CPC H01M 50/426 (2021.01) [C09D 7/45 (2018.01); C09D 7/61 (2018.01); C09D 7/65 (2018.01); C09D 127/16 (2013.01); H01M 10/052 (2013.01); H01M 50/417 (2021.01); H01M 50/42 (2021.01); H01M 50/423 (2021.01); H01M 50/429 (2021.01); H01M 50/44 (2021.01); H01M 50/446 (2021.01); H01M 50/451 (2021.01); H01M 50/454 (2021.01); H01M 50/457 (2021.01); H01M 10/0525 (2013.01)] | 13 Claims |
1. A coating composition, comprising:
a solvent, inorganic particles, a dispersant, and a binder,
wherein the binder comprises a binder B and a binder A,
both the binder B and the binder A comprise a vinylidene fluoride (VDF)-derived unit and a hexafluoropropylene (HFP)-derived unit,
binder B comprises 8 to 50 wt % of the HFP-derived unit, and binder A comprises 5 wt % or more of the HFP-derived unit under a condition that a proportion of the HFP-derived unit in the binder A is 80% or less of a proportion of the HFP-derived unit in the binder B,
the binder B has a total number average molecular weight of 200,000 to 2,000,000 Da, and the binder A has a total number average molecular weight corresponding to 70% or less of that of the binder B, and
a weight ratio of the binder A:the binder B in the coating composition is 0.8 to 2:1,
said coating composition being suitable for use in coating at least one surface of a porous substrate having a plurality of pores to form a coating layer, and
wherein the coating layer has a thickness of 3 μm or less on a cross-sectional basis,
wherein a larger amount of binder A is distributed on a surface of the coating layer compared to an amount of binder B distributed on the surface of the coating layer, and a larger amount of binder B is distributed inside the coating layer compared to an amount of binder A distributed inside the coating layer.
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