CN-117003934-B - High voltage resistant dispersion polymer, conductive paste, electrode paste, and method for producing the same

Abstract

The invention discloses a high-voltage resistant dispersion polymer, a conductive paste and an electrode paste and preparation methods thereof. The high voltage resistant dispersion polymer comprises at least two components including an A component as an anchor point and an alkane B component which reduces rigidity of the polymer, wherein the energy level difference between the HOMO energy level and the LUMO energy level of the A component is not less than 0.1, the energy level difference between the HOMO energy level and the LUMO energy level of the B component is not less than 0.2, and the molecular weight of the B component is 120-200. The component A is used for enhancing the binding function of the dispersion polymer and the CNT, and the component B reduces the rigidity of the dispersion polymer and is better dissolved in the solvent. The energy levels of the component A and the component B are controlled, and the solvent dissolved in the conductive paste can be satisfied on the premise that acting force exists between the component A and the CNT. A battery made of the carbon nanotube conductive paste containing the dispersed polymer has excellent high voltage resistance and electrical cycle properties.

Inventors

• ZUO BO
• ZHU YE
• ZHAO BEI
• MAO OU
• ZHANG MEIJIE
• ZHENG TAO

Assignees

• 江苏天奈科技股份有限公司

Dates

Publication Date

20260508

Application Date

20220429

Claims (5)

1. 1. The conductive paste is characterized by comprising a high-voltage resistant dispersion polymer, carbon nano tubes and a solvent, wherein the high-voltage resistant dispersion polymer is formed by polymerizing A, B components, and the mass ratio of the carbon nano tubes to the high-voltage resistant dispersion polymer is (1-5): 1; The component A is styrene, and the component B is butyl methacrylate; Or, the A component is acrylonitrile, and the B component is octadecyl methacrylate; or, the A component is acrylonitrile and the B component is N-vinyl pyrrolidone.
2. 2. The conductive paste of claim 1, wherein the high voltage resistant dispersion polymer is prepared by uniformly mixing component A, component B and initiator in a molar ratio of 1 (0.1-3) (0.0005-0.01), and reacting in a nitrogen atmosphere at a temperature of 50-110deg.C at 7-20 h.
3. 3. The conductive paste of claim 1, wherein the high voltage resistant dispersion polymer is prepared by mixing component A, component B and initiator in a molar ratio of 1 (0.5-2) (0.0005-0.005), adding solvent, reacting under nitrogen atmosphere at 7-20 h and reaction temperature of 50-90deg.C.
4. 4. The conductive paste of claim 3, wherein the solvent is N-methylpyrrolidone.
5. 5. An electrode paste characterized by comprising the conductive paste, a conductive active material and a binder according to any one of claims 1 to 4, wherein the addition amount of the conductive paste is 0.5 to 2%.

Description

High voltage resistant dispersion polymer, conductive paste, electrode paste, and method for producing the same Technical Field The invention relates to the field of battery application, in particular to a high-voltage resistant dispersion polymer, a conductive paste and an electrode paste and a preparation method thereof. Background The conductive agent is an important component of the lithium battery, and has the primary function of improving the electronic conductivity, and in order to ensure that the electrode has good charge and discharge performance, a certain amount of conductive agent is generally added during the manufacture of the electrode plate, so that an extra contact point is provided for electrode active particulate matters, the contact resistance between electrode materials is reduced, and the electrode has the important function of improving the cycle performance, the capacity and the multiplying power performance of the battery. In addition, the conductive agent can also improve the processability of the pole piece, promote the infiltration of electrolyte to the pole piece, and simultaneously can effectively improve the migration rate of lithium ions in an electrode material, reduce polarization, thereby improving the charge and discharge efficiency of the electrode and the service life of a lithium battery. As with lithium ion battery electrode materials, conductive agents are evolving continuously. From the earliest carbon black materials, the characteristic is that the point-shaped conductive agent, which can also be called as zero-dimensional conductive agent, is mainly used for improving the conductivity through the point contact between particles, and the conductive agent with one-dimensional structure, such as conductive carbon fiber and carbon nano tube, is gradually developed to the later, because of the fibrous structure, the contact with electrode material particles is increased, the conductivity of the electrode is greatly improved, and the resistance of the electrode sheet is reduced. Compared with the traditional granular conductive agents (carbon black, graphite, acetylene black and the like), the carbon nano-tubes (CNTs) are taken as typical nano one-dimensional carbon materials, have excellent electric and heat conduction characteristics, higher length-diameter ratio and mesoporous structure easy for lithium ion shuttling, and can form an effective three-dimensional high-conductivity network among battery active substances under lower addition amount, so that the carbon nano-tubes are expected to replace the traditional granular conductive agents and are applied to the design and production and manufacture of high-end lithium batteries. However, due to the strong pi-pi interactions and van der Waals forces between the bundles of CNTs, currently commercial CNTs are required to be used together with a polymer having a dispersion effect, prepared into various slurries through sanding, ultrasonic processing, etc., and finally applied to lithium batteries in the form of slurries. Therefore, various physicochemical properties of the dispersant polymer directly or indirectly affect the circularity and stability of the lithium battery. At present, the physical dispersing agents of CNTs can be divided into two major types, namely polymers and amphiphilic small molecular compounds, such as Sodium Dodecyl Sulfate (SDS), sodium Dodecyl Benzene Sulfate (SDBS), steroid active agents, porphyrines and aromatic ring small molecular compounds modified by ammonia bromine, wherein the structures of the aromatic ring small molecular compounds often contain charges or active groups (-OH, -COOH and the like), and the active groups are unstable due to oxidation-reduction reaction under electrochemical reaction, so that the aromatic ring small molecular compounds are less applied to lithium batteries. High molecular polymers such as polyvinylpyrrolidone (PVPK 30) and carboxymethylcellulose (CMC) are widely used as CNT dispersing agents, and have better stability in electrochemical reactions. With the rapid development of the lithium battery field, the market has put forward higher and higher requirements on performances such as the cycling performance, the high voltage resistance and the like of the lithium battery, like common polyvinylpyrrolidone (PVPK 30) does not resist high voltage, and the current application demands put forward higher performance requirements on the high voltage resistance and the cycling performance of the CNT dispersing agent. However, a good CNT polymer dispersant presents a number of technical barriers, and many factors such as solvent solubility, CNT encapsulation, positive electrode material compatibility, or positive electrode material contact should be considered in the development process. Based on the above, the CNT used as a conductive agent in the market is currently a product with high cycle characteristics and is industrially applicable to mass production, an