Preparation method of carbon nanotube conductive agent slurry based on composite dispersion system and carbon nanotube conductive agent slurry

Abstract

The invention relates to the technical field of conductive paste, in particular to a preparation method of carbon nanotube conductive agent paste based on a composite dispersion system and the carbon nanotube conductive agent paste. The method comprises the following steps: dissolving polyvinylpyrrolidone serving as a main dispersing agent into N-methyl pyrrolidone serving as a solvent, adding styrene-maleic acid copolymer serving as an auxiliary dispersing agent and long-chain organic amine serving as an auxiliary dispersing agent, and uniformly stirring to obtain a mixture containing a composite dispersing system; putting array carbon nanotubes into the mixture, and continuously stirring and dispersing to obtain pre-dispersed conductive paste; and grinding the pre-dispersed conductive paste to prepare the carbon nanotube conductive agent paste. The preparation method of the carbon nanotube conductive agent slurry based on the composite dispersion system can be used for preparing the carbon nanotube conductive agent slurry with high solid content and high stability, and has the advantages of low cost and easiness in operation.

Description

Technical Field

[0001] The present invention relates to the technical field of conductive pastes, and particularly to a preparation method of a carbon nanotube conductive agent paste based on a composite dispersion system and a carbon nanotube conductive agent paste. Background Art

[0002] Carbon nanotube conductive agent paste has become an important material in the battery field due to its excellent electrical conductivity, high stability and low metal impurity content. At present, the preparation process of carbon nanotube conductive agent paste is mainly: mixing carbon nanotubes, water, dispersant polyvinylpyrrolidone (abbreviated as PVP), thickener, etc. and then dispersing them to obtain carbon nanotube conductive agent paste.

[0003] However, the current process for preparing carbon nanotube conductive agent paste still has deficiencies: it mainly uses PVP as the dispersant and N-methylpyrrolidone (abbreviated as NMP) as the solvent, and disperses through a high-speed disperser and a sand mill. Among them, as Figure 1 shown, the PVP monomer has an N-vinylpyrrolidone molecular structure. N-vinylpyrrolidone contains a polar C=O bond and a low-polar carbon chain, which is similar to the hydrophilic and lipophilic combination of surfactants, so it has the function of dispersing pigments and fillers. However, the N atom on the PVP molecular chain is wrapped by three carbons and a cyclic pentane structure, blocking the adsorption of polar N elements to the arrayed carbon nanotubes, affecting the dispersion effect. And the arrayed carbon nanotubes have a super-high specific surface area and a large oil absorption value, which further leads to difficult dispersion, so it is difficult to prepare a carbon nanotube conductive agent paste with a high solid content and high stability. Summary of the Invention

[0004] The purpose of the present invention is to avoid the deficiencies in the prior art and provide a preparation method of a carbon nanotube conductive agent paste based on a composite dispersion system. The preparation method of the carbon nanotube conductive agent paste based on the composite dispersion system can prepare a carbon nanotube conductive agent paste with a high solid content and high stability, and has the advantages of low cost and easy operation.

[0005] To achieve one of the above purposes, the present invention provides the following technical solutions:

[0006] Provide a preparation method of a carbon nanotube conductive agent paste based on a composite dispersion system,

[0007] including the following steps:

[0008] Dissolve the main dispersant polyvinylpyrrolidone in the solvent N-methylpyrrolidone, add the co-dispersant styrene-maleic anhydride copolymer and the co-dispersant long-chain organic amine, and stir evenly to obtain a mixture containing a composite dispersion system;

[0009] Add array carbon nanotubes to the mixture and continue stirring and dispersing to obtain a pre-dispersed conductive paste;

[0010] Grind the pre-dispersed conductive paste to obtain a carbon nanotube conductive agent paste.

[0011] In some embodiments, the dosages of the raw materials are as follows:

[0012] Polyvinylpyrrolidone 1% - 2%

[0013] Styrene-maleic acid copolymer 0.1% - 0.3%

[0014] Long-chain organic amine 0.1% - 0.3%

[0015] Array carbon nanotubes 2% - 5%

[0016] The balance is the solvent N-methylpyrrolidone.

[0017] In some embodiments, the dosages of the raw materials are as follows:

[0018] Polyvinylpyrrolidone 1.28%

[0019] Styrene-maleic acid copolymer 0.2%

[0020] Long-chain organic amine 0.2%

[0021] Array carbon nanotubes 4%

[0022] The balance is the solvent N-methylpyrrolidone.

[0023] In some embodiments, the long-chain organic amine is selected from organic amine VA-22 and / or organic amine VR-01.

[0024] In some embodiments, the mixture is placed in a disperser, and when adding the array carbon nanotubes to the mixture, the disperser stirs synchronously.

[0025] In some embodiments, after adding the array carbon nanotubes to the mixture, first stir and disperse at a first stirring speed of 10 rpm - 20 rpm until the array carbon nanotubes are infiltrated into the mixture, and then stir and disperse at a second stirring speed of 1000 rpm - 3000 rpm until the pre-dispersed conductive paste is obtained.

[0026] In some embodiments, the stirring and dispersing time at the second stirring speed is 25 min - 40 min.

[0027] In some embodiments, the pre-dispersed conductive paste is transferred to a sand mill, and the sand mill is provided with ultrasonic waves to perform ultrasonic grinding on the pre-dispersed conductive paste until the particle size and viscosity of the carbon nanotube conductive agent paste meet the requirements.

[0028] Advantages of the preparation method of the carbon nanotube conductive agent slurry based on a composite dispersion system of the present invention:

[0029] In the preparation method of the carbon nanotube conductive agent slurry based on a composite dispersion system of the present invention, the main dispersant polyvinylpyrrolidone (PVP) of the composite dispersion system is dissolved in the solvent NMP. The PVP molecular chain contains polar C=O bonds and low-polarity carbon chains, similar to the hydrophilic and lipophilic combination of a surfactant. The co-dispersant styrene-maleic acid copolymer of the composite dispersion system: contains low-polarity phenylethyl groups and polar oxygen-containing carboxyl groups, supplementing the surface activity function of the dispersant. The co-dispersant long-chain organic amine of the composite dispersion system utilizes the polarity and electron cloud distribution of its own C=O bond and N-C bond to effectively compensate for the dispersing effect of PVP. Through the combination of PVP, styrene-maleic acid copolymer, and long-chain organic amine, using the polar structures of carbonyl, carboxyl, and amine groups and the non-polar structures of straight-chain long alkyl groups, phenylethyl groups, and short-chain alkylethyl groups, a synergistic effect is generated. This synergistic effect effectively overcomes the hindrance to the adsorption effect of carbon nanotubes after the N atom on the PVP molecular chain is wrapped by the cyclic pentane structure, thereby significantly improving the dispersion effect. Through the optimization of the composite dispersion system, the preparation of a carbon nanotube conductive agent slurry with high solid content and high stability is achieved. Compared with the traditional method that only uses PVP as a dispersant, this composite dispersion system significantly improves the dispersion effect and solves the problem of easy agglomeration of carbon nanotubes.

[0030] A carbon nanotube conductive agent slurry is also provided, which is prepared by the above-mentioned preparation method of the carbon nanotube conductive agent slurry based on a composite dispersion system.

[0031] A battery is also provided, including the above-mentioned carbon nanotube conductive agent slurry. Description of the Drawings

[0032] Figure 1 It is the molecular structure of the PVP monomer N-vinylpyrrolidone.

[0033] Figure 2 It is the property description diagram of the long-chain organic amine VR-01. Detailed Embodiments

[0034] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present invention will be more thorough and complete, and can fully convey the scope of the present invention to those skilled in the art.

[0035] Example 1

[0036] The preparation method of the carbon nanotube conductive agent slurry based on the composite dispersion system disclosed in this embodiment,

[0037] comprises the following steps:

[0038] Dissolve the main dispersant polyvinylpyrrolidone in the solvent N-methylpyrrolidone, add the co-dispersant styrene-maleic acid copolymer and the co-dispersant long-chain organic amine, and stir evenly to obtain a mixture containing a composite dispersion system;

[0039] Specifically, use polyvinylpyrrolidone solution as the main dispersant, put the main dispersant into the solvent N-methylpyrrolidone, and then add the co-dispersant styrene-maleic acid copolymer and the co-dispersant long-chain organic amine to form a composite dispersion system. The main dispersant PVP in this composite dispersion system is dissolved in the solvent NMP, and the co-dispersant styrene-maleic acid copolymer and the co-dispersant long-chain organic amine are also added. In the molecular chain of styrene-maleic acid, there are low-polarity phenylethyl groups and polar oxygen-containing carboxyl groups, which supplement the function of the surfactant-containing dispersant. The long-chain organic amine uses the polarity and electron cloud distribution of its C=O bond and N-C bond to effectively compensate for the dispersion effect of PVP. Therefore, the cooperation of the co-dispersants styrene-maleic acid copolymer and long-chain organic amine with the main dispersant polyvinylpyrrolidone utilizes the polar structures of carbonyl, carboxyl, and amine groups, and the non-polar structures of straight-chain long alkyl groups, pump ethyl groups, and short-chain alkylethyl groups to produce a synergistic effect and improve the dispersion effect.

[0040] Put the array carbon nanotubes into the mixture and continue to stir and disperse to obtain a pre-dispersed conductive paste;

[0041] Add the array carbon nanotubes to the above-mentioned mixture containing the composite dispersion system, so that the composite dispersion system can fully disperse the array carbon nanotubes, and continue to stir and disperse to fully disperse and obtain a pre-dispersed conductive paste.

[0042] Grind the pre-dispersed conductive paste to obtain a carbon nanotube conductive agent slurry.

[0043] Grind the obtained pre-dispersed conductive paste to make the pre-dispersed conductive paste have the corresponding particle size and viscosity, and obtain a carbon nanotube conductive agent slurry.

[0044] In this embodiment, the dosages of each raw material are as follows:

[0045] Polyvinylpyrrolidone 1%

[0046] Styrene-maleic acid copolymer 0.1%

[0047] Organic amine 0.1%

[0048] Array carbon nanotubes 2

[0049] The balance is the solvent N-methylpyrrolidone.

[0050] The dosages of the above raw materials can be adjusted according to the actual situation, and there is no unique limitation here.

[0051] In this embodiment, the styrene-maleic anhydride copolymer is selected from styrene-maleic anhydride copolymer GR-31.

[0052] The above styrene-maleic anhydride copolymer GR-31 is a commercially available product. Among them, the styrene-maleic anhydride copolymer can also be styrene-maleic anhydride copolymers of other brands, and there is no unique limitation here.

[0053] In this embodiment, the long-chain organic amine is selected from organic amine VA-22.

[0054] The above long-chain organic amine VA-22 is a commercially available product, and it can also be long-chain organic amines of other brands, and there is no unique limitation here.

[0055] In this embodiment, the mixture is placed in a disperser, and when the array carbon nanotubes are added to the mixture, the disperser stirs synchronously.

[0056] Specifically, it is such that the mixture containing the composite dispersion system is continuously dispersed in the disperser. At this time, the array carbon nanotubes are added to the mixture while dispersing, so that the array carbon nanotubes can quickly infiltrate into the mixture.

[0057] In this embodiment, after adding the array carbon nanotubes to the mixture, first stir and disperse at a first stirring speed of 10 rpm until the array carbon nanotubes infiltrate into the mixture, and then stir and disperse at a second stirring speed of 1000 rpm until the pre-dispersed conductive paste is obtained.

[0058] Specifically, first stir and disperse at a slower first stirring speed so that the array carbon nanotubes can infiltrate into the mixture, and then use a faster second stirring speed for rapid dispersion.

[0059] In this embodiment, the stirring and dispersing time at the second stirring speed is 25 min.

[0060] Specifically, the stirring and dispersing time at the second stirring speed can be selected according to actual needs.

[0061] In this embodiment, the pre-dispersed conductive paste is transferred to a sand mill, and the sand mill is provided with ultrasonic waves to perform ultrasonic grinding on the pre-dispersed conductive paste. The time of ultrasonic grinding is 60 min until the particle size and viscosity of the carbon nanotube conductive agent paste meet the requirements.

[0062] Using ultrasonic grinding can improve the grinding effect.

[0063] The above uses long-chain organic amine and styrene-maleic acid copolymer as composite dispersants, synergistically with PVP to disperse carbon nanotubes, and obtains a carbon nanotube conductive paste with stable viscosity; uses a sand mill with built-in ultrasonic waves, synergistically with the composite dispersion system, to obtain a carbon nanotube conductive paste with stable viscosity.

[0064] Example 2

[0065] The preparation method of the carbon nanotube conductive agent paste based on the composite dispersion system disclosed in this example

[0066] includes the following steps:

[0067] Dissolve the main dispersant polyvinylpyrrolidone in the solvent N-methylpyrrolidone, add the co-dispersant styrene-maleic acid copolymer and the co-dispersant long-chain organic amine, and stir evenly to obtain a mixture containing a composite dispersion system;

[0068] Specifically, use polyvinylpyrrolidone solution as the main dispersant, put the main dispersant into the solvent N-methylpyrrolidone, and then add the co-dispersant styrene-maleic acid copolymer and the co-dispersant long-chain organic amine to form a composite dispersion system. The main dispersant PVP in this composite dispersion system is dissolved in the solvent NMP, and the co-dispersants styrene-maleic acid copolymer and long-chain organic amine are also added. In the molecular chain of styrene-maleic acid, there are low-polarity phenethyl groups and polar oxygen-containing carboxyl groups, which supplement and form the function of a surfactant dispersant. The long-chain organic amine uses the polarity and electron cloud distribution of its C=O bond and N-C bond to effectively compensate for the dispersion effect of PVP. Therefore, the cooperation of the co-dispersants styrene-maleic acid copolymer and long-chain organic amine with the main dispersant polyvinylpyrrolidone utilizes the polar structures of carbonyl, carboxyl, and amine groups, and the non-polar structures of straight-chain long alkyl groups, pump ethyl groups, and short-chain alkylethyl groups to produce a synergistic effect and improve the dispersion effect.

[0069] Put the array carbon nanotubes into the said mixture, and continue to stir and disperse to obtain a pre-dispersed conductive paste;

[0070] Add the array carbon nanotubes to the above mixture containing the composite dispersion system, so that the composite dispersion system can fully disperse the array carbon nanotubes, and continue to stir and disperse to fully disperse and obtain a pre-dispersed conductive paste.

[0071] Grind the said pre-dispersed conductive paste to obtain a carbon nanotube conductive agent paste.

[0072] Grind the obtained pre-dispersed conductive material so that the pre-dispersed conductive paste has the corresponding particle size and viscosity to obtain a carbon nanotube conductive agent paste.

[0073] In this example, the dosages of each raw material are as follows:

[0074] Polyvinylpyrrolidone 2%

[0075] 0.3% styrene - maleic acid copolymer

[0076] 0.3% organic amine

[0077] 5% arrayed carbon nanotubes

[0078] The balance is the solvent N - methylpyrrolidone.

[0079] The dosages of the above raw materials can be adjusted according to the actual situation, and there is no unique limitation here.

[0080] In this embodiment, the styrene - maleic acid copolymer is selected from styrene - maleic acid copolymer GR - 31.

[0081] The above - mentioned styrene - maleic acid copolymer GR - 31 is a product purchased on the market. Among them, the styrene - maleic acid copolymer can also be styrene - maleic acid copolymers of other brands, and there is no unique limitation here.

[0082] In this embodiment, the long - chain organic amine is selected from organic amine VR - 01.

[0083] The above - mentioned long - chain organic amine VR - 01 is a product purchased on the market. For details, see Figure 2 Among them, the long - chain organic amine VR - 01 can also be long - chain organic amines of other brands, and there is no unique limitation here.

[0084] In this embodiment, the mixture is placed in a disperser. When the arrayed carbon nanotubes are added to the mixture, the disperser stirs synchronously.

[0085] Specifically, the mixture containing the composite dispersion system is continuously dispersed in the disperser. At this time, the arrayed carbon nanotubes are added to the mixture while dispersing, so that the arrayed carbon nanotubes can quickly infiltrate into the mixture.

[0086] In this embodiment, after the arrayed carbon nanotubes are added to the mixture, it is first stirred and dispersed at a first stirring speed of 20 rpm until the arrayed carbon nanotubes infiltrate into the mixture, and then stirred and dispersed at a second stirring speed of 3000 rpm until the pre - dispersed conductive paste is obtained.

[0087] Specifically, it is first stirred and dispersed at a slower first stirring speed so that the arrayed carbon nanotubes can infiltrate into the mixture, and then quickly dispersed at a faster second stirring speed.

[0088] In this embodiment, the stirring and dispersing time at the second stirring speed is 40 min.

[0089] Specifically, the stirring and dispersing time at the second stirring speed can be selected according to actual needs.

[0090] In this embodiment, the pre-dispersed conductive paste is transferred to a sand mill. The sand mill is equipped with ultrasonic waves to ultrasonically grind the pre-dispersed conductive paste. The time of the ultrasonic grinding is 120 min until the particle size and viscosity of the carbon nanotube conductive agent paste meet the requirements.

[0091] Using ultrasonic grinding can improve the grinding effect.

[0092] The above uses organic amine and styrene-maleic acid copolymer as composite dispersants to synergistically disperse carbon nanotubes with PVP to prepare a carbon nanotube conductive paste with stable viscosity; a sand mill with self-contained ultrasonic waves is used in combination with the composite dispersion system to prepare a carbon nanotube conductive paste with stable viscosity.

[0093] Example 3

[0094] The preparation method of the carbon nanotube conductive agent paste based on the composite dispersion system disclosed in this embodiment

[0095] includes the following steps:

[0096] Dissolve the main dispersant polyvinylpyrrolidone in the solvent N-methylpyrrolidone, add the co-dispersant styrene-maleic acid copolymer and the co-dispersant long-chain organic amine, and stir evenly to obtain a mixture containing a composite dispersion system;

[0097] Specifically, use polyvinylpyrrolidone solution as the main dispersant, put the main dispersant into the solvent N-methylpyrrolidone, and then add the co-dispersant styrene-maleic acid copolymer and the co-dispersant long-chain organic amine to form a composite dispersion system. In this composite dispersion system, the main dispersant PVP is dissolved in the solvent NMP, and the co-dispersants styrene-maleic acid copolymer and long-chain organic amine are also added. In the molecular chain of styrene-maleic acid, there are low-polarity phenethyl groups and polar oxygen-containing carboxyl groups, which supplement and form the function of a surfactant dispersant. The long-chain organic amine uses the polarity and electron cloud distribution of its own C=O bond and N-C bond to effectively compensate for the dispersion effect of PVP. Therefore, the cooperation of the co-dispersants styrene-maleic acid copolymer and long-chain organic amine with the main dispersant polyvinylpyrrolidone utilizes the polar structures of carbonyl, carboxyl, and amine groups, and the non-polar structures of straight-chain long alkyl groups, pump ethyl groups, and short-chain alkylethyl groups to produce a synergistic effect and improve the dispersion effect.

[0098] Put the array carbon nanotubes into the mixture and continue to stir and disperse to obtain a pre-dispersed conductive paste;

[0099] Add the array carbon nanotubes to the above mixture containing the composite dispersion system, so that the composite dispersion system can fully disperse the array carbon nanotubes, and continue to stir and disperse to fully disperse and obtain a pre-dispersed conductive paste.

[0100] Grind the pre-dispersed conductive paste to obtain a carbon nanotube conductive agent paste.

[0101] Grind the obtained pre-dispersed conductive material to obtain a corresponding particle size and viscosity for the pre-dispersed conductive paste, and obtain a carbon nanotube conductive agent paste.

[0102] In this embodiment, the dosages of the respective raw materials are as follows:

[0103] Polyvinylpyrrolidone 1.5%

[0104] Styrene-maleic acid copolymer 0.2%

[0105] Organic amine 0.2%

[0106] Array carbon nanotubes 3%

[0107] The balance is the solvent N-methylpyrrolidone.

[0108] The dosages of the above raw materials can be adjusted according to the actual situation, and there is no unique limitation here.

[0109] In this embodiment, the styrene-maleic acid copolymer is selected from styrene-maleic acid copolymer GR-31.

[0110] The above styrene-maleic acid copolymer GR-31 is a commercially available product. Among them, the styrene-maleic acid copolymer can also be styrene-maleic acid copolymers of other brands, and there is no unique limitation here.

[0111] In this embodiment, the long-chain organic amine is selected from organic amine VA-22.

[0112] The above long-chain organic amine VA-22 is a commercially available product, and the long-chain organic amine VA-22 can also be long-chain organic amines of other brands, and there is no unique limitation here.

[0113] In this embodiment, the mixture is placed in a disperser, and when the array carbon nanotubes are added to the mixture, the disperser stirs synchronously.

[0114] Specifically, the mixture containing the composite dispersion system is continuously dispersed in the disperser. At this time, the array carbon nanotubes are added to the mixture while dispersing, so that the array carbon nanotubes can quickly infiltrate into the mixture.

[0115] In this embodiment, after adding the array carbon nanotubes to the mixture, first stir and disperse at a first stirring speed of 15 rpm until the array carbon nanotubes infiltrate into the mixture, and then stir and disperse at a second stirring speed of 1500 rpm until the pre-dispersed conductive paste is obtained.

[0116] Specifically, first stir and disperse at a slower first stirring speed so that the array of carbon nanotubes can infiltrate into the mixture, and then use a faster second stirring speed to quickly disperse.

[0117] In this embodiment, the stirring and dispersing time at the second stirring speed is 30 min.

[0118] Specifically, the stirring and dispersing time at the second stirring speed can be selected according to actual needs.

[0119] In this embodiment, the pre-dispersed conductive paste is transferred to a sand mill, and the sand mill is provided with ultrasonic waves to perform ultrasonic grinding on the pre-dispersed conductive paste. The time of ultrasonic grinding is 70 min until the particle size and viscosity of the carbon nanotube conductive agent paste meet the requirements.

[0120] Using ultrasonic grinding can improve the grinding effect.

[0121] The above uses organic amine and styrene-maleic acid copolymer as composite dispersants to synergistically disperse carbon nanotubes with PVP to prepare a carbon nanotube conductive paste with stable viscosity; uses a sand mill with built-in ultrasonic waves to synergistically prepare a carbon nanotube conductive paste with stable viscosity with a composite dispersion system.

[0122] Example 4

[0123] The preparation method of the carbon nanotube conductive agent paste based on the composite dispersion system disclosed in this embodiment

[0124] includes the following steps:

[0125] Dissolve the main dispersant polyvinylpyrrolidone in the solvent N-methylpyrrolidone, add the co-dispersant styrene-maleic acid copolymer and the co-dispersant long-chain organic amine, and stir evenly to obtain a mixture containing a composite dispersion system;

[0126] Specifically, use polyvinylpyrrolidone solution as the main dispersant, put the main dispersant into the solvent N-methylpyrrolidone, and then add the co-dispersant styrene-maleic acid copolymer and the co-dispersant long-chain organic amine to form a composite dispersion system. In this composite dispersion system, the main dispersant PVP is dissolved in the solvent NMP, and the co-dispersants styrene-maleic acid copolymer and long-chain organic amine are also added. In the molecular chain of styrene-maleic acid, there are low-polarity phenethyl groups and polar oxygen-containing carboxyl groups, which supplement and form the function of a surfactant dispersant. The long-chain organic amine uses the polarity and electron cloud distribution of its C=O bond and N-C bond to effectively compensate for the dispersion effect of PVP. Therefore, the cooperation of the co-dispersants styrene-maleic acid copolymer and long-chain organic amine with the main dispersant polyvinylpyrrolidone utilizes the polar structures of carbonyl, carboxyl, and amine groups, and the non-polar structures of straight-chain long alkyl groups, pump ethyl groups, and short-chain alkylethyl groups to produce a synergistic effect and improve the dispersion effect.

[0127] Add arrayed carbon nanotubes to the mixture and continue stirring and dispersing to obtain a pre-dispersed conductive paste;

[0128] Add the arrayed carbon nanotubes to the above mixture containing the composite dispersion system, so that the composite dispersion system can fully disperse the arrayed carbon nanotubes, and continue stirring and dispersing to fully disperse and obtain a pre-dispersed conductive paste.

[0129] Grind the pre-dispersed conductive paste to obtain a carbon nanotube conductive agent paste.

[0130] Grind the obtained pre-dispersed conductive paste to make the pre-dispersed conductive paste have corresponding particle size and viscosity, and obtain a carbon nanotube conductive agent paste.

[0131] In this embodiment, the dosages of the raw materials are as follows:

[0132] Polyvinylpyrrolidone 1.28%

[0133] Styrene-maleic anhydride copolymer 0.2%

[0134] Organic amine 0.2%

[0135] Arrayed carbon nanotubes 4%

[0136] The balance is solvent N-methylpyrrolidone.

[0137] The dosages of the above raw materials can be adjusted according to the actual situation, and there is no unique limitation here.

[0138] In this embodiment, the styrene-maleic anhydride copolymer is selected from styrene-maleic anhydride copolymer GR-31.

[0139] The above styrene-maleic anhydride copolymer GR-31 is a commercially available product. Among them, the styrene-maleic anhydride copolymer can also be styrene-maleic anhydride copolymers of other brands, and there is no unique limitation here.

[0140] In this embodiment, the long-chain organic amine is selected from organic amine VR-01.

[0141] The above long-chain organic amine VR-01 is a commercially available product, and the details can be seen in Figure 2 . Among them, the long-chain organic amine VR-01 can also be long-chain organic amines of other brands, and there is no unique limitation here.

[0142] In this embodiment, the mixture is placed in a disperser, and when adding the arrayed carbon nanotubes to the mixture, the disperser stirs synchronously.

[0143] Specifically, the mixture containing the composite dispersion system is continuously dispersed in a disperser, and while dispersing, the array carbon nanotubes are added to the mixture, so that the array carbon nanotubes can quickly infiltrate into the mixture.

[0144] In this embodiment, after adding the array carbon nanotubes to the mixture, first stir and disperse at a first stirring speed of 12 rpm until the array carbon nanotubes infiltrate into the mixture, and then stir and disperse at a second stirring speed of 2000 rpm until the pre-dispersed conductive paste is obtained.

[0145] Specifically, first stir and disperse at a slower first stirring speed so that the array carbon nanotubes can infiltrate into the mixture, and then use a faster second stirring speed for rapid dispersion.

[0146] In this embodiment, the stirring and dispersing time at the second stirring speed is 30 min.

[0147] Specifically, the stirring and dispersing time at the second stirring speed can be selected according to actual needs.

[0148] In this embodiment, the pre-dispersed conductive paste is transferred to a sand mill, and the sand mill is equipped with ultrasonic waves to perform ultrasonic grinding on the pre-dispersed conductive paste. The time for ultrasonic grinding is 100 min until the particle size and viscosity of the carbon nanotube conductive agent paste meet the requirements.

[0149] Using ultrasonic grinding can improve the grinding effect.

[0150] The above uses organic amine and styrene-maleic anhydride copolymer as composite dispersants to synergistically disperse carbon nanotubes with PVP to prepare a carbon nanotube conductive paste with stable viscosity; uses a sand mill with built-in ultrasonic waves to synergistically prepare a carbon nanotube conductive paste with stable viscosity with a composite dispersion system.

[0151] Effect verification

[0152] To further illustrate the effect of the carbon nanotube conductive agent paste prepared by the method of the present invention, the following comparative experiments are carried out.

[0153] The formula tables of each experiment are shown in Table 1.

[0154] Table 1

[0155]

[0156] Preparation process of formulation dosage 1#:

[0157] Weigh the materials according to the formula table, pre-dissolve PVP in NMP, and stir evenly.

[0158] Put the array carbon nanotubes into the disperser under stirring, stir slowly at 10 - 20 rpm until complete wetting, the viscosity decreases, then increase the dispersion speed to 1000 - 3000 rpm and disperse for 30 minutes to obtain a pre-dispersed conductive paste;

[0159] Transfer the pre-dispersed conductive paste to a sand mill with ultrasonic, perform ultrasonic sanding for 60 min - 120 min, and detect the particle size and viscosity until the specification requirements are met;

[0160] Discharge the material, perform sealed waterproof packaging, and detect the performance.

[0161] Preparation process of formulation dosage 2#:

[0162] a. Weigh the materials according to the formula table, pre-dissolve PVP in NMP, and then add the co-dispersant styrene-maleic acid copolymer GR-31;

[0163] b. Put the array carbon nanotubes into the disperser under stirring, stir slowly at 10 - 20 rpm until complete wetting, the viscosity decreases, then increase the dispersion speed to 1000 - 3000 rpm and disperse for 30 minutes to obtain a pre-dispersed conductive paste;

[0164] c. Transfer the pre-dispersed conductive paste to a sand mill with ultrasonic, perform ultrasonic sanding for 60 min - 120 min, and detect the particle size and viscosity until the specification requirements are met;

[0165] d. Discharge the material, perform sealed waterproof packaging, and detect the performance.

[0166] Preparation process of formulation dosage 3#:

[0167] a. Weigh the materials according to the formula table, pre-dissolve PVP in NMP, and then add the co-dispersant organic amine VA-22 and stir evenly;

[0168] b. Put the array carbon nanotubes into the disperser under stirring, stir slowly at 10 - 20 rpm until complete wetting, the viscosity decreases, then increase the dispersion speed to 1000 - 3000 rpm and disperse for 30 minutes to obtain a pre-dispersed conductive paste;

[0169] c. Transfer the pre-dispersed conductive paste to a sand mill with ultrasonic, perform ultrasonic sanding for 60 min - 120 min, and detect the particle size and viscosity until the specification requirements are met;

[0170] d. Discharge the material, perform sealed waterproof packaging, and detect the performance.

[0171] Preparation process of formulation dosage 4#:

[0172] a. Weigh the materials according to the formula. Dissolve PVP in NMP in advance, then add the co-dispersant styrene-maleic anhydride copolymer GR-31 and the organic amine VA-22, and stir evenly.

[0173] b. Put the array carbon nanotubes into the disperser under stirring. Stir slowly at 10 - 20 rpm until complete wetting, the viscosity decreases, and then increase the dispersion speed to 1000 - 3000 rpm and disperse for 30 minutes to obtain the pre-dispersed conductive paste.

[0174] c. Transfer the pre-dispersed conductive paste to a sand mill with ultrasonic waves, and perform ultrasonic sanding for 60 min - 120 min. Detect the particle size and viscosity until the specification requirements are met.

[0175] d. Discharge the material, seal it with waterproof packaging, and detect the performance.

[0176] The experimental effects obtained from each formula are shown in Table 2.

[0177] Table 2

[0178]

[0179] As can be seen from Table 2, the viscosity stability of the conductive paste obtained from the formula No. 4 prepared by the composite system is significantly improved. It can be seen that using PVP as the main dispersant, combined with the addition of long-chain organic amine / styrene-maleic anhydride copolymer to form a composite dispersant system, and using a sand mill with ultrasonic waves for grinding, a lithium battery conductive agent paste containing array tubes with a solid content of more than 4% - 5% can be prepared, and the viscosity remains at about 3500 mPa·s.

[0180] Among them, although the main dispersant and co-dispersant are also used in formula No. 2 and formula No. 3, the viscosity and flow state of the conductive paste obtained from formula No. 2 and formula No. 3 are both poor, which shows that only by using two co-dispersants at the same time can the main dispersant be effectively synergized.

[0181] In addition, for the battery prepared by adding the preferred formula No. 4 to the lithium battery positive electrode paste according to the conventional dosage, when the dosage of the conductive agent is reduced to 52% of the normal dosage, good effects are obtained for both the charge and discharge capacity retention rates of the battery. See Table 3 for details.

[0182] Table 3

[0183]

[0184] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorized specification. In all examples shown and discussed herein, any specific values should be construed as merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values.

[0185] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a carbon nanotube conductive agent slurry based on a composite dispersion system, characterized in that: The following steps are involved: The main dispersant polyvinyl pyrrolidone is dissolved in the solvent N-methyl pyrrolidone, and the auxiliary dispersant styrene-maleic acid copolymer and the auxiliary dispersant long-chain organic amine are added, and stirred evenly to obtain a mixture containing a composite dispersion system; Adding array carbon nanotubes into the mixture, and continuing to stir and disperse to obtain a pre-dispersed conductive slurry; The pre-dispersed conductive slurry is ground to obtain a carbon nanotube conductive agent slurry.

2. The method for preparing a carbon nanotube conductive agent slurry based on a composite dispersion system according to claim 1, characterized in that: The amount of each raw material is as follows: Polyvinylpyrrolidone 1%~2% Styrene-maleic acid copolymer 0.1%~0.3% Long chain organic amine 0.1%~0.3% Array carbon nanotubes 2~5% The balance was the solvent N-methylpyrrolidone.

3. The method for preparing a carbon nanotube conductive agent slurry based on a composite dispersion system according to claim 1, characterized in that: The amount of each raw material is as follows: Polyvinylpyrrolidone 1.28% Styrene-maleic acid copolymer 0.2% Long chain organic amine 0.2% Array carbon nanotube 4% The balance was the solvent N-methylpyrrolidone.

4. The method for preparing a carbon nanotube conductive agent slurry based on a composite dispersion system according to any one of claims 1 to 3, characterized in that: The long-chain organic amine is selected from organic amine VA-22 and / or organic amine VR-01.

5. The method for preparing carbon nanotube conductive agent slurry based on a composite dispersion system according to claim 1, characterized in that: The mixture is placed in a disperser, and when the array carbon nanotubes are added to the mixture, the disperser stirs synchronously.

6. The method for preparing carbon nanotube conductive agent slurry based on a composite dispersion system according to claim 1 or 5, characterized in that: After adding the array carbon nanotubes into the mixture, the mixture is first stirred and dispersed at a first stirring speed of 10 rpm to 20 rpm until the array carbon nanotubes are soaked into the mixture, and then stirred and dispersed at a second stirring speed of 1000 rpm to 3000 rpm until the pre-dispersed conductive paste is obtained.

7. The method for preparing carbon nanotube conductive agent slurry based on a composite dispersion system according to claim 6, characterized in that: The stirring and dispersing time at the second stirring speed is 25 min to 40 min.

8. The method for preparing carbon nanotube conductive agent slurry based on a composite dispersion system according to claim 1, characterized in that: The pre-dispersed conductive slurry is transferred to a sand mill, and the sand mill is provided with ultrasonic waves to perform ultrasonic grinding on the pre-dispersed conductive slurry until the particle size and viscosity of the carbon nanotube conductive agent slurry meet the requirements.

9. A carbon nanotube conductive agent slurry, characterized in that: The method is used to prepare the carbon nanotube conductive agent slurry based on the composite dispersion system according to any one of claims 1 to 8.

10. A battery, characterized in that: The present invention comprises the carbon nanotube conductive agent slurry as claimed in claim 9.

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