| CPC H01M 50/446 (2021.01) [H01M 8/0202 (2013.01); H01M 10/0525 (2013.01); H01M 50/417 (2021.01); H01M 50/42 (2021.01); H01M 50/451 (2021.01); H01M 50/454 (2021.01); H01M 50/457 (2021.01); H01M 50/461 (2021.01); H01M 50/489 (2021.01); H01M 2004/027 (2013.01); H01M 2004/028 (2013.01); H01M 50/411 (2021.01); H01M 50/431 (2021.01); H01M 50/434 (2021.01); H01M 50/443 (2021.01)] | 15 Claims |

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1. A separator for a rechargeable lithium battery, the separator comprising:
a porous substrate, and
a coating layer on at least one surface of the porous substrate,
wherein:
the coating layer includes:
a heat resistant binder including a (meth)acryl copolymer including a first structural unit and a second structural unit, the first structural unit being a structural unit of a (meth)acrylamide in an amount of 90 mol % to 95 mol %, and the second structural unit being a structural unit of a (meth)acrylamido sulfonic acid, a (meth)acrylamido sulfonate salt, or a combination thereof in an amount of 5 mol % to 10 mol %, and a (meth)acrylic acid, a (meth)acrylate, a (meth)acrylonitrile, or combination thereof in an amount of 0 mol % to 10 mol %, based on 100 mol % of the (meth)acryl copolymer;
polyethylene particles; and
first inorganic particles,
an average particle size (D50) of the first inorganic particles is larger than an average particle size (D50) of the polyethylene particles,
a weight ratio of the first inorganic particles and the polyethylene particles is 50:50 to 1:99,
the average particle size (D50) of the first inorganic particles is 1.0 μm to 1.5 μm, and
the average particle size (D50) of the polyethylene particles is 0.7 μm or more and less than 1.0 μm.
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