Disclosed are positive electrode active materials for a rechargeable lithium battery and positive electrodes including the positive electrode active materials. The positive electrode active material comprises first particles comprising a compound having an olivine structure, second particles having a spinel structure, and third particles having a layered structure. The amount of the third particles is about 10 parts by weight to about 50 parts by weight based on 100 parts by weight of the positive electrode active material.

Disclosed are positive electrode active materials for a rechargeable lithium battery and positive electrodes including the positive electrode active materials. The positive electrode active material comprises first particles comprising a compound having an olivine structure, second particles having a spinel structure, and third particles having a layered structure. The amount of the third particles is about 10 parts by weight to about 50 parts by weight based on 100 parts by weight of the positive electrode active material.

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 CuK ray, a peak having a half width of 0.5 to 5 is observed within a range of 40 to 45.

##STR00001## (In the formula (1), 1.1<x2.8, 0.8a<1.9, 0.05<b0.6, 1.0a+b<2.0, 0c<0.2, 0d<1.0, 0e<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.)

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 CuK ray, a peak having a half width of 0.5 to 5 is observed within a range of 40 to 45.

##STR00001## (In the formula (1), 1.1<x2.8, 0.8a<1.9, 0.05<b0.6, 1.0a+b<2.0, 0c<0.2, 0d<1.0, 0e<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.)

Provided is a method for producing a lithium-containing solution that allows suppressing production cost for lithium production by increasing a lithium content rate in a solution after an eluting step, and suppressing amount of a solution used in a process after the eluting step. The method for producing a lithium-containing solution includes an adsorption step, an eluting step of bringing post-adsorption lithium manganese oxide into contact with an acid-containing solution to obtain an eluted solution, and a manganese oxidation step performed in this order. The eluted solution is separated into a high concentration lithium-eluted solution and a low concentration lithium-eluted solution. The acid-containing solution includes a solution prepared by adding acid to the low concentration lithium-eluted solution. With this aspect, since only the low concentration lithium-eluted solution is added to the acid-containing solution, a hydrogen ion concentration in the acid-containing solution can be increased by adding just a small amount of acid, which consequently allows suppressing amount of the acid-containing solution and allows suppressing amount of the eluted solution used in the manganese oxidation step.

Provided is a method for producing a lithium-containing solution that allows suppressing production cost for lithium production by increasing a lithium content rate in a solution after an eluting step, and suppressing amount of a solution used in a process after the eluting step. The method for producing a lithium-containing solution includes an adsorption step, an eluting step of bringing post-adsorption lithium manganese oxide into contact with an acid-containing solution to obtain an eluted solution, and a manganese oxidation step performed in this order. The eluted solution is separated into a high concentration lithium-eluted solution and a low concentration lithium-eluted solution. The acid-containing solution includes a solution prepared by adding acid to the low concentration lithium-eluted solution. With this aspect, since only the low concentration lithium-eluted solution is added to the acid-containing solution, a hydrogen ion concentration in the acid-containing solution can be increased by adding just a small amount of acid, which consequently allows suppressing amount of the acid-containing solution and allows suppressing amount of the eluted solution used in the manganese oxidation step.