US 12,381,202 B2
Anode for lithium secondary battery, method of manufacturing the same and lithium secondary battery including the same
Kwang Ho Jeong, Daejeon (KR); Seung Deok Seo, Daejeon (KR); and Ji Sun Lee, Daejeon (KR)
Assigned to SK ON CO., LTD., Seoul (KR); and SK INNOVATION CO., LTD., Seoul (KR)
Filed by SK ON CO., LTD., Seoul (KR); and SK INNOVATION CO., LTD., Seoul (KR)
Filed on Dec. 5, 2023, as Appl. No. 18/528,787.
Claims priority of application No. 10-2022-0177963 (KR), filed on Dec. 19, 2022.
Prior Publication US 2024/0213446 A1, Jun. 27, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. H01M 4/134 (2010.01); H01M 4/133 (2010.01); H01M 4/1393 (2010.01); H01M 4/1395 (2010.01); H01M 4/36 (2006.01); H01M 4/48 (2010.01); H01M 4/587 (2010.01); H01M 4/62 (2006.01); H01M 10/0525 (2010.01); H01M 10/42 (2006.01); H01M 4/02 (2006.01); H01M 4/04 (2006.01)
CPC H01M 4/134 (2013.01) [H01M 4/133 (2013.01); H01M 4/1393 (2013.01); H01M 4/1395 (2013.01); H01M 4/364 (2013.01); H01M 4/366 (2013.01); H01M 4/483 (2013.01); H01M 4/587 (2013.01); H01M 4/622 (2013.01); H01M 4/625 (2013.01); H01M 10/0525 (2013.01); H01M 10/4235 (2013.01); H01M 2004/027 (2013.01); H01M 4/0404 (2013.01); H01M 4/0471 (2013.01)] 5 Claims
 
1. A charged and discharged lithium secondary battery, comprises:
an anode for a lithium secondary battery, a cathode facing the anode and an electrolyte comprising LiPF6,
wherein the anode comprises:
an anode current collector; and
an anode active material layer on at least one surface of the anode current collector, the anode active material layer including an anode active material and an anode binder including a polyacrylic acid-based copolymer,
wherein the anode active material comprises a composite particle that includes a silicon-based active material particle and a solid electrolyte interphase (SEI) layer formed on at least a portion of a surface of the silicon-based active material particle, wherein the SEI layer includes LiF, and
an F-density defined by Equation 1 is from 0% to 23%:

OG Complex Work Unit Math
wherein, in Equation 1, FC is an area of a portion where an F-intensity obtained by scanning a cross-sectional image of the anode active material layer from a scanning electron microscope-energy dispersion X-ray spectroscopy (SEM-EDS) analysis after a formation charging and discharging of the battery with a fluorine (F) element is from 60% to 100%, and
FT is a total area from which the F element obtained by scanning the cross-sectional image of the anode active material layer from the SEM-EDS analysis after a formation charging and discharging of the battery with the F element is detected, and
a ratio of the number of moles of repeating units derived from a polyacrylic acid to the total number of moles of repeating units included in one molecule of the polyacrylic acid-based copolymer is greater than 0.25 and less than 0.7, wherein the polyacrylic acid-based copolymer includes a polyacrylic acid-polyvinyl alcohol copolymer,
wherein the F-density defined by Equation 1 is measured on a range of 80 μm×50 μm in the cross-section of the anode active material layer, the F-density values is measured through the SEM-EDS analysis with respect to nine different points of the anode active material layer, an average of the F density values is calculated by summing all nine measured F density values and dividing them by 9, three of the nine different points of the anode active material layer is selected at one end portion in a length direction of the anode active material layer, another three of the nine different points of the anode active material layer is selected at the other end portion in the length direction of the anode active material layer, and the other three of the nine different points of the anode active material layer is selected at a central portion in the length direction of the anode active material layer.