US 9,812,707 B2
Carbon-coated lithium iron phosphate of olivine crystal structure and lithium secondary battery using the same
Hyun Kuk Noh, Daejeon (KR); Hong Kyu Park, Daejeon (KR); Cheol-Hee Park, Daejeon (KR); Su-min Park, Daejeon (KR); and JiEun Lee, Daejeon (KR)
Assigned to LG CHEM, LTD., Seoul (KR)
Filed by LG CHEM, LTD., Seoul (KR)
Filed on Apr. 11, 2014, as Appl. No. 14/251,333.
Application 14/251,333 is a continuation of application No. 13/623,458, filed on Sep. 20, 2012, granted, now 8,734,676.
Application 13/623,458 is a continuation of application No. PCT/KR2011/002876, filed on Apr. 21, 2011.
Claims priority of application No. 10-2010-0037079 (KR), filed on Apr. 21, 2010.
Prior Publication US 2014/0220445 A1, Aug. 7, 2014
This patent is subject to a terminal disclaimer.
Int. Cl. H01M 4/36 (2006.01); H01M 4/04 (2006.01); C01B 25/45 (2006.01); C01B 25/30 (2006.01); C01B 25/26 (2006.01); H01M 4/58 (2010.01); H01M 4/1397 (2010.01)
CPC H01M 4/366 (2013.01) [C01B 25/26 (2013.01); C01B 25/30 (2013.01); C01B 25/45 (2013.01); H01M 4/0416 (2013.01); H01M 4/5825 (2013.01); H01M 4/1397 (2013.01); Y02E 60/122 (2013.01); Y02P 70/54 (2015.11)] 15 Claims
 
1. Lithium iron phosphate having an olivine crystal structure, wherein the lithium iron phosphate has a composition represented by the following Formula 1 and carbon (C) is coated on the particle surface of the lithium iron phosphate containing a predetermined amount of sulfur (S):
Li1+aFe1−xMx(PO4−b)Xb  (1)
wherein
M is at least one selected from Al, Mg, Ni, Co, Mn, Ti, Ga, Cu, V, Nb, Zr, Ce, In, Zn and Y,
X is at least one selected from F, S and N, and
−0.5≤a≤+0.5, 0≤x≤0.5, 0≤b≤0.1
wherein the sulfur (S) is contained at an amount of 0.1 to 2% by weight, based on the total weight of the lithium iron phosphate, wherein the sulfur (S) is derived from a precursor for preparation of the lithium iron phosphate, and
wherein the sulfur and the carbon are present in the form of a structure in which carbon is coated on the surface of lithium iron phosphate particles and the sulfur is contained inside of lithium iron phosphate particles.