Novel solution-combustion synthesis of LiCoO2 and its characterization as cathode material for lithium-ion cells

Lithium cobalt oxide $(LiCoO_2)$ which is being widely used as cathode material in lithium-ion batteries is synthesized by a novel solution-combustion procedure. In this synthesis, a solution mixture of $Co(NO_3)_2, Li_2CO_3$ and diformyl hydrazine fuel is heated to ignite at $350^o\hspace{2mm}C}$. This is accompanied by decomposition of cobalt nitrate and lithium carbonate to form $LiCoO_2$ within a few minutes, which is annealed at $850^o\hspace{2mm}C}$ for 6 h to obtain an ordered-crystalline layered compound. The powder X-ray diffraction pattern of the prepared $LiCoO_2$ shows a hexagonal cell with a=2.81 and $c=13.83 \AA$. Electrodes made with $LiCoO_2$, acetylene black and poly(vinyledene fluoride) yield a discharge capacity of ~120 $mAh g^{-1}$ with good Faradaic efficiency over several charge–discharge cycles. Cyclic voltammetric and ac impedance data also corroborate the electrochemical activity of $LiCoO_2$ synthesized in the present study.