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Abstract

The present invention includes lithium cobalt oxides having hexagonal layered crystal structures and methods of making same. The lithium cobalt oxides of the invention have the formula Li.sub.w Co.sub.1-x A.sub.x O.sub.2+y wherein 0.96.ltoreq.w.ltoreq.1.05, 0.ltoreq.x.ltoreq.0.05, -0.02.ltoreq.y.ltoreq.0.02 and A is one or more dopants. The lithium cobalt oxides of the invention preferably have a position within the principal component space defined by the relationship ax.sub.i +by.sub.i.ltoreq.c, wherein x.sub.i =S.sub.i.circle-solid.P.sub.c1 ; y.sub.i =S.sub.i.circle-solid.P.sub.c2 ; the vector S.sub.i is the x-ray spectrum for the Li.sub.w Co.sub.1-x A.sub.x O.sub.2+y compound; the vectors P.sub.c1 and P.sub.c2 defining the principal component space are determined by measuring the x-ray powder diffraction values S.sub.i between 15.degree. and 120.degree. using a 0.02.degree. step size and CuK.alpha. rays for a large sample set of lithium cobalt oxides and using the regression of S.sub.i of the sample set against the capacity fade after 50 cycles of a lithium coin cell that includes a lithium negative electrode and the lithium cobalt oxide as the positive electrode material and that is cycled between 3.0 and 4.3V at a constant current of C/3 during both charge and discharge cycles; and the values a, b and c are determined by using only the x.sub.i and y.sub.i values for Li.sub.w Co.sub.1-x A.sub.x O.sub.2+y compounds in the sample set that have a capacity fade after 50 cycles of less than or equal to 15%.

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