以共沉法制备Ce_(0.8)M_(0.2)O_(1.9)固态电解质特性研究  

Preparation of Ce_(0.8)M_(0.2)O_(1.9) by Coprecipitation for Solid State Electrolyte

作　　者：林正雄[1] 傅彦培[2] 曾建玮[2] 

机构地区：[1]吴凤技术学院光机电暨材料研究所 [2]东华大学材料科学与工程系

出　　处：《武汉理工大学学报》2007年第10期109-112,共4页Journal of Wuhan University of Technology

摘　　要：以共沉法制备Ce0.8M0.2O1.9(M=La,Sm,Gd和Y)纳米粉末对于其结晶结构、显微特性及离子导电率进行探讨。粉末利用单轴压力机压制一丸形块材,所有试片以1 500℃持温5 h进行烧结,其密度皆高于90%理论密度。掺杂不同三价稀土元素到氧化铈基的固态电解质由XRD分析可知为立方萤石结构,因离子半径大小不同其主要绕射峰会有所偏移。在500—850℃之间进行Ce0.8M0.2O1.9(M=La,Sm,Gd和Y)离子导电率的量测,可发现掺杂Ce0.8Sm0.2O1.9有最大导电率(σ700℃=3.97×10-2S/cm)且有最小活化能Ea=0.637 eV,显示出掺杂的Sm3+与Ce4+的离子半径相近,其氧空缺具有最小的缔合焓。4种掺杂的三价稀土元素中,以Ce0.8La0.2O1.9的破裂韧性值最高(KIC=6.73 MPa.m1/2),代表掺杂三价镧可有效改善电解质的机械性质,当组装电池组件后,较能抵抗微裂缝(Mircocrack)的产生。The structure, microscopy and ionic conductivity of Ce0. 8 M0.2O1.9 （M = La, Sm, Cad and Y） nanopowder prepared by coprecipitation were investigated. The powders were pressed into pellets by uniaxial pressure. All sample were sintered at 1 500 ℃ for 5 h.The density of all specimens was over 90% of the theoretical density. According to the X-ray diffraction observation, it is found that all sample represent cubic fluorite structure. The shift in the main diffraction peaks is due to the dif- ferent ionic radius. The ionic conductivity of Ce0.8M0.2O1.9（M= La,Sm,Gd and Y） were measured in the temperature range of 500-850 ℃ ; the maximum ionic conductivity, σ700℃ = 3.97 × 10^-2 S/cm with minimum activation energy, Ea = 0. 637 eV was found for the Ce0.8Sm0.2O1.9. It exhibits that the radius of Sm^3＋ ion is similar to the ionic radius of the Ce^4＋ , which gives the minimum association enthalpy between dopant ion and oxygen vacancy. In this study, the maximum fracture toughness, KIC= 6.73 MPa·m^1/2 was found for the Ce0.8La0.2O1.9. It indicated that mechanical properties of lanthanum doped-ceria ceramic could be improved, which resists the mircocrack produces.

关 键 词：掺杂氧化铈 离子导电率 机械性质 

分 类 号：TM911[电气工程—电力电子与电力传动]