US 12,237,537 B2
Separator including polymer substrate with porous coating layer containing PVDF-based binder having β-phase and -phase crystals, and lithium secondary battery including the same
Joo-Sung Lee, Daejeon (KR); Bong-Tae Kim, Daejeon (KR); and Kil-An Jung, Daejeon (KR)
Assigned to LG Chem, Ltd., Seoul (KR)
Appl. No. 17/629,169
Filed by LG Chem, Ltd., Seoul (KR)
PCT Filed Aug. 7, 2020, PCT No. PCT/KR2020/010508
§ 371(c)(1), (2) Date Jan. 21, 2022,
PCT Pub. No. WO2021/029629, PCT Pub. Date Feb. 18, 2021.
Claims priority of application No. 10-2019-0099817 (KR), filed on Aug. 14, 2019.
Prior Publication US 2022/0255189 A1, Aug. 11, 2022
Int. Cl. H01M 50/449 (2021.01); H01M 10/0525 (2010.01); H01M 50/446 (2021.01); H01M 50/46 (2021.01)
CPC H01M 50/449 (2021.01) [H01M 10/0525 (2013.01); H01M 50/446 (2021.01); H01M 50/46 (2021.01)] 14 Claims
OG exemplary drawing
 
1. A separator for a lithium secondary battery comprising:
a porous polymer substrate; and
a porous coating layer positioned on at least one surface of the porous polymer substrate, the porous coating layer comprising inorganic particles and a binder polymer, wherein the binder polymer comprises a PVdF-based binder polymer, and the PVdF-based binder polymer has a first peak at a 2θ of 18.2±0.2° and a second peak at a 2θ of 19.8±0.2°, as analyzed by X-ray diffractometry, and a ratio of an area of the second peak to an area of the first peak is equal to or more than 1.25 and less than 2.75,
wherein the PVdF-based binder polymer comprises a first PVdF-based binder polymer and a second PVdF-based binder polymer, wherein the second PVdF-based binder polymer is different from the first PVdF-based binder polymer.