A novel synthetic route of A(x)CoO(2) (A = Li or Na) through the ion-exchange reaction of CoOOH by the hydrothermal method

LiCoO2 and NaxCoO2 were synthesized through the ion-exchange reaction of Co OOH using the hydrothermal method. The LiCoO2 single phase was obtained at 170 degrees C for 12h in LIOH solutions (greater than or equal to 0.1 mol/l ). The precipitated LiCoO2 had trigonal symmetry (R (3) over bar m) corresp onding to the high temperature phase of LiCoO2. The precipitate had a hexag onal plate-like shape and the size was between 100nm and 1.5 mu m Synthesis of NaxCoO2 single phase using the hydrothermal method was rather difficult , and NaxCoO2 was usually accompanied with secondary phase of Co3O4.