US 11,735,709 B2
Positive electrode for lithium secondary battery, preparation method thereof, and lithium secondary battery including same
Ji Won Min, Daejeon (KR); Seok Koo Kim, Daejeon (KR); Youngsik Kim, Ulsan (KR); Janis Doelle, Daejeon (KR); Seongwoo Heo, Ulsan (KR); and Youngjun Lim, Ulsan (KR)
Assigned to UNIST (Ulsan National Institute of Science and Technology); and LG Energy Solution, Ltd.
Appl. No. 16/629,234
Filed by LG Chem, Ltd., Seoul (KR); and UNIST (Ulsan National Institute of Science and Technology), Ulsan (KR)
PCT Filed Jul. 9, 2018, PCT No. PCT/KR2018/007766
§ 371(c)(1), (2) Date Jan. 7, 2020,
PCT Pub. No. WO2019/013511, PCT Pub. Date Jan. 17, 2019.
Claims priority of application No. 10-2017-0087275 (KR), filed on Jul. 10, 2017.
Prior Publication US 2020/0227724 A1, Jul. 16, 2020
Int. Cl. H01M 4/04 (2006.01); H01M 4/131 (2010.01); H01M 4/1391 (2010.01); H01M 4/505 (2010.01); H01M 4/525 (2010.01); H01M 4/62 (2006.01); H01M 10/0525 (2010.01); H01M 4/02 (2006.01)
CPC H01M 4/131 (2013.01) [H01M 4/0404 (2013.01); H01M 4/0435 (2013.01); H01M 4/1391 (2013.01); H01M 4/505 (2013.01); H01M 4/525 (2013.01); H01M 4/62 (2013.01); H01M 10/0525 (2013.01); H01M 2004/028 (2013.01)] 11 Claims
 
1. A lithium secondary battery, comprising,
a positive electrode;
a negative electrode; and
a separator interposed between the positive electrode and the negative electrode;
wherein the positive electrode comprises a positive electrode mixture layer disposed on a positive electrode current collector, wherein
the positive electrode mixture layer includes a positive electrode active material and a lithium ion additive,
the lithium ion additive is a lithium ion conductive ceramic material represented by Formula 2 below, and
the lithium ion conductive ceramic material has a structure in which lithium ions are additionally inserted into vacancy sites of a NASICON-type (Na super ionic conductors-type) structure,
wherein the lithium ion additive acts as an effective irreversible additive at a charge/discharge voltage range of 3.0 V to 4.5 V,
wherein the positive electrode active material and the lithium ion additive are included in a weight ratio of 8.5:1.5 to 9:1,
wherein the positive electrode active material includes lithium cobalt oxide (LiCoO2): and wherein a capacity retention rate after 30 cycles is 92.1-97.5%
Li1+x2+y2Ti2−x2Alx2(PO4)3  [Formula 2]
in Formula 2, 0<x2≤0.3, and 1.7≤y2≤2.0.