Synthesis of ultrofine LiCoO2 by citrate-nitrate gel combustion process

The ultrofine LiCoO2 powders were synthesized using LiNO3 and Co(NO33)2 · 6H2O as the starting materials and citrate acid as the fuel by the gel combustion process. Several analysis techniques were used to study the gel and the synthesized powders. It was found that the gel could be burnt at about 350-400 °C and the black and loose powders were easily obtained. XRD analysis shows that mild excess fuel was more in favor of the synthesis of LiCoO2 powders with fine crystallite size in comparison with stoichiometric fuel. After being calcined at 550 °C or above, the well-developed high temperature LiCoO2 phase was obtained. SEM and TEM observations show that the particle size of LiCoO2 is increased with the increase of calcination temperature. The size of LiCoO2 powders prepared by combustion process is much less than that prepared by solid-state reaction process.