Study On The Solid Electrolyte Of ZrO₂ Doped By Multi-elements

As a new way of power generation, Solid Oxide Fuel Cell (SOFC)has caused a wide attention in recent years. The development of IT-SOFChas been the hot issues and has become the tendency for the research anddevelopment of SOFC. In this paper, The ZrO2 doped by multi-elementswas studied, which made crystal lattice distorsion and enhanced theoxygen vacancy transfer passage radii and conductivity. This material isexpected to be used for the electrolyte of IT-SOFC.The ZrO2 electrolyte materials doped by multi-elements (Y2O3,Sc2O3, Dy2O3, Yb2O3, Al2O3 and CaO) were prepared byhigh-temperature solid-state method. The high-temperature conductivityof samples was enhanced remarkably, reaching 0.19S/cm at 1000°C, withthe total additives in the range of 8~8.6mol%. The aging property wasgood, the high-temperature conductivity (1000°C) remained about0.15S/cm after working for 900h. While the sinterability (relative density,~95%) and bending strength would be enhanced. It is expected thatsinterability and mechanical property can be further improved byinclusion of small amount of Al2O3 and/or CaO into the multi-elementsdoped ZrO2 materials. The addition of some amount of Al2O3 reduced theconductivity a little, but enhanced relative density (~2.3%) and bendingstrength (~30%) of samples respectively. The addition of some amount ofCaO reduced bending strength and conductivity (~50%) of samples.The same compositions samples were prepared by combustionsynthesis, in order to improve the samples sinterability further and makemulti-elements mix well. All properties of samples didn't show their ownadvantages due to the complexity of the reaction among all elements. Thehigh-temperature conductivity reached 0.15S/cm, but the relative density(~94%) and bending strength were lower than that the same compositionssamples prepared by high-tempreture solid-state method.