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

Abstract

Lithium cobalt oxide (LiCoO₂) 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(NO₃)₂, Li₂CO₃ and diformyl hydrazine fuel is heated to ignite at 350° C. This is accompanied by decomposition of cobalt nitrate and lithium carbonate to form LiCoO₂ within a few minutes, which is annealed at 850°C for 6 h to obtain an ordered-crystalline layered compound. The powder X-ray diffraction pattern of the prepared LiCoO₂ shows a hexagonal cell with a=2.81 and c=13.83 Å . Electrodes made with LiCoO₂, 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 LiCoO₂ synthesized in the present study.