ALKALI METAL-CONTAINING OXIDE, POSITIVE ELECTRODE ACTIVE SUBSTANCE, ELECTRODE, AND BATTERY
An alkali metal-containing oxide of the present disclosure has a spinel structure and a composition represented by the following formula (1). In an X-ray diffraction chart measured at 25° C. using a CuKα ray, a peak having a half width of 0.5° to 5° is observed within a range of 40° to 45°. (In the formula (1), 1.1<x≤2.8, 0.8≤a<1.9, 0.05<b≤0.6, 1.0≤a+b<2.0, 0≤c<0.2, 0≤d<1.0, 0≤e<1.0, A is an alkali metal element, M′ is at least one element from Ti, Cr, Mn, Fe, Co, Ni and Cu, M″ is at least one from Si, P, S, Ge and V, Z is an element of Group II to Group XVI except oxygen, M′ and M″, and X is a halogen element.)
1 . An alkali metal-containing oxide having a spinel structure and having a composition represented by the following formula (1),
wherein, in an X-ray diffraction chart measured regarding the alkali metal-containing oxide at 25° C. using a CuKα ray, a peak having a half width of 0.5° to 5° at 2θ is observed within a range of 40° to 45° at 2θ,
(in the formula (1), 1.1<x≤2.8, 0.8≤a<1.9, 0.05<b≤0.6, 1.0≤a+b<2.0, 0≤c<0.2, 0≤d<1.0, 0≤e<1.0,
A is an alkali metal element,
M′ is at least one element selected from the group consisting of Ti, Cr, Mn, Fe, Co, Ni and Cu,
M″ is at least one selected from the group consisting of Si, P, S, Ge and V,
Z is an element of Group II to Group XVI in a periodic table except oxygen, M′ and M″, and
X is a halogen element).
2 . The alkali metal-containing oxide according to claim 1 ,
wherein, in a case where an electrochemical cell including an electrode containing the alkali metal-containing oxide, a lithium-metal auxiliary electrode and an electrolytic solution containing a lithium salt disposed between the electrode and the auxiliary electrode is produced, the electrochemical cell is charged up to 4.8 V based on Li/Li + , and discharging is then performed to 1.5 V, x in the formula (1) is within a range of 2.2 to 2.8.
3 . The alkali metal-containing oxide according to claim 1 ,
wherein, in the formula (1), A includes Li.
4 . The alkali metal-containing oxide according to claim 1 ,
wherein, in the formula (1), M″ includes V.
5 . The alkali metal-containing oxide according to claim 1 ,
wherein, in the formula (1), 1.1<x≤2.0 is satisfied.
6 . An electrode comprising:
the alkali metal-containing oxide according to claim 1 .
7 . A battery comprising:
the electrode according to claim 6 as a positive electrode; and
a negative electrode containing lithium.
8 . A positive electrode active substance comprising:
a composite oxide containing an alkali metal element, an element M′ and an element M″,
wherein 8 to 15 mass % of the alkali metal element is contained, 32 to 57 mass % of the element M′, which is at least one selected from the group consisting of Ti, Cr, Mn, Fe, Co, Ni and Cu, is contained, and 3 to 30 mass % of the element M″, which is at least one selected from the group consisting of Si, P, S, Ge and V, is contained, in an X-ray diffraction chart measured regarding the positive electrode active substance at 25° C. using a CuKα ray, a peak pattern belonging to the spinel structure derived from the composite oxide is observed, and a peak having a half width of 0.5° to 5° is observed within a range of 40° to 45° at 2θ.
9 . The alkali metal-containing oxide according to claim 1 , having an amorphous phase.