The effect of simultaneous cobalt as well as aluminum doping was studied to understand their effect on the phase formation behavior and electrochemical properties of solution derived lithium nickel oxide cathode materials for rechargeable batteries. The discharge capacities of LiNi0.80Co0.20O2 and LiNi0.80Co0.15Al0.05O2 cathodes, measured at constant current densities of 0.45mAcm−2 in the cut-off voltage range of 4.3–3.2V, were 100 and 136mAhg−1, respectively. LiNi0.80Co0.15Al0.05O2 had better cycleability than the LiNi0.80Co0.20O2 cathodes. The retention of undesirable Li2CO3 phase both in LiNi0.80Co0.20O2 and LiNi0.80Co0.15Al0.05O2 cathodes was argued to be responsible for the relatively lower discharge capacity of these materials.