US 12,191,479 B2
Negative electrode active material, negative electrode, and secondary battery
Yasuhiro Ikeda, Kyoto (JP)
Assigned to Murata Manufacturing Co., Ltd., Kyoto (JP)
Filed by MURATA MANUFACTURING CO., LTD., Kyoto (JP)
Filed on Oct. 21, 2021, as Appl. No. 17/507,476.
Application 17/507,476 is a continuation of application No. PCT/JP2020/016015, filed on Apr. 9, 2020.
Claims priority of application No. 2019-086865 (JP), filed on Apr. 26, 2019.
Prior Publication US 2022/0045316 A1, Feb. 10, 2022
Int. Cl. H01M 4/36 (2006.01); H01M 4/38 (2006.01); H01M 4/587 (2010.01); H01M 10/0525 (2010.01); H01M 4/02 (2006.01)
CPC H01M 4/364 (2013.01) [H01M 4/386 (2013.01); H01M 4/587 (2013.01); H01M 2004/027 (2013.01); H01M 10/0525 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A negative electrode active material comprising:
a first negative electrode active material particle including a silicon-based material having a silicon surface forming charge state,
wherein a Si2p spectrum obtained by measuring the first negative electrode active material particle by X-ray photoelectron spectroscopy has a peak in a range from 99.0 eV to 105.0 eV,
wherein a half width of the peak is 1.5 eV or more and 8.0 eV or less,
wherein the peak corresponds to the silicon surface forming charge state of the first negative electrode active material particle in a charged state of 0.6 V (vs. Li/Li+), and
wherein the charged state of 0.6 V (vs. Li/Li+) is based on a constant current charge at 0.05 C, thereafter a constant voltage charge at 0.6 V until a current value is 0.005 C.