Solid-state synthesis and characterization of LiCoO2 and LiNi y Co1−y solid solutions

Solid solutions of compositions LiNi _y Co_1−y O₂ (y = 0.0, 0.1 and 0.2) were prepared by solid-state fusion synthesis from carbonate precursors. Material characterization was carried out using XRD. Formation mechanisms of the products are discussed in the light of TG/DTA results. Nickel-containing compositions gave higher discharge capacities and smaller hystereses in their charge-discharge profiles which make them more attractive than pristine LiCoO₂ as cathode materials in high-energy lithium cells. The lower loss in capacity per cycle for cells with unsubstituted LiCoO₂, as determined from cycling studies up to 25 cycles, makes it more suitable than the substituted ones for long cycle-life cells with low capacity fade.