US 11,862,812 B2
Composite separator including porous substrate with porous layer including polyacrylic acid metal salt binder and inorganic particles, lithium battery including the same, and method of preparing the same
Minho Cho, Yongin-si (KR); Byungmin Lee, Yongin-si (KR); Kyoseon Koo, Yongin-si (KR); and Esul Jung, Yongin-si (KR)
Assigned to Samsung SDI Co., Ltd., Yongin-si (KR)
Filed by Samsung SDI Co., Ltd., Yongin-si (KR)
Filed on Mar. 23, 2021, as Appl. No. 17/209,692.
Claims priority of application No. 10-2020-0035811 (KR), filed on Mar. 24, 2020.
Prior Publication US 2021/0305658 A1, Sep. 30, 2021
Int. Cl. H01M 50/446 (2021.01); H01M 50/449 (2021.01); H01M 50/42 (2021.01); H01M 10/0525 (2010.01); H01M 50/489 (2021.01); H01M 50/403 (2021.01); H01M 50/431 (2021.01)
CPC H01M 50/446 (2021.01) [H01M 10/0525 (2013.01); H01M 50/403 (2021.01); H01M 50/42 (2021.01); H01M 50/431 (2021.01); H01M 50/449 (2021.01); H01M 50/489 (2021.01)] 17 Claims
OG exemplary drawing
 
1. A composite separator comprising:
a porous substrate; and
a coating layer on at least one surface of the porous substrate,
wherein the coating layer comprises a water-soluble binder and inorganic particles,
the water-soluble binder comprises a polyacrylic acid metal salt,
the polyacrylic acid metal salt has a weight average molecular weight of 300,000 Dalton to 450,000 Dalton, and
the inorganic particles have an average particle diameter (D50) of about 500 nm or more,
wherein the polyacrylic acid metal salt comprises a polyacrylic acid lithium salt, and
wherein the polyacrylic acid metal salt comprises an acrylic acid repeating unit substituted with lithium ions and an acrylic acid repeating unit, and a mole ratio of the acrylic acid repeating unit substituted with lithium ions to the acrylic acid repeating unit included the polyacrylic acid metal salt is from about 0.3 to about 0.9.