The cathode active material includes secondary particles. The secondary particle includes a plurality of crystallites. Each of the plurality of crystallites includes a lithium metal composite oxide. A structure of the lithium metal composite oxide is a layered-rocksalt structure. In the cross section of the secondary particle, 2.5d.sub.L/d.sub.S28.2, 0.125d.sub.L/D, and 450 are satisfied. d.sub.L indicates the major axis diameter of the crystallite. d.sub.S indicates the minor axis diameter of the crystallite. D indicates the maximum Feret diameter of the secondary particles. represents an angle formed between the first straight line and the second straight line. The first straight line is an extension of the major axis diameter of the crystallite. The second straight line passes through the intersection of the circumscribed circle of the secondary particle and the extension line and the center of the circumscribed circle.

A method for recovering lithium from a stream containing lithium. The method includes the step of contacting the stream, or a pre-treated solution obtained from the stream, with an aluminium-containing material to form a precipitate including lithium aluminate, at an alkaline pH. The method further includes the step of recovering a slurry of the lithium aluminate.

A method for recovering lithium from a stream containing lithium. The method includes the step of contacting the stream, or a pre-treated solution obtained from the stream, with an aluminium-containing material to form a precipitate including lithium aluminate, at an alkaline pH. The method further includes the step of recovering a slurry of the lithium aluminate.