Battery slurry using metal conductive agent and lithium battery

Abstract

The invention discloses battery slurry using a metal conductive agent and a lithium battery. The battery slurry comprises an active substance, a conductive additive, a binder and a solvent, the active substance is lithium transition metal oxide or graphite; the conductive additive comprises a core and a coating layer, the core is metal particles, and the particle size of the metal particles is 10-200 nm; the coating layer is a carbon layer or a polymer layer, and the thickness of the coating layer is 1-20 nm; the mass of the conductive additive accounts for 0.1-5% of the solid content of the slurry; the binder is prepared from polyvinylidene fluoride, polytetrafluoroethylene and carboxymethyl cellulose; the solvent is N-methyl pyrrolidone or deionized water. The metal core provides a low-resistance path, and the coating layer prevents oxidation; stability: the coating layer isolates direct contact between metal and electrolyte, so that side reaction is reduced; process compatibility: the slurry has excellent dispersity and is suitable for the existing coating process; the internal resistance of the battery is reduced by 10%-30%, and the rate capability is improved by more than 20%.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and more particularly to a battery slurry using a metal conductive agent and a lithium battery. Background Technology

[0002] Lithium-ion batteries are widely used in energy storage and power applications due to their high energy density and long cycle life. Electrode slurry is a core component of lithium batteries, and its conductivity directly affects battery performance. Besides the active material, the conductivity of the electrode slurry is mainly provided by conductive additives. Traditional electrode slurries typically use carbon materials such as carbon black, carbon nanotubes, and graphene as conductive additives. While these materials can improve electrode conductivity, they have the following problems: 1. Carbon-based materials have limited conductivity. Although commercially available carbon-based materials have high conductivity, they are difficult to reach the theoretical conductivity of the materials. Furthermore, the conductivity of carbon-based materials varies greatly between different orientations, making it difficult to meet the requirements of high-rate batteries. 2. Some carbon materials have excessively large specific surface areas, leading to increased electrolyte consumption; 3. Conductive networks are prone to breakage due to volume expansion during cycling.

[0003] Therefore, there is an urgent need to develop a metal conductive additive system that combines high conductivity, stability, and compatibility. Summary of the Invention

[0004] Based on the technical problems existing in the background art, the present invention proposes a battery slurry and a lithium battery using a metal conductive agent.

[0005] The present invention proposes a battery slurry using a metal conductive agent, comprising an active material, a conductive additive, a binder, and a solvent; The active material is: lithium transition metal oxide (such as... , , , One of them, and graphite; The conductive additive includes a core and a coating layer. The core is a metal particle (such as silver, copper, nickel or its alloy) with a particle size of 10-200 nm. The coating layer is either a carbon layer or a polymer layer (such as polypyrrole or polyaniline), with a thickness of 1-10 nm. The mass of the conductive additive is 0.1%-5% of the amount of active material added; The adhesive is: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), and carboxymethyl cellulose (CMC). The solvent is either N-methylpyrrolidone (NMP) or deionized water; Its preparation method includes the following steps: S1: Surface modification of metal particles: Disperse metal particles in a solution containing a carbon source (such as glucose) or a monomer (such as pyrrole), and form a coating layer on their surface by hydrothermal method or chemical vapor deposition method. S2: Slurry mixing: The active material, modified metal conductive additive, and binder are mixed in proportion, and after adding solvent, they are dispersed by high-speed shearing to form a uniform slurry.

[0006] A lithium battery includes coating the prepared slurry onto a current collector (aluminum foil or copper foil), drying and rolling it to form an electrode, and assembling it with a separator and an electrolyte to form a lithium-ion battery.

[0007] The beneficial effects of this invention are: 1. High conductivity: The metal core provides a low-resistance path, and the coating layer prevents oxidation; 2. Stability: The coating layer isolates the metal from direct contact with the electrolyte, reducing side reactions; 3. Process compatibility: The slurry has excellent dispersibility and is suitable for existing coating processes; 4. Improved battery performance: Battery internal resistance is reduced by 10%-30%, rate performance is improved by more than 20%, and high-rate cycle life is improved by more than 100%. Attached Figure Description

[0008] Figure 1 These are carbon-coated silver nanoparticles in this invention.

[0009] Figure 2 This is an electron microscope image showing the distribution of metallic conductive agents in the positive electrode of a lithium battery.

[0010] Figure 3 This is the energy spectrum of the distribution of metallic conductive agents in the positive electrode of a lithium battery.

[0011] Figure 4 This is a comparison of the cyclic performance of the embodiments and comparative examples of the present invention. Detailed Implementation

[0012] The present invention will be further explained below with reference to specific embodiments. Example

[0013] refer to Figure 1 As shown, this embodiment proposes a battery slurry using a metal conductive agent, comprising an active material, a conductive additive, a binder, and a solvent; The active material is: lithium transition metal oxide (such as layered oxides). Polyanionic oxides Spinel-type oxides One of the following: graphite, silicon-based, and lithium titanate; The conductive additive includes a core and a coating layer. The core is a metal particle (such as silver, copper, nickel or its alloy) with a particle size of 10-200 nm. The coating layer is one of a carbon layer (amorphous carbon) or a polymer layer (such as polypyrrole or polyaniline), with a thickness of 1-20 nm; The conductive additive accounts for 0.1%-5% of the solid content of the slurry by mass; The adhesive is: polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and polyacrylic acid (PAA). The solvent is either N-methylpyrrolidone (NMP) or deionized water; Its preparation method includes the following steps: S1: Surface modification of metal particles: Disperse metal particles in a solution containing a carbon source (such as glucose) or a monomer (such as pyrrole), and form a coating layer on their surface by hydrothermal method or chemical vapor deposition method. S2: Slurry mixing: The active material, modified metal conductive additive, and binder are mixed in proportion, and after adding solvent, they are dispersed by high-speed shearing to form a uniform slurry.

[0014] The present invention also proposes a lithium battery, comprising coating the above-prepared slurry onto a current collector (aluminum foil or copper foil), drying and rolling to form an electrode, and assembling it with a separator and an electrolyte to form a lithium-ion battery. Example 1

[0015] 1. Silver nanoparticles (50 nm) were dispersed in a glucose solution and subjected to a hydrothermal reaction at 180°C for 6 hours to form carbon-coated silver particles (Ag@C). 2. Mix LiFPO4:Ag@C:PVDF = 97.8:1:1.2 (mass ratio), add NMP solvent, and stir to obtain the positive electrode slurry; 3. Coated onto aluminum foil, dried to form a positive electrode sheet; 4. Mix graphite:Ag@C:CMC:SBR = 97.0:0.5:1.0:1.5 (mass ratio), add deionized water, and stir to obtain the negative electrode slurry; 5. The negative electrode slurry is coated and then dried to form a negative electrode sheet; 6. Assemble the positive and negative electrodes, separator, and electrolyte into a cylindrical battery.

[0016]

[0017] Comparative Example 1 The same proportions of conventional conductive carbon black (Super P) and carbon nanotubes were used to replace Ag@C, with all other conditions remaining the same.

[0018]

[0019] Test Results The internal resistance of the battery in Example 1 is 0.98 mΩ, while that in Comparative Example 1 is 1.78 mΩ. At a 4C discharge rate, Example 1 exhibited a capacity retention of 90%, while Comparative Example 1 showed 72%. The performance comparison table between the examples and comparative examples is shown below:

[0020] The following are the types of materials used in this application:

[0021] Commercially available carbon-based materials are already in mature applications and are not the innovation proposed in this patent.

[0022] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A battery slurry using a metallic conductive agent, characterized in that, This includes active materials, conductive additives, binders, and solvents; The active material is one of lithium transition metal oxide or graphite; The conductive additive includes a core and a coating layer, wherein the core is: metal particles with a particle size of 10-200 nm; The coating layer is either a carbon layer or a polymer layer, with a thickness of 1-20 nm. The conductive additive accounts for 0.1%-5% of the solid content of the slurry by mass; The adhesive is: polyvinylidene fluoride, polytetrafluoroethylene, and carboxymethyl cellulose; The solvent is either N-methylpyrrolidone or deionized water; Its preparation method includes the following steps: S1: Surface modification of metal particles: Disperse metal particles in a solution containing a carbon source or monomer, and form a coating layer on their surface by hydrothermal method or chemical vapor deposition method; S2: Slurry mixing: The active material, modified metal conductive additive, and binder are mixed in proportion, and after adding solvent, they are dispersed by high-speed shearing to form a uniform slurry.

2. A lithium battery, characterized in that, The method includes coating the slurry prepared according to claim 1 onto a current collector, drying and rolling it to form an electrode, and assembling it with a separator and electrolyte to form a lithium-ion battery.

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