Solid-state synthesis and characterization of LiNiyCo1-yO2 (0.0 <= y <= 0.4)

Quaternary oxides of compositions LiNiyCo1-yO2 (y = 0.0, 0.1, 0.2, 0.3 and 0.4) were synthesized using a solid-state route from carbonate precursors. Material characterization was carried out using XRD, FTIR and particle size analyses. The formation patterns of the products are discussed from TG-DTA results. Nickel-rich compositions gave higher discharge capacities and sma ller hysteresis in the charge-discharge cycling profiles which make them mo re attractive candidates than the unsubstituted LiCoO2 for use in high ener gy lithium-ion cells. However, the lower loss in capacity per cycle for cel ls with LiCoO2, as determined from charge-discharge studies up to 25 cycles , makes them more suitable than the substituted oxides for long cycle-life cells with low fade. (C) 2001 Published by Elsevier Science Ltd.