NiO/SDC纳米复合阳极粉体的制备

Preparation of NiO/SDC composite nanopowders for anode

利用柠檬酸-硝酸盐低温燃烧法制备了纳米级的SDC、NiO、复合NiO/SDC粉体,研究不同的制备方法对NiO/SDC复合阳极微观结构的影响。利用XRD、SEM对粉体的相组成、晶粒粒度及烧结体的相分布进行了表征。结果表明:柠檬酸与金属离子的摩尔比为1.5、氧化剂与还原剂的质量比为1.5时,NiO粉体的平均晶粒尺寸为25nm,NiO/SDC复合粉体中NiO、SDC的平均晶粒尺寸分别为20nm、15nm,在复合粉体中,NiO、SDC可以相互抑制对方晶粒的长大;当复合粉体在1 250℃保温2h时,纳米粉体机械混合法制备的NiO/SDC复合阳极的平均晶粒尺寸约为700nm,NiO、SDC在烧结体内分布不均匀;低温燃烧合成法直接制备的NiO/SDC复合阳极的平均晶粒尺寸<500nm,NiO、SDC形成连续的网状结构,NiO、SDC在烧结体内分布均匀。

Nanosized powders of SDC,NiO and composite NiO/SDC were prepared by low-temperature combustion synthesis method.The effect of the preparation processes on the microstructure of the NiO/SDC composite anode was studied.The phase composition of powders and the average grain size and the phase distribution of the sintered NiO/SDC composite anode were characterized by the XRD and SEM.The results show that when the mol ratio of the citric acid to the metal ions is 1.5 and the ratio of amount of oxidants to amount of the reductants is 1.5,the average grain size of NiO powder is 25nm and that of NiO powder and SDC powder in the NiO/SDC composite powder is 20nm and 15nm respectively.The grain growth of NiO and SDC is inhibited each other in the composite powder.The average grain size of the composite anode sintered at 1 250℃ for 2h is about 700nm when the composite powder is prepared by the mechanical mixing and the distribution of NiO and SDC is uneven.The average grain size of the sintered composite anode by the low temperature combustion,is less than 500nm and the distribution of NiO and SDC is even.