Microwave - Assisted Preparation Of Cobalt Tetraxide And Rare Earth Doped With

Co3O4 powder’s morphology, grain size and microstructure have a great impact on the physical and chemical properties and electrochemical, is the key factor to determining its performance. In this experiment, Co Cl2-6H2 O as raw materials, preparation of Co3O4 precursor by microwave assisted liquid phase precipitation.The research results show that(NH4)C2O4 as the precipitant can be obtained Co3O4 precursor with square structure, but conventional heating reaction is slow, and significant reaction in microwave assisted. Under the field of microwave assisted conditions, the optimum condition of preparation of Co3O4 precursor with square structure is: cobalt chloride as reactants ammonium oxalate as precipitation, reactant concentration of 0.1mol·L-1, the reaction temperature is 80℃, reaction time is 150 min. TG-DTA curve analysis of precursor(Co C2O4) showed that, in order to obtain Co3O4 powder, the thermal decomposition temperature should be between 500~850℃. In microwave-assisted heat treatment, the thermal decomposition temperature of 600℃, holding time of 60 min, to get crystal complete with a spherical shape nanometer Co3O4 powder.Efficient and uniform heating by means of microwave, can effectively prevent the phenomenon of sintering due to high-temperature solid phase method and significantly shorten the reaction time. On the basis of preparation Co C2O4, incorporation Ce ions, heat-treated in a microwave-assisted, preparation of Li Co1-xCexO2 materials, and to seek a new way preparation of lithium-ion battery cathode material of Li Co O2.The results show that Cerium ions incorporation not only change the precursor’s morphology, size, and also can affect Li Co1-xCexO2. Adoption microwave thermal decomposition, conditions for the preparation of better Li Co1-xCexO2 is: 60 min insulation at 500℃, grinding and holding 120 min at 800℃. Getting spherical and nanoscale particles Li Co1-xCexO2 powder. Through XRD analysis, it is mixed with Li Co O2, Li0.49 Co O2and Ce O2, that suggests incorporation cerium ions did not replace part of Co. Product by the electrochemical performance testing shows that its charge-discharge performance is good, with x=0.08 is the best, the initial discharge capacity of 205.1m Ah·g-1, Coulomb efficiency was 84.6%. After 50 cycles at 0.5C rate, Li Co0.92Ce0.08O2 material’s retention capacity was 87%.