Investigation and optimization of high-valent Ta-doped SrFeO_(3-δ)as air electrode for intermediate-temperature solid oxide fuel cells  

作　　者：Shanshan Jiang Hao Qiu Shaohua Xu Xiaomin Xu Jingjing Jiang Beibei Xiao Paulo Sérgio Barros Juliao) Chao Su Daifen Chen Wei Zhou 

机构地区：[1]School of Energy and Power,Jiangsu University of Science and Technology,Zhenjiang 212100,China [2]WA School of Mines:Minerals,Energy and Chemical Engineering,Curtin University,Perth WA6102,Australia [3]Institute of Analysis and Testing,Beijing Academy of Science and Technology,Beijing 100089,China [4]State Key Laboratory of Materials-Oriented Chemical Engineering,College of Chemical Engineering,Nanjing Tech University,Nanjing 211816,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2024年第9期2102-2109,共8页矿物冶金与材料学报（英文版）

基　　金：financially supported by the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.2018ND133J);the National Natural Science Foundation of China(Nos.22309067 and 22101150);the Natural Science Foundation of Jiangsu Province,China(No.BK20190965).

摘　　要：To explore highly active and thermomechanical stable air electrodes for intermediate-temperature solid oxide fuel cells(ITSOFCs),10mol%Ta5+doped in the B site of strontium ferrite perovskite oxide(SrTa_(0.1)Fe_(0.9)O_(3-δ),STF)is investigated and optimized.The effects of Ta^(5+)doping on structure,transition metal reduction,oxygen nonstoichiometry,thermal expansion,and electrical performance are evaluated systematically.Via 10mol%Ta^(5+)doping,the thermal expansion coefficient(TEC)decreased from 34.1×10^(-6)(SrFeO_(3-δ))to 14.6×10^(-6) K^(-1)(STF),which is near the TEC of electrolyte(13.3×10^(-6) K^(-1) for Sm_(0.2)Ce_(0.8)O_(1.9),SDC),indicates excellent thermomechanical compatibility.At 550-750℃,STF shows superior oxygen vacancy concentrations(0.262 to 0.331),which is critical in the oxygen-reduction reaction(ORR).Oxygen temperature-programmed desorption(O_(2)-TPD)indicated the thermal reduction onset temperature of iron ion is around 420℃,which matched well with the inflection points on the thermos-gravimetric analysis and electrical conductivity curves.At 600℃,the STF electrode shows area-specific resistance(ASR)of 0.152Ω·cm^(2) and peak power density(PPD)of 749 mW·cm^(-2).ORR activity of STF was further improved by introducing 30wt%Sm_(0.2)Ce_(0.8)O_(1.9)(SDC)powder,STF+SDC composite cathode achieving outstanding ASR value of 0.115Ω·cm2 at 600℃,even comparable with benchmark cobalt-containing cathode,Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ)(BSCF).Distribution of relaxation time(DRT)analysis revealed that the oxygen surface exchange and bulk diffusion were improved by forming a composite cathode.At 650℃,STF+SDC composite cathode achieving an outstanding PPD of 1117 mW·cm^(-2).The excellent results suggest that STF and STF+SDC are promising air electrodes for IT-SOFCs.

关 键 词：strontium ferrite-based perovskite Ta doping composite cathode intermediate-temperature solid oxide fuel cells 

分 类 号：TM911.4[电气工程—电力电子与电力传动] TB34[一般工业技术—材料科学与工程]