Zr^(4+)和Y^(3+)掺杂MCeO_3(M=Ca、Sr、Ba)质子导体的制备与表征

Preparation and characterization of proton-conducting solid electrolyte doped by Zr^(4+) and Y^(3+)

采用尿素燃烧法制备了Zr掺杂MCeO3(M=Ca、Sr、Ba)型钙钛矿质子固体电解质前驱体粉末,经X射线衍射(XRD)和热重差热(TG-DTA)分析可知,在600℃下煅烧前驱体粉末得到纳米级细小钙钛矿结构晶体,且该晶体在H2S气氛、700℃下保持化学稳定。粉末于200 MPa下等静压成型,高温烧结6 h后,固体电解质样品密度为理论密度的92%以上。利用恒电位仪测定3种电解质片CaCe0.9-xZrxY0.1O3(CCZY))、SrCe0.9-xZrxY0.1O3(SCZY)和BaCe0.9-xZrxY0.1O3(BCZY)(x=0.1~0.3)组成的水蒸气浓差电池,电动势可验证固体电解质的质子导电性的强弱,电池电动势的大小顺序为BCZY>SCZY>CCZY;且随着温度的升高,电动势逐渐增大,但达到700℃后,EMF值逐渐趋于平缓;在中温范围(500~750℃)内,BCZY的电导率最高可达到10-2S/cm以上,SCZY的也接近10-2S/cm,这有利于减小固体氧化物燃料电池的欧姆损失。

The urea combustion method was adopted to prepare proton conductor MCeO3 （M= Ca. Sr. Ba） precursor powders doped with Zr. From the XRD patterns and thermal analysis, 600 ℃ is the reasonable calcination temperature for MCeO3 to obtain fine powders with perovskite structure, which is stable in H2S atmosphere under 700℃. The solid electrolyte with 92% theory density are obtained after the powders were isostatically pressed at 200 MPa and then sintered for 6 h. The electromotive force （EMF） value of the steam concentration cell constructed by CaCe0.9-xZrxY0.1O3 , SrCe0.9-xZrxY0.1O3, BaCe0.9-xZrxY0.1O3 （noted as CCZY. SCZY. BCZY, respectively） as solid electrolyte were measured on potentiostat. The magnitude order of EMF value is BCZY〉SCZY〉CCZY, EMF value increases with the increase of temperature, and keeps steady at above 700 ℃. At 500 - 750 ℃, the biggest conductivity of BCZY reaches above 10^-2 S/cm, while that of SCZY approaches 10^-2 S/cm, which demonstrates that the two material are favorable for the reducing ohmic loss in the solid oxide fuel cell.