Novel synthesis of stabilized Bi_(1-x-y)Gd_(x)Dy_(y)O_(1.5) solid electrolytes with enhanced conductivity for intermediate temperature solid oxide fuel cells(SOFCs)  

作　　者：Ahmed H.Ibrahim Yehia M.Abbas H.A.Ayoub Marwa H.Ali Mustafa Aldoori 

机构地区：[1]Materials Science Laboratory,Physics Department,Faculty of Science,Suez Canal University,41522,Ismailia,Egypt [2]Ministry of Higher Education and Scientific Research,Aliraqia University,10011,Baghdad,Iraq

出　　处：《Journal of Rare Earths》2024年第10期1903-1911,共9页稀土学报（英文版）

摘　　要：Herein,we report the synthesis of a Dy-Gd co-doped cubic phase-stabilized Bi_(2)O_(3) solid electrolyte system via solid-state processing under atmospheric conditions.Doping with Dy^(3+) and Gd^(3+) has been observed to significantly enhance the densification process during sintering for stabilization purposes,thereby improving the electrical properties of δ-Bi_(2)O_(3)-type polymorphs.The synthesized ceramics were characterized using X-ray diffraction(XRD),field emission scanning electron microscopy-energy dispersive X-ray spectroscopy(FESEM-EDX),thermal gravimetry/differential thermal analysis(TG/DTA),and the four-point probe technique(4PPT).XRD analysis reveals that the samples Bi_(1-x-y)Gd_(x)Dy_(y)O_(1.5)(y=0.05/x=0.05,0.10,0,15,and 0.20,and x=0.05/y=0.10,0.15,and 0.20) exhibit a stable face-centered cubic δ-phase and a mixed-phase crystallographic structure.The XRD analysis of the stabilized δ-phase suggests that the prepared oxides show a face-centered cubic(FCC) structure with a space group of Fm-3m.FESEM micrographs reveal that the composition Bi_(0.90)Gd_(0.05)Dy_(0.05)O_(1.5) has no significant holes.Nevertheless,an evident increase in the pore formation is observed as the amount of Gd_(2)O_(3) increases until it reaches 20%.This finding suggests that dense pellets are formed during the sintering process at 900-1000℃.The DTA analyses were performed to verify the phase stability,which agrees with the XRD results.The electrochemical performance of the synthesized Dy-Gd co-doped Bi_(2)O_(3)solid electrolyte system was evaluated and analyzed in detail by using the electrochemical impedance spectroscopy(EIS) technique,Based on EIS and conductivity measurements,Bi_(0.75)Gd_(0.20)Dy_(0.05)O_(1.5) exhibits the lowest activation energy of 0.519 eV and the highest conductivity value of 0.398 S/cm at 627℃compared to the other samples;this composition can be used as a solid electrolyte for intermediatetemperature solid oxide fuel cells(SOFCs).

关 键 词：Solid oxide fuel cells(SOFCs) Rare earths Solid-state processing RIETVELD Fast Fourier transform(FFT) Electrochemical impedance spectroscopy(EIS) 

分 类 号：TM911.4[电气工程—电力电子与电力传动] TQ174.1[化学工程—陶瓷工业]