Abstract:
Intercalation cathode materials belonging to the 4-volt class electrodes, lithiated cobalt oxide
LiCoO2 and lithiated nickel cobalt oxide LiCo0.4Ni0.6O2, were synthesized by sol-gel technique.
The structural characteristics of the compounds were studied using XRD, FTIR and DSC. The
compounds were used as cathode materials for assembling rechargeable lithium-batteries and
their electrochemical performances were studied. The potentiostat and galvanostat techniques
were used to determine the electrochemical characteristics. The irreversible capacity loss of
LiCoO2 during the first charge-discharge is about 20% and for LiCo0.4Ni0.6O2 is about 90% for
two different current rates of 5 and 10 A kg-1. The overall electrochemical capacity of
LiCo0.4Ni0.6O2 has been drastically reduced due to the s-block or p-block metal substitution.
Also the un-reacted materials remained as impurities gave a very poor cycleability. However
more stable charge-discharge performances have been observed for LiCoO2 at different current
rates. Differences and similarities between these two cathode materials in batteries are also
discussed. The Li-ion batteries were assembled using the sol-gel synthesized cathode materials,
natural untreated vein graphite of Sri Lanka as the anode material and 1 M LiPF6 in EC/DMC
as liquid electrolyte, and their performances were tested.
