Negative electrode active material for power storage device
Provided is a negative electrode active material for a power storage device that has a low operating potential, can increase the operating voltage of the power storage device, and has excellent cycle characteristics. The negative electrode active material for a power storage device, the negative electrode active material containing as elements at least one selected from Si, B, and P; Nb; and O.
1. A negative electrode active material for a power storage device, the negative electrode active material containing as elements at least one selected from Si, B, P, and Al; Nb; and O;
the negative electrode active material containing, in terms of % by mole of oxide, 18 to 90% Nb 2 O 5 , and 5 to 85% SiO 2 +B 2 O 3 +P 2 O 5 +Al 2 O 3 ;
the negative electrode active material containing an amorphous phase;
the negative electrode active material has a structure in which Nb ions as an active material component are dispersed in an oxide matrix containing Si, B, P, or Al; and
the negative electrode active material is made of a glass or a crystallized glass.
2. The negative electrode active material for the power storage device according to claim 1 , the negative electrode active material further containing, in terms of % by mole of oxide, 1 to 70% R 2 O+R′O (where R represents at least one selected from Li, Na, and K and R′ represents at least one selected from Mg, Ca, Ba, Zn, and Sr).
3. The negative electrode active material for the power storage device according to claim 2 , wherein R 2 O is Na 2 O.
4. The negative electrode active material for the power storage device according to claim 1 , wherein the negative electrode active material is for use in a sodium-ion secondary battery.
5. A negative electrode material for the power storage device, the negative electrode material containing the negative electrode active material according to claim 1 .
6. A negative electrode for the power storage device, the negative electrode containing the negative electrode material according to claim 5 .
7. The power storage device comprising the negative electrode according to claim 6 .