Nano-sized LiNi0.4Mn0.4Co0.2O2 lithium-ion battery cathode materials with and without dual Mg & Al doping were synthesized by Pechini method. The powdered materials were characterized using X-ray diffraction, scanning electron microscopy and electrochemical techniques. X-ray analyses showed that 003/104 peaks intensity ratio increased from 0.95 for undoped material to 1.27 for doped material, thereby suggesting that dual doping was beneficial in terms reducing Li/Ni cation mixing. Although dual doping caused some reduction in initial discharge capacity (140 vs. 128 mAh/g) and increase in charge transfer resistance relative to the undoped material, it noticeably helped increase capacity retention during battery testing at high voltage.