Negative electrode active material, negative electrode and battery
View Patent ↗Provided is a negative electrode active material that can improve the discharge capacity per volume and/or charge-discharge cycle characteristics. The negative electrode active material according to the present embodiment contains an alloy phase and ceramics. The alloy phase undergoes thermoelastic diffusionless transformation when releasing or occluding metal ions. The ceramics is dispersed in the metal phase. The content of ceramics in the alloy phase is more than 0 to 50 mass % with respect to the total mass of the alloy phase and the ceramics.
1. A negative electrode active material, comprising:
an alloy phase which undergoes thermoelastic diffusionless transformation when releasing metal ions or occluding the metal ions; and
ceramics included in and dispersed in the alloy phase, wherein
the content of the ceramics in the alloy phase is more than 0 to 50 mass % with respect to a total mass of the alloy phase and the ceramics.
2. The negative electrode active material according to claim 1 , wherein
the ceramics contains one or more kinds selected from the group consisting of Al 2 O 3 , FeSi, SiC, Si 3 N 4 , TiC, TiB 2 , Y 2 O 3 , ZrB 2 , HfB 2 , ZrO 2 , ZnO, WC, W 2 C, CrB 2 , BN, and CeO 2 .
3. The negative electrode active material according to claim 2 , wherein
the alloy phase undergoes thermoelastic diffusionless transformation when occluding the metal ions, and undergoes reverse transformation when releasing the metal ions.
4. The negative electrode active material according to claim 3 , wherein
the alloy phase after the thermoelastic diffusionless transformation contains a crystal structure which is 2H in Ramsdell notation, and
the alloy phase after the reverse transformation contains a crystal structure which is D0 3 in Strukturbericht notation.
5. The negative electrode active material according to claim 4 , wherein
the alloy phase contains Cu and Sn.
6. The negative electrode active material according to claim 5 , wherein
the alloy phase contains 10 to 20 at % or 21 to 27 at % of Sn, with the balance being Cu and impurities.
7. The negative electrode active material according to claim 5 , wherein
the alloy phase further contains, in place of a part of Cu, one or more kinds selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Al, Si, B, and C.
8. The negative electrode active material according to claim 7 , wherein
the alloy phase contains:
Sn: 10 to 35 at %; and
one or more kinds selected from the group consisting of Ti: 9.0 at % or less, V: 49.0 at % or less, Cr: 49.0 at % or less, Mn: 9.0 at % or less, Fe: 49.0 at % or less, Co: 49.0 at % or less, Ni: 9.0 at % or less, Zn: 29.0 at % or less, Al: 49.0 at % or less, Si: 49.0 at % or less, B: 5.0 at % or less, and C: 5.0 at % or less,
with the balance being Cu and impurities.
9. The negative electrode active material according to claim 3 , wherein
the alloy phase contains Cu and Sn.
10. The negative electrode active material according to claim 9 , wherein
the alloy phase contains 10 to 20 at % or 21 to 27 at % of Sn, with the balance being Cu and impurities.
11. The negative electrode active material according to claim 9 , wherein
the alloy phase further contains, in place of a part of Cu, one or more kinds selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Al, Si, B, and C.
12. The negative electrode active material according to claim 11 , wherein
the alloy phase contains:
Sn: 10 to 35 at %; and
one or more kinds selected from the group consisting of Ti: 9.0 at % or less, V: 49.0 at % or less, Cr: 49.0 at % or less, Mn: 9.0 at % or less, Fe: 49.0 at % or less, Co: 49.0 at % or less, Ni: 9.0 at % or less, Zn: 29.0 at % or less, Al: 49.0 at % or less, Si: 49.0 at % or less, B: 5.0 at % or less, and C: 5.0 at % or less,
with the balance being Cu and impurities.
13. The negative electrode active material according to claim 1 , wherein
the alloy phase undergoes thermoelastic diffusionless transformation when occluding the metal ions, and undergoes reverse transformation when releasing the metal ions.
14. The negative electrode active material according to claim 13 , wherein
the alloy phase after the thermoelastic diffusionless transformation contains a crystal structure which is 2H in Ramsdell notation, and
the alloy phase after the reverse transformation contains a crystal structure which is D0 3 in Strukturbericht notation.
15. The negative electrode active material according to claim 14 , wherein
the alloy phase contains Cu and Sn.
16. The negative electrode active material according to claim 15 , wherein
the alloy phase contains 10 to 20 at % or 21 to 27 at % of Sn, with the balance being Cu and impurities.
17. The negative electrode active material according to claim 15 , wherein
the alloy phase further contains, in place of a part of Cu, one or more kinds selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Al, Si, B, and C.
18. The negative electrode active material according to claim 17 , wherein
the alloy phase contains:
Sn: 10 to 35 at %; and
one or more kinds selected from the group consisting of Ti: 9.0 at % or less, V: 49.0 at % or less, Cr: 49.0 at % or less, Mn: 9.0 at % or less, Fe: 49.0 at % or less, Co: 49.0 at % or less, Ni: 9.0 at % or less, Zn: 29.0 at % or less, Al: 49.0 at % or less, Si: 49.0 at % or less, B: 5.0 at % or less, and C: 5.0 at % or less,
with the balance being Cu and impurities.
19. The negative electrode active material according to claim 13 , wherein
the alloy phase contains Cu and Sn.
20. The negative electrode active material according to claim 19 , wherein
the alloy phase contains 10 to 20 at % or 21 to 27 at % of Sn, with the balance being Cu and impurities.
21. The negative electrode active material according to claim 19 , wherein
the alloy phase further contains, in place of a part of Cu, one or more kinds selected from the group consisting of Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Al, Si, B, and C.
22. The negative electrode active material according to claim 21 , wherein
the alloy phase contains:
Sn: 10 to 35 at %; and
one or more kinds selected from the group consisting of Ti: 9.0 at % or less, V: 49.0 at % or less, Cr: 49.0 at % or less, Mn: 9.0 at % or less, Fe: 49.0 at % or less, Co: 49.0 at % or less, Ni: 9.0 at % or less, Zn: 29.0 at % or less, Al: 49.0 at % or less, Si: 49.0 at % or less, B: 5.0 at % or less, and C: 5.0 at % or less,
with the balance being Cu and impurities.
23. A negative electrode, comprising the negative electrode active material according to claim 1 .
24. A battery, comprising the negative electrode according to claim 23 .