Synthesis by molten salt and cathodic properties of Li(Ni1/3Co1/3Mn1/3)O2

Abstract

The mixed oxide, Li(Ni1/3Co1/3Mn1/3)O2, with the layer structure has been prepared by a one-pot method using the molten-salt mixture, LiNO3-LiCl at temperatures 750, 850 and 950 °C in air. The compounds were characterized by a variety of techniques. As per Rietveld data, only 4.0 and 2.5% of 'cation-mixing' was observed in the compounds prepared at 850 and 950 °C, respectively. Cyclic voltammetry with Li metal as counter electrode showed a clear indication of Ni2+/4+ redox couple at ∼3.6-3.9 V in all compounds. Charge-discharge cycling was carried out in the range 2.5-4.3, 2.5-4.4 and 2.5-4.5 V versus Li at a current rate of 20 or 30 mA g-1. The fifth cycle discharge capacities varied from 125 to 145 (±5) mA h g-1 for the compounds prepared at 850 and 950 °C. They exhibited excellent capacity-retention without noticeable capacity-fade till 50 cycles irrespective of the voltage cut-off. © 2006 Elsevier B.V. All rights reserved.