A kind of conductive agent, its preparation method and lithium ion battery containing the conductive agent

Abstract

The invention relates to a conducting agent. Particularly, the structural formula of the conducting agent contains a substituent represented by a formula I (shown in the specification). The invention further relates to a preparation method of the conducting agent and a lithium ion battery containing the conducting agent. According to the preferred technical scheme of the invention, the molecules of the conducting agent are of a three-arm star-shaped structure and form a conjugate big pi system, and electrons can be effectively transmitted in the conjugate system. The conducting agent and a carbon-phase conducting material are matched to be applied to a lithium ion battery, isolated active material particles and carbon-phase conducting material particles can be effectively crosslinked by virtue of a star-structured molecular chain to form a space conducting network, so that the rate capability of the battery is improved.

Description

Technical field

[0001] This application relates to the field of lithium ion battery materials, and specifically to a conductive agent, a preparation method thereof, and a lithium ion battery containing the conductive agent. Background technique

[0002] Currently, most of the cathode active materials used in lithium-ion batteries are transition metal oxides or transition metal phosphates. They are all semiconductors or insulators and have poor conductivity. Therefore, a conductive agent must be added to improve conductivity.

[0003] From the market point of view, conductive agents mainly include conductive carbon black (Super P), conductive graphite (KS-6), vapor-grown carbon fiber (VGCF), carbon nanotube (CNT) and so on. Super P is characterized by its small particle size and is a popular conductive agent for lithium-ion batteries, with a large market share; conductive graphite acts as a node in the conductive network in the battery to improve the conductivity of the electrode; c...

Examples

preparation example Construction

[0082] In order to achieve the second objective of this application, the preparation method of the conductive agent shown in formula III includes at least the following steps:

[0083] Step 1): Preparation of compound 3

[0084] Compound 1 and compound 2 are subjected to a substitution reaction to obtain compound 3.

[0085] As an improvement of the preparation method of the conductive agent of the present application, the reaction temperature is 100°C to 120°C, the reaction time is 22 to 26 hours, and tris(dibenzylideneacetone)dipalladium is added as a catalyst during the reaction. Phenyl) phosphorus acts as a ligand. Compound 1: Compound 2: Tris (dibenzylideneacetone) dipalladium: tris (o-methylphenyl) phosphorus in a molar ratio of 1.55 to 1.75: 1.85 to 2.05: 0.035 to 0.055: 0.145 to 0.175. The reaction is carried out in an inert gas.

[0086]

[0087] Step 2): Preparation of compound 4

[0088] Compound 3 is subjected to substitution reaction with N-bromosuccinimide to obtain com...

Embodiment 1～3

[0107] The structural formulas of the conductive agents of Examples 1 to 3 are shown in Formula III, and the specific selection of substituents is shown in Table 1:

[0108]

[0109]

[0110] Table 1

[0111] Example

R 11 , R 21 , R 31

R 12 , R 22 , R 32

R 13 , R 23 , R 33

R 14 , R 24 , R 34

R 15 , R 25 , R 35

Example 1

Hexyl

Hexyl

2-ethylhexyl

2-ethylhexyl

-F

Example 2

Isopropyl

Isopropyl

Sinki

Sinki

-F

Example 3

Phenyl

Phenyl

Methoxy

Methoxy

-F

[0112] Specifically, the preparation method of the conductive agent shown in Example 1 is:

[0113] Step 1): Preparation of compound 3

[0114] The N-2-ethylhexyl-5-fluoro-6'-bromoisoindigo (4820mg, 8.2mmol), 3,4'-dihexyl-(2,2'-dithiophene)-5-trimethyl Stannane (4940mg, 9.8mmol), tris(dibenzylideneacetone) dipalladium (190mg, 0.2mmol) and tris(o-methylphenyl)phosphorus (250mg, 0.83mmol) were added to a 500mL dry round bottom flask. The flask was repeatedly evacuated and filled with argon. After the atmosphere in th...

Technical field

[0001] This application relates to the field of lithium ion battery materials, and specifically to a conductive agent, a preparation method thereof, and a lithium ion battery containing the conductive agent. Background technique

[0002] Currently, most of the cathode active materials used in lithium-ion batteries are transition metal oxides or transition metal phosphates. They are all semiconductors or insulators and have poor conductivity. Therefore, a conductive agent must be added to improve conductivity.

[0003] From the market point of view, conductive agents mainly include conductive carbon black (Super P), conductive graphite (KS-6), vapor-grown carbon fiber (VGCF), carbon nanotube (CNT) and so on. Super P is characterized by its small particle size and is a popular conductive agent for lithium-ion batteries, with a large market share; conductive graphite acts as a node in the conductive network in the battery to improve the conductivity of the electrode; c...

Examples

preparation example Construction

[0082] In order to achieve the second objective of this application, the preparation method of the conductive agent shown in formula III includes at least the following steps:

[0083] Step 1): Preparation of compound 3

[0084] Compound 1 and compound 2 are subjected to a substitution reaction to obtain compound 3.

[0085] As an improvement of the preparation method of the conductive agent of the present application, the reaction temperature is 100°C to 120°C, the reaction time is 22 to 26 hours, and tris(dibenzylideneacetone)dipalladium is added as a catalyst during the reaction. Phenyl) phosphorus acts as a ligand. Compound 1: Compound 2: Tris (dibenzylideneacetone) dipalladium: tris (o-methylphenyl) phosphorus in a molar ratio of 1.55 to 1.75: 1.85 to 2.05: 0.035 to 0.055: 0.145 to 0.175. The reaction is carried out in an inert gas.

[0086]

[0087] Step 2): Preparation of compound 4

[0088] Compound 3 is subjected to substitution reaction with N-bromosuccinimide to obtain com...

Embodiment 1～3

[0107] The structural formulas of the conductive agents of Examples 1 to 3 are shown in Formula III, and the specific selection of substituents is shown in Table 1:

[0108]

[0109]

[0110] Table 1

[0111] Example

R 11 , R 21 , R 31

R 12 , R 22 , R 32

R 13 , R 23 , R 33

R 14 , R 24 , R 34

R 15 , R 25 , R 35

Example 1

Hexyl

Hexyl

2-ethylhexyl

2-ethylhexyl

-F

Example 2

Isopropyl

Isopropyl

Sinki

Sinki

-F

Example 3

Phenyl

Phenyl

Methoxy

Methoxy

-F

[0112] Specifically, the preparation method of the conductive agent shown in Example 1 is:

[0113] Step 1): Preparation of compound 3

[0114] The N-2-ethylhexyl-5-fluoro-6'-bromoisoindigo (4820mg, 8.2mmol), 3,4'-dihexyl-(2,2'-dithiophene)-5-trimethyl Stannane (4940mg, 9.8mmol), tris(dibenzylideneacetone) dipalladium (190mg, 0.2mmol) and tris(o-methylphenyl)phosphorus (250mg, 0.83mmol) were added to a 500mL dry round bottom flask. The flask was repeatedly evacuated and filled with argon. After the atmosphere in th...

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