US 12,255,328 B2
Negative electrode material for lithium ion battery
Suguru Ikeda, Hiroshima (JP); Hiroki Fujita, Hiroshima (JP); and Hackho Kim, Fukuoka (JP)
Assigned to MAZDA MOTOR CORPORATION, Hiroshima (JP)
Filed by MAZDA MOTOR CORPORATION, Hiroshima (JP)
Filed on Jan. 25, 2022, as Appl. No. 17/583,389.
Claims priority of application No. 2021-035146 (JP), filed on Mar. 5, 2021.
Prior Publication US 2022/0285677 A1, Sep. 8, 2022
Int. Cl. H01M 4/525 (2010.01); H01M 4/02 (2006.01); H01M 4/36 (2006.01)
CPC H01M 4/525 (2013.01) [H01M 4/364 (2013.01); H01M 2004/021 (2013.01); H01M 2004/027 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A negative electrode material for a lithium ion secondary battery, the negative electrode material comprising
a mixture of a powder of a conversion-type oxide and a powder of an oxygen ion conductor, the conversion-type oxide being made of an iron oxide and/or a silicon oxide and absorbing and releasing Li ions through conversion reactions, wherein
the conversion-type oxide is made of magnetite and/or a silicon oxide SiO having an Si phase and an SiO2 phase,
the oxygen ion conductor is made of samarium-doped ceria,
a proportion of the powder of the oxygen ion conductor in a total amount of the powder of the conversion-type oxide and the powder of the oxygen ion conductor is 3 mass % or more and 10 mass % or less, and
a rate of retention of a discharge capacity at a 30th cycle of the lithium ion secondary battery containing the negative electrode material comprising the mixture is higher than a rate of retention of a discharge capacity at a 30th cycle of a lithium ion secondary battery containing a negative electrode material including the powder of the conversion-type oxide without the powder of the oxygen ion conductor.