Lithium nickel cobalt oxides for positive electrodes

A lithium ion cell comprising:

• (a) a cell container;
• (b) a negative electrode provided within the cell container and capable of intercalating lithium during charge and deintercalating lithium during discharge, the negative electrode including a mixture of homogeneous graphitic carbon particles and homogeneous non-graphitic carbon particles;
• (c) an electrolyte conductive to lithium ions and provided within said cell container;
• and
• (d) a positive electrode provided within the cell container and capable of taking up lithium on discharge and releasing lithium on charge, the positive electrode including a mixture of (i) a chemical compound of the formula Li.sub.x Ni.sub.y CO.sub.z M.sub.n O.sub.2 having an .alpha.-NaCrO.sub.2 crystal structure, where M is selected from the group consisting of aluminum, titanium, tungsten, chromium, molybdenum, magnesium, tantalum, and combinations thereof, x is between about 0 and about 1 and can be varied within this range by electrochemical insertion and extraction, the sum of y+z+n is about 1, n ranges between about 0 to about 0.25, y and z are both greater than 0, and the ratio z/y ranges from above 0 to about 1/3, and (ii) a lithium manganese oxide chemical compound of the formula Li.sub.x Mn.sub.2-r M1.sub.r O.sub.4, where M1 is tungsten, titanium, chromium, or combinations thereof, and r ranges between about 0 and 1, wherein Li.sub.x Ni.sub.y Co.sub.z M.sub.n O.sub.2 and Li.sub.x Mn.sub.2-r M1.sub.r O.sub.4 are present in the positive electrode in a ratio of about 50:50.