液相法制备条件对钴粉形貌和电化学性能的影响

Effect of Preparation Conditions on Morphology and Electrochemical Properties of Cobalt Powders

在室温下用液相还原法制备了单质钴粉末。采用XRD和SEM分析了粉末的相结构和微观形貌,并研究了表面活性剂的种类及浓度、钴源浓度和还原剂浓度对粉末最终形貌的影响。结果表明,引入PVA作为表面活性剂时,有利于形成球状结构,且PVA浓度越大,颗粒尺寸越小,颗粒分布越均匀。当PVA浓度为0.5%,水合肼浓度为80%,Co^(2+)浓度为2.5M时,所得样品呈花球状结构。恒流充放电测试结果表明,由该钴粉制备的电池负极材料样品具有较高的放电容量,最高可达533mAh/g,且高倍率放电能力良好,1500mA/g的电流密度下放电容量能达到331.4mAh/g。

Co powders were synthesized via liquid phase method at room temperature. The products were characterized by powder X-ray diffraction （XRD） and scanning electron microscopy （SEM）, and the effects of surfactant, Co2＋ and reductant on the morphology were discussed. The results show that when PVA was used as surfactant, Co powders prefer to form spherical shape. As the concentration of PVA turns higher, the sizes of particles turn smaller. When the concentration of PVA, N2H4· H2O and Coe＋ is 0.5%, 80% and 2.5M, respectively, the morphology of the product is flowery microspheres. The charge and discharge tests show that the highest discharge capacity is 533mAh/g. When the current density reaches 1500mA/g, the discharge capacity still remains at 331.4mAh/g.