Comparative examination of LiyNixCo1-xO2 materials for lithium-ion battery cathodes

A number of LiyNixCo1-xO2 compounds were synthesised by means of solid-state annealing. The synthesis conditions (the raw components, temperature, duration) were optimized so that phases with y > 0.97 were obtained suitable for making positive electrodes for lithium-ionic batteries. The charge-discharge characteristics of such LiyNixCo1-xO2. electrodes were studied. The charging curves of several first cycles are slanted, the corresponding capacity reaches 120-130 mA·h/g. The capacity corresponding to further cycles essentially depends on x and y. The electrodes with x = 1 showed an obvious tendency to decrease their capacity in the course of cycling while the cobalt-containing compounds have more stable electrochemical characteristics. The materials based on mixed oxides of lithium, nickel and cobalt seem promising for making lithium-ionic battery cathodes from every viewpoint.