium particles are not easily cracked, and the stability of the lithium battery can be improved.

1‧‧‧Graphite-enamel mixed anode material

11‧‧‧ graphite

12‧‧‧Adhesive

13‧‧‧矽 powder

14‧‧‧ Conductive toner

Other features and effects of the present invention will be apparent from the following description of the drawings, wherein: FIG. 1 is a schematic diagram illustrating a prior art tantalum negative electrode material; FIG. 2 is an SEM image illustrating Embodiment 1 FIG. 3 is a capacitance-potential relationship diagram illustrating the results of the first charge and discharge cycle test of Example 1; FIG. 4 is a capacitance-potential relationship diagram illustrating the charge and discharge of Comparative Example 2 Figure 5 is a charge-discharge cycle-to-final capacity relationship diagram illustrating the results of the charge-discharge cycle test of Example 1; and Figure 6 is a charge-discharge cycle-to-final capacity relationship diagram, illustrating Comparative Example 1 The results of the charge and discharge cycle test.

The ruthenium-containing composite material of the present invention comprises a plurality of ruthenium particles and a porous coating layer coated on the surface of the ruthenium particles; wherein the coating layer has an amorphous structure, and the amorphous structure includes a portion Cleaved sulfonated polyaryl ether ketone.

The porous coating layer has the function of dispersing and bonding the particles of the crucible. The purpose of partial cleavage of the sulfonated polyaryl ether ketone is to open a portion of the benzene ring of the polyaryl ether ketone to crosslink the sulfonated polyaryl ether ketones to each other to form a partially cleavable elastic group. Sulfonated polyaryl ether ketone. When the partially cleaved sulfonated polyaryl ether ketone is coated on the surface of the ruthenium particles, even if the ruthenium particles expand and contract during charge and discharge, the partially cleaved sulfonated polyaryl ether ketone can be kept draped. Covering the ruthenium particles, maintaining a plurality of ruthenium particles in a state of being dispersed with each other, so when used as a negative electrode material of a lithium battery, the ruthenium particles can withstand the stress generated by volume expansion of lithium ions after bonding, and are not easily broken, and can promote lithium. The stability of the ion battery.

Preferably, the polyaryl ether ketone is selected from the group consisting of polyether ketone (PEK), polyether ether ketone (PEEK), polyetherketoneketone (PEKK), Poly(ether ether ketone ketone), abbreviated as PEEKK, polyetherketoneetherketoneketone (PEKEKK), and a combination thereof.

Preferably, the amorphous structure is a partially cleaved sulfonated polyetheretherketone.

Preferably, the warp portion is based on the total weight of the ruthenium-containing composite material The content of the split sulfonated polyaryl ether ketone ranges from 1 to 20% by weight, and the content of the cerium particles ranges from 80 to 99% by weight. More preferably, the partially cleaved sulfonated polyaryletherketone is present in an amount ranging from 3 to 10% by weight based on the total weight of the cerium-containing composite material, and the cerium particles are present in an amount ranging from 90 to 97% by weight.

The shape of the ruthenium particles is not particularly limited, and preferably, the ruthenium particles have a particle diameter ranging from 200 nm to 2 μm.

Preferably, the amorphous structure is obtained by partial cleavage of the sulfonated polyaryl ether ketone under infrared irradiation by infrared catalysis.

Preferably, the amorphous structure further comprises graphene. The graphene contributes to electrical conductivity and can act as a dispersing agent, and the graphene-like graphene and the partially cleaved sulfonated polyaryletherketone are irregularly interspersed with each other, and the two are electrically repelled. Naturally, there is a gap, and lithium ions can be combined or separated from the ruthenium particles through the slit during charging and discharging, thereby reducing the volume expansion caused by the combination with the lithium ions.

The present invention is applicable to a negative electrode material composition of a lithium ion battery, comprising: a conductive material comprising a carbonaceous material having a plurality of carbonaceous particles; and an active material unit comprising a ruthenium-containing composite material, the The ruthenium composite material is as previously described and dispersed between the carbonaceous particles; and an additive unit comprising a binder that bonds the carbonaceous particles to the ruthenium-containing composite material.

Preferably, the conductive material is contained in an amount ranging from 0.1 to 15% by weight based on 100% by weight of the negative electrode material composition, and the active material sheet is The content of the element ranges from 75 to 98.9 wt%, and the content of the additive unit ranges from 1 to 10 wt%.

Preferably, the carbonaceous material can be, for example, but not limited to, soft carbon, hard carbon (pyrocarbon), amorphous carbon material, graphite particles, conductive carbon powder, and a combination of the foregoing. More preferably, the carbonaceous material is a conductive carbon powder having a particle diameter of 5 to 30 μm.

Preferably, the binder is at least one compound selected from the group consisting of polyvinylidene fluoride (PVDF), polyvinylidine chloride, polyfluoroethylene (polyfluoroethylene) Vinylidene), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone (polyvinyl) Pyrrolidone), tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated ethylene-propylene-diene Polymer, styrene butadiene rubber (SBR), fluorine rubber, and combinations of the foregoing. Among them, styrene-butadiene rubber or the like has a hydrophilic group, and polyfluorinated diethylene or the like has a lipophilic group. More preferably, the binder is at least one compound selected from the group consisting of styrene-butadiene rubber, carboxymethyl cellulose, and combinations of the foregoing.

The preparation method of the negative electrode material composition suitable for a lithium ion battery can be, for example but not limited to: Dissolving a monosulfonated polyaryl ether ketone solid in a solvent to form a sulfonated polyaryl ether ketone solution; adding graphene to the sulfonated polyaryl ether ketone solution to form a suspension solution, Further adding a conductive material and a plurality of ruthenium particles in sequence, and uniformly stirring to form a first mixture slurry; and partially lysing the sulfonated polyaryl ether ketone by the infrared cleavage method to form a partial portion The sulfonated sulfonated polyaryl ether ketone is coated on the ruthenium particles to prepare the negative electrode material composition.

The kinds of the polyaryl ether ketone, the solvent, and the conductive material and their variations are as described above, and will not be described herein.

The present invention will be further illustrated by the following examples, but it should be understood that this embodiment is intended to be illustrative only and not to be construed as limiting.

<Example 1 and Comparative Examples 1 to 2>

[Preparation of a negative electrode material composition suitable for a lithium ion battery]

[Example 1]

The monosulfonate solution and a polyaryletherketone are mixed at 50 to 80 ° C to sulfonate the polyaryl ether ketone, followed by washing with ice water and then curing to obtain a sulfonated polyaryl ether ketone solid. (The sulfur content after curing is 5 to 15% by weight)

The sulfonated polyaryletherketone solid is dissolved in dimethyl hydrazine (DMSO), then graphene, carbon black as a conductive material (particle size 5 to 10 μm), and a plurality of cerium particles (particle size) 200 nm to 2 μm) forming a first mixture slurry, irradiating the first mixture slurry with infrared rays to form a partially cleaved sulfonated polyaryl ether ketone, and subjecting the partially cleaved sulfonated polyaryl group The ether ketone is coated on a plurality of cerium particles (particle diameters of 200 nm to 2 μm) to form a second mixture slurry. The solids portion of the second mixture slurry was 9.8 wt% carbon black, 0.2 wt% graphene, 10 wt% of the sulfonated polyaryl ether ketone solids, and 80 wt% bismuth particles.

Take a round copper-shaped copper foil substrate (area 1.33cm ² ), remove the oxides and organic pollutants on the surface of the copper foil substrate by grinding, and improve the surface flatness, and then insert the ultrasonic solution in acetone and ethanol solution. The oil film and the like are cleaned on the substrate by shaking, and then the second mixture slurry is uniformly stirred by a stirrer, and about 3 mg is applied to the substrate by a doctor blade, and solidified by infrared irradiation to form a negative electrode material. A porous coating layer comprising a partially cleaved sulfonated polyaryl ether ketone is coated on the ruthenium particles. The above-described method can produce the ruthenium-containing composite material and the negative electrode material composition of Example 1.

The SEM photograph of the ruthenium-containing composite of Example 1 is shown in FIG.

[Comparative Example 1]

The polyfluorinated diethylene is dissolved in water to form a binder solution. Adding carbon black to the binder solution to stir completely to form a first mixture slurry, and then adding a plurality of tantalum powders (particle diameters of 200 nm to 2 μm) to the first mixture slurry, and stirring until completely uniform Thereafter, the tantalum powder was uniformly dispersed in the first mixture slurry and a negative electrode slurry containing a plurality of tantalum powder of Comparative Example 1 was formed.

Take a round copper foil substrate (area 1.33cm ² ), remove the oxides and organic contaminants on the copper foil substrate by grinding, and improve the surface flatness, then place it in acetone and ethanol solution to supersonic The oil film and the like are cleaned on the substrate by the oscillating method, and then the negative electrode slurry containing a plurality of powders is uniformly stirred by a stirrer, and about 3 mg is applied to the substrate by a doctor blade, and dried until the solvent is removed. Next, hot pressing (80-150 ° C) was carried out to make the test piece more dense, and the negative electrode material of Comparative Example 1 was obtained.

[Comparative Example 2]

The preparation method of the ruthenium-containing composite particles and the negative electrode material of Comparative Example 2 was substantially the same as that of Example 1, except that the sulfonated polyaryl ether ketone was not irradiated with infrared rays. The first mixture slurry was directly applied to the substrate by a doctor blade, and dried until the solvent was removed, followed by hot pressing (80-150 ° C) to make the test piece more dense.

[How to make lithium-ion half-cells]

Lithium metal is used as the opposite electrode, conductive carbon is used as the guiding agent, carboxymethyl cellulose and styrene-butadiene rubber are used as the bonding agent, and the negative electrode powder is bonded to the copper metal foil by the bonding agent to obtain a negative electrode material. The negative electrode material prepared in the examples or the comparative examples and the foregoing positive electrode material, a polypropylene (PP) separator, and an electrolyte solution using LiPF ₆ as a solute, and a CR2032 module were used to form a button type battery by a conventional method.

<Property test>

[Charge and discharge cycle test]

At 25 ° C, the charge and discharge range is 0 to 1.5 V, and a charge-discharge current of 0.1 C is formed. The capacitance-charge relationship diagrams of the first charge and discharge cycles of Example 1 and Comparative Example 2, and the charge-discharge cycle number-final capacity relationship diagrams of Example 1 and Comparative Example 1 were plotted.

In Figures 3 and 4, cc represents charging and dc represents discharging. Such as As shown in FIG. 3, the first charge amount of Example 1 was 2450 mAh/g, and the first discharge was started by 2150 mAh/g, and the first cycle coulombic efficiency was 88%. As shown in FIG. 4, although the first charge amount of Comparative Example 2 was 2350 mAh/g, the first discharge was started at 1400 mAh/g, and the first cycle coulombic efficiency was 60%. In Comparative Example 2, the amount of electricity was greatly attenuated only after one charge-discharge cycle, presumably because the ruthenium-containing composite materials in the negative electrode material did not contain the porous coating layer of the partially cleaved sulfonated polyaryletherketone. The ruthenium-containing composite material cannot uniformly withstand the stress change of lithium ion in and out and sputum particle expansion during charge-discharge, which causes the ruthenium particles to be broken due to expansion and contraction, thereby causing the negative electrode to crack and lose contact with the electrode plate and the conductive carbon black. It is no longer possible to perform charge-discharge, and the battery power is reduced.

As shown in FIG. 6 , the negative electrode material of Comparative Example 1 contains only tantalum powder, a binder, and carbon black, and does not contain any ruthenium-containing composite particles. At a current of 1 C, the charge amount of the first charge discharge cycle is about 3200 mAh/g. The third charge was about 2100 mAh/g, and the charge for the 10th time was only 500 mAh/g. As shown in FIG. 5, the first embodiment contains the ruthenium-containing composite material. When the current is 1 C, the charge amount of the first charge discharge cycle is about 950 mAh/g, and the charge amount of the second to sixteen times is stably maintained at about 850mAh/g. As apparent from the above, the battery containing the negative electrode material of the ruthenium-containing composite material of the present invention has a small degree of potential drop as the number of charge-discharge cycles increases, and the capacity is stable and the service life is long.

In summary, the present invention is applicable to a lithium-ion battery anode material containing a porous coating layer, which can buffer the stress change caused by the expansion of the tantalum particles during charging, when used in a lithium ion battery. In the case of the negative electrode material, the negative electrode material can have good stability and long service life, so that the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, All remain within the scope of the invention patent.

Claims (5)

A ruthenium-containing composite material comprising: a plurality of ruthenium particles; and a porous coating layer coated on the surface of the ruthenium particles; wherein the ruthenium layer has an amorphous structure, the amorphous structure including Partially cleaved sulfonated polyaryl ether ketone, the partially cleaved sulfonated polyaryl ether ketone is formed by sulfonated polyaryl ether ketone catalyzed by infrared irradiation, and total of the yttrium-containing composite material The content of the partially cleaved sulfonated polyaryl ether ketone ranges from 1 to 20% by weight, and the content of the cerium particles ranges from 80 to 99% by weight. The cerium-containing composite material according to claim 1, wherein the polyaryl ether ketone is selected from the group consisting of polyether ketone, polyether ether ketone, polyether ketone ketone, poly(ether ether ketone ketone), and polyether ketone ether. Ketoketone, and a combination of the foregoing. The ruthenium-containing composite material of claim 1, wherein the amorphous structure is a partially cleaved sulfonated polyetheretherketone. The ruthenium-containing composite material according to claim 1, wherein the ruthenium particles have a particle diameter ranging from 200 nm to 1 μm. A negative electrode material composition suitable for a lithium ion battery, comprising: a conductive material comprising a carbonaceous material having a plurality of carbonaceous particles; and an active material unit comprising a cerium-containing composite material, the cerium a composite material as described in claim 1 and dispersed between the carbonaceous particles; An additive unit comprising a binder that bonds the carbonaceous particles to the ruthenium-containing composite.