Anode for lithium secondary battery and method for manufacturing same
Disclosed is an anode for a lithium secondary battery, and more particularly, an anode comprising a fibrillated binder and a particulate binder.
1 . An anode for a lithium secondary battery, comprising:
an active material comprising a carbon material;
a fibrillated binder; and
a particulate binder comprising at least one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), or any combination thereof,
wherein the anode comprises:
an amount of about 95% by weight to 97% by weight of the active material,
an amount of about 1% by weight to 4% by weight of the fibrillated binder, and
an amount of about 1% by weight to 2% by weight of the particulate binder.
2 . The anode of claim 1 , wherein the PTFE has an average particle size of about 0.1 μm to 500 μm.
3 . The anode of claim 1 , wherein the PTFE comprises a secondary particle including a plurality of primary particles.
4 . The anode of claim 1 , wherein the PTFE has a bulk density of about 350 g/l to 450 g/l.
5 . The anode of claim 1 , wherein the PTFE has a BET specific surface area of about 3 m 2 /g or less.
6 . The anode of claim 1 , wherein the PVDF has an average particle size of about 0.1 μm to 500 μm.
7 . The anode of claim 1 , wherein the PVDF includes a primary particle.
8 . The anode of claim 1 , wherein the PVDF has a melting point of about 170° C. or less.
9 . The anode of claim 1 , wherein the PVDF has a number-average molecular weight (Mn) of about 500,000 g/mol to 800,000 g/mol.
10 . The anode of claim 1 , wherein the PVDF has a weight-average molecular weight (Mw) of about 500,000 g/mol to 800,000 g/mol.
11 . The anode of claim 1 , wherein the particulate binder and the fibrillated binder have a weight ratio of about 1:4 to 1:1.5.
12 . A method for manufacturing the anode of claim 1 comprising:
preparing a mixture including the active material and the particulate binder;
mixing the mixture and a fibrillizable binder to obtain a particle composition, wherein the fibrillizable binder corresponds to a precursor to the fibrillated binder; and
applying heat and pressure to the particle composition to form a film.
13 . The method of claim 12 , wherein the mixture is prepared by dry-mixing the active material and the particulate binder without a solvent.
14 . The method of claim 12 , wherein the mixture is prepared by mixing the active material and the particulate binder at a temperature of about 30° C. or less for about 60 minutes or less at a speed of about 20 m/s to 30 m/s.
15 . The method of claim 12 , wherein the particle composition is obtained by mixing the mixture and the fibrillizable binder at a temperature of about 80° C. or less for about 60 minutes or less at a speed of about 20 m/s to 30 m/s.
16 . The method of claim 12 , wherein the particle composition has an average particle size of about 1 nm to 500 nm.
17 . The method of claim 12 , wherein the method comprises applying pressure of about 0.1 ton per square inch (TSI) to 12 TSI to the particle composition at a temperature of about 30° C. to 160° C. to form the film.