US 12,278,366 B2
Lithium cobalt aluminum oxide positive electrode active material including aluminum-containing coating film and secondary battery
Jyo Saito, Kanagawa (JP); Mayumi Mikami, Kanagawa (JP); Yohei Momma, Kanagawa (JP); Teruaki Ochiai, Kanagawa (JP); Tatsuyoshi Takahashi, Kanagawa (JP); and Kazuhei Narita, Tokyo (JP)
Assigned to Semiconductor Energy Laboratory Co., Ltd., Atsugi (JP)
Appl. No. 17/413,160
Filed by SEMICONDUCTOR ENERGY LABORATORY CO., LTD., Atsugi (JP)
PCT Filed Dec. 4, 2019, PCT No. PCT/IB2019/060418
§ 371(c)(1), (2) Date Jun. 11, 2021,
PCT Pub. No. WO2020/128699, PCT Pub. Date Jun. 25, 2020.
Claims priority of application No. 2018-235792 (JP), filed on Dec. 17, 2018; and application No. 2018-235801 (JP), filed on Dec. 17, 2018.
Prior Publication US 2022/0052335 A1, Feb. 17, 2022
Int. Cl. H01M 4/525 (2010.01); H01M 4/02 (2006.01); H01M 4/36 (2006.01); H01M 10/0525 (2010.01); H01M 10/0569 (2010.01)
CPC H01M 4/525 (2013.01) [H01M 4/366 (2013.01); H01M 10/0525 (2013.01); H01M 10/0569 (2013.01); H01M 2004/021 (2013.01); H01M 2004/028 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A positive electrode active material comprising:
a first particle group and a second particle group,
wherein the positive electrode active material has a crystal structure belonging to a space group R-3m,
wherein the crystal structure is estimated by Rietveld analysis of a pattern obtained by powder X-ray diffraction using a CuKα1 ray,
wherein the positive electrode active material comprises lithium cobalt oxide, magnesium, aluminum, and nickel,
wherein, in X-ray photoelectron spectroscopy of the positive electrode active material, a number of aluminum atoms is less than a number of magnesium atoms and greater than a number of nickel atoms,
wherein a particle size distribution of the first particle group has a first local maximum peak and a particle size distribution of the second particle group has a second local maximum peak,
wherein the first local maximum peak has a local maximum value at greater than or equal to 9 μm and less than or equal to 25 μm,
wherein the second local maximum peak has a local maximum value at greater than or equal to 0.1 μm and less than 9 μm,
wherein the first particle group comprises a first positive electrode active material particle comprising lithium cobalt oxide, magnesium, aluminum, and nickel,
wherein the second particle group comprises a second positive electrode active material particle comprising lithium cobalt oxide, aluminum, and nickel,
wherein, in any one of ICP-MS, GD-MS, and elementary analysis of atomic absorption, an atomic ratio of magnesium to cobalt in the first particle group is greater than or equal to 0.001 and less than or equal to 0.06, and
wherein the atomic ratio of magnesium to cobalt in the first particle group is higher than an atomic ratio of magnesium to cobalt in the second particle group.