Current collector and preparation method thereof, secondary battery, battery module, battery pack, and electric apparatus

1. A current collector, comprising:

a support layer;

a binder layer; and

a metal layer, wherein

the binder layer is arranged between the support layer and the metal layer;

the binder layer comprises an organic binder and inorganic particles;

a thickness D 0 of the binder layer is 1.0-5.0 μm; and

the inorganic particles comprise large particles with a median particle size D 50large and small particles with a median particle size D 50small , and the median particle sizes of the large particles and the small particles satisfy the following relationships:

D 50large >D 50small ;

D 50large =(0.5-0.9)× D 0 ; and

D 50small =(0.1-0.4)× D 0 .

2. The current collector according to claim 1 , wherein based on a total mass of the binder layer, a mass percentage of the inorganic particles is 50 wt % to 85 wt %.

3. The current collector according to claim 1 , wherein based on a total mass of the inorganic particles, a mass percentage of the large particles is 70 wt % to 90 wt % and the mass percentage of the small particles is 10 wt % to 30 wt %.

4. The current collector according to claim 1 , wherein the median particle size D 50large of the large particles is greater than 700-4500 nm; and/or, the median particle size D 50small of the small particles is 100-2000 nm.

5. The current collector according to claim 1 , wherein the binder layer further comprises carbon nanotubes.

6. The current collector according to claim 5 , wherein, relative to the total mass of the binder layer, a mass percentage of the carbon nanotubes is less than or equal to 10%.

7. The current collector according to claim 1 , wherein the inorganic particles are selected from one or more of aluminum oxide, silicon carbide, silicon nitride, silicon oxide, calcium oxide, boehmite, titanium dioxide, zirconium dioxide, magnesium oxide, zinc oxide, barium sulfate, and boron carbide.

8. The current collector according to claim 1 , wherein the support layer comprises one or more of polyamide, polyimide, polyethylene glycol terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, polypropylene ethylene, acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol, polystyrene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, sodium polystyrene sulfonate, polyacetylene, silicone rubber, polyoxymethylene, polyphenylene oxide, polyphenylene sulfide, polyethylene glycol, polythiaxyl, polyphenyl, polypyrrole, polyaniline, polythiophene, polypyridine, cellulose, starch, protein, epoxy resin, phenolic resin, derivatives thereof, crosslinked products thereof, and copolymers thereof.

9. The current collector according to claim 1 , wherein the organic binder is selected from one or more of polypropylene, carboxymethyl cellulose, polyacrylate, styrene-butadiene rubber, polyacrylic acid sodium, polyurethane, polyethyleneimine, polyvinylidene fluoride, neoprene, nitrile rubber, silicone rubber, polyvinyl acetate, urea-formaldehyde resin, phenolic resin, epoxy resin, silane coupling agent, titanate coupling agent, zirconium coupling agent, aluminate coupling agent, and borate coupling agent.

10. The current collector according to claim 1 , wherein the metal layer is an aluminum foil or a copper foil.

11. A secondary battery, comprising:

a positive electrode;

a negative electrode;

an electrolyte; and

a separator, wherein

at least one of the positive electrode and the negative electrode comprises the current collector according to claim 1 .

12. A battery module, comprising the secondary battery according to claim 11 .

13. A battery pack, comprising the battery module according to claim 12 .