Study On The Preparation And The Electrochemical Properties Of Co₃O₄ Powder, As Positive Materials For Lithium-ion Batteries

At present the lithium-ion battery positive material mainly adopts LiCoO₂. As the important raw material to the high quality LiCoO₂, Co₃O₄ is depending on input in the home market.We try to adopt one method easy for industrialization to produce Co₃O₄ which has homogeneous diameter and non- reunion to satisfy the home market. The precursor of Co₃O₄ particles is synthesized through precipitation in this paper. Then the precursor is calcined to produce Co₃O₄ at a low temperature. The factors which affect the precipitation in the process of preparing the precursor are studied, and the suitable conditions for the reaction are designated. The thermal decomposition process of precursor is analyzed and the calcinations' temperature is confirmed by DTA curve. How the addition amount of surfactant affects dispersive result is analyzed by the means of XRD and SEM. According to the GB/T18287-2000 national standard, the properties of positive materials for lithium-ion battery are tested. The effect of difference grain size of Co₃O₄ to electrochemical properties of the positive material is analyzed and discussed.The results show: (1) The proper condition of preparing precursor is that the PH value is 6.5 , the temperature is 60℃ and the concentration of CoCl₂ is 0.1 mol/l-0.15mol/l. (2) The proper temperature is 400℃ and the time is 2 hours in the process of calcinations. (3) Adding the surfactant is benefit to prepare well dispersive Co₃O₄. The most proper recruitment of PEG is 0.8g/l, DBS is 1.6g/l, In general dispersible performance of DBS is better than PEG. (4) The positive materials have better cyclic stability and discharging specific capacity when the grain size of Co₃O₄ crystal is 200nm-300nm.