| Solid oxide fuel cells is an efficient and clean energy conversion device, electrolyte as its main component, designing and synthesising the low-temperature solid electrolyte materials is becoming a hot spot of current research. An important aspect of limiting its application for SDC electrolyte is the poorer sintering activity and enough difficult to sintering density under1500℃, therefore, many researchers work to improve SDC powder sintering activity and reduce the sintering temperature, the lab’s previous studies had found that transition metal doping can effectively improve the ceramic sintering activity of the billets. In this paper, respectively, alkaline earth metal transition metal Fe, Co, Ni doping on the material Smo.1Ceo.8Cao.1O1.9to study the influence of sintering activity and performance in the third chapter.BaZrO3perovskite proton conductor electrolyte material which has good chemical stability and high grains electrical conductivity, is one of the important candidate sofc electrolyte materials, but the downsides are high sintering temperature and the total conductivity is low. In the fourth chapter in this paper detailly studied that the impact doping Nd and Sm had on BaZrO3sintering performance and electric performance.In this paper, M (M=Fe, Co, Ni) doped composite Smo.1Ceo.79Ca0.1M0.01O1.9(M=Fe, Co, Ni) and not doped Smo.1Ceo.s Ca0.1O1.94kinds of oxygen ion conductor electrolyte materials and BaZro.s NdxSmo.2-x03-δ(x=0,0.05,0.1,0.15,0.2)6kinds of proton conductor electrolyte materials was prepared by the citric acid-nitrate self-propagating combustion synthesis.The material phase, microstructure and electric properties were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), Archimedes drainage method and ac impedance method.The chapter III results show Smo.1Ceo.79Cao.1M0.01O1.9(M=Fe, Co, Ni) and not doped Smo.1Ceo.8Cao.1O1.9electrolyte powder are prepared by the citric acid-nitrate combustion method, high temperature sintering to obtain the ceramic chip after molding. Sintering properties and electric properties of electrolyte was studied by doping different elements, XRD and SEM, respectively, had been used to characterize the phase and microstructure of the samples. Results show that ceramic powders after700℃for3h, as well as1250℃high temperature calcination, and present a single cubic fluorite phase structure; SEM showed that three sample billet of transition metal doping sintered after1250℃for5h has dense, Archimedes drainage method of determination of the relative density were over95%, showing that the doped with Fe, Co, Ni improve SDC electrolyte material sintering activity have obvious effect. Addition of Fe, Ni elements were not significantly affect the electrical conductivity of the material.The chapter Ⅳ results show that the BaZr0.8NdxSm0.2-xO3-δ(x=0,0.05,0.1,0.15,0.2) calcinated to single perovskite phase structure after1050℃～1100℃for5h. Sample billets increased grain size and porosity with the increase of sintering temperature, the relative density had above95%at about1450℃for5h, density has reached the requirements of various electrical test, showed that BaZrO3proton conductors substrate material sintering performance has improved byt doping Nd and Sm, the sintering temperature reduce by250℃. The conductivity test by Ac impedance method resulted show that,in500～800℃temperature range test, BaZr0.8NdxSm0.2-xO3-δ(x=0,0.05,0.1,0.15,0.2) had higher proton conductivity (800℃,10-3s. cm-1) t in the wet H2atmosphere, and proton conductivity of x=0.15is the biggest (1.46x10-3s. cm-1). It less affected by the temperature conductivity, showed that the proton transfer had lower activation energy than that of oxygen ion transport, in general, Nd and Sm doping can effectively improve BaZrO3proton conductor proton conductivity of matrix material. |
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