Method of manufacturing electrode-separator composite, electrode-separator composite manufactured by the manufacturing method and lithium secondary battery comprising the same
Disclosed is a method of manufacturing an electrode-separator composite: including (S1) coating an electrode active material slurry on at least one surface of an electrode current collector and drying to form an electrode, (S2) coating a polymer solution containing polymer particles on at least one surface of the electrode to form a separator coating layer, and (S3) drying the separator coating layer to form a porous separator, and an electrode-separator composite manufactured by the manufacturing method and a lithium secondary battery comprising the same. According to the present disclosure, a porous separator is manufactured by coating polymer particles on an electrode, thereby effectively controlling the uniformity and tortuosity of the pores, a porous separator is manufactured by directly coating a polymer solution on an electrode without separately manufacturing a separator, thereby saving the process costs and time, and further, when a functional group able to capture manganese is attached to the surface of polymer particles constituting a separator, deterioration in battery performance may be prevented through removal of manganese ions that may be deposited on an anode during operation of a battery.
1. An electrode-separator composite manufactured by a method comprising:
(S1) coating an electrode active material slurry on at least one surface of an electrode current collector and drying to form an electrode;
(S2) coating a solvent in which polymer particles are dispersed on at least one surface of the electrode to form a separator coating layer; and
(S3) drying the separator coating layer to form a porous separator containing the polymer particles, and
wherein the polymer particles include a mixture of first polymer particles with a particle size from 100 nm to 300 nm and second polymer particles with a particle size from 500 nm to 1,000 nm at a weight ratio between 2:8 and 3:7,
wherein in the separator coating layer the first polymer particles are uniformly arranged between the second polymer particles and the separator-coating layer has uniform tortuosity.
2. The electrode-separator composite according to claim 1 , wherein the polymer particles are an anionic polyelectrolyte, and wherein the anionic polyelectrolyte is selected from the group consisting of polystyrene sulfonate (PSS) and hyaluronic acid (HA).
3. An electrode-separator composite comprising:
an electrode including an electrode current collector and an electrode active material layer formed on at least one surface of the electrode current collector; and
a porous separator containing polymer particles formed on at least one surface of the electrode and obtained by drying a separator coating layer containing the polymer particles, wherein the polymer particles include a mixture of first polymer particles with a particle size from 100 nm to 300 nm and second polymer particles with a particle size from 500 nm to 1,000 nm at a weight ratio between 2:8 and 3:7,
wherein in the separator coating layer the first polymer particles are uniformly arranged between the second polymer particles and the separator-coating layer has uniform tortuosity.
4. The electrode-separator composite according to claim 3 , wherein the polymer particles are an anionic polyelectrolyte.
5. The electrode-separator composite according to claim 4 , wherein the anionic polyelectrolyte is selected from the group consisting of polystyrene sulfonate (PSS) and hyaluronic acid (HA).
6. The electrode-separator composite according to claim 3 , wherein the polymer particles include any one selected from the group consisting of polymethylmethacrylate, polystyrene, a copolymer containing methylmethacrylate as a monomer and a copolymer containing styrene as a monomer, or mixtures thereof.
7. The electrode-separator composite according to claim 3 , wherein a size of the polymer particles is from 100 nm to 1 μm.
8. The electrode-separator composite according to claim 3 , wherein the polymer particles have a functional group able to capture manganese attached onto the surface thereof.
9. The electrode-separator composite according to claim 3 , wherein the separator coating layer further contains a binder.
10. The electrode-separator composite according to claim 3 , wherein a size of pores formed in the porous separator is from 50 nm to 500 nm.
11. A lithium secondary battery comprising the electrode-separator composite defined in claim 3 .