Active material, electrode, secondary battery, battery pack, and vehicle
According to one embodiment, an active material is provided. The active material includes a lithium niobium composite oxide represented by a general formula Li x Fe 1−y M1 y Nb 11−2 M2 z O 29 (1) and having an orthorhombic crystal structure. In the general formula (1), 0≤x≤23, 0≤y≤1 and 0<z≤6 are satisfied. Each of M1 and M2 independently includes at least one element selected from a group consisting of Fe, Mg, Al, Cu, Mn, Co, Ni, Zn, Sn, Ti, Ta, V, and Mo.
1. An active material comprising a lithium niobium composite oxide represented by a general formula Li x Fe 1−y M1,Nb 11−z M2 z O 29 (1) and having an orthorhombic crystal structure,
wherein in the general formula (1), 0≤x≤23, 0≤y≤1 and 0<z≤3.0 are satisfied and each of M1 and M2 independently comprises at least one element selected from a group consisting of Fe, Mg, Al, Cu, Mn, Co, Ni, Zn, Sn, Ti, Ta, V, and Mo.
2. The active material according to claim 1 , wherein in the general formula (1), 0<y≤1 is satisfied.
3. The active material according to claim 1 , wherein the M2 comprises elements selected from the group consisting of Fe, Mg, Al, Cu, Mn, Co, Ni, Zn, Sn, Ti, Ta, V, and Mo, and the elements have mutually different valence numbers.
4. The active material according to claim 1 , wherein the M1 comprises elements selected from the group consisting of Fe, Mg, Al, Cu, Mn, Co, Ni, Zn, Sn, Ti, Ta, V, and Mo, and the elements have mutually different valence numbers.
5. The active material according to claim 1 , wherein at least one of the M1 and the M2 comprises at least one element selected from a group consisting of Ti, V, and Sn.
6. The active material according to claim 1 , wherein the lithium niobium composite oxide has a crystal system of a space group represented by Amma.
7. An electrode comprising the active material according to claim 1 .
8. The electrode according to claim 7 , which comprises an active material-containing layer comprising the active material.
9. A secondary battery comprising:
a positive electrode;
a negative electrode; and
an electrolyte, wherein
the negative electrode is the electrode according to claim 7 .
10. A battery pack comprising the secondary battery according to claim 9 .
11. The battery pack according to claim 10 , further comprising:
an external power distribution terminal; and
a protective circuit.
12. The battery pack according to claim 10 , comprising plural of the secondary battery, wherein the secondary batteries are electrically connected in series, in parallel, or in a combination of series connection and parallel connection.
13. A vehicle comprising the battery pack according to claim 10 .
14. The vehicle according to claim 13 , which comprises a mechanism configured to convert kinetic energy of the vehicle into regenerative energy.