表面修饰对La0.6Sr0.4Co0.2Fe0.8O3-δ阴极性能 及稳定性的影响研究

Impact of surface modification on the performance and stability of La0.6Sr0.4Co0.2Fe0.8O3-δ cathode

摘要:

本研究采用一步溶液浸渍法成功对La0.6Sr0.4Co0.2Fe0.8O3-δ（LSCF）表面进行了La2NiO4+δ（LNO）纳米颗粒修饰。扫描电镜分析显示，LNO纳米颗粒均匀分布在LSCF表面，颗粒粒径约在50-250 nm之间。电化学测试表明，与空白LSCF相比，修饰了LNO的阴极极化电阻降低了41%~50%，并且稳定性有明显提高：在750℃保温约125 h后，其极化电阻仅增大了50.42%，而空白LSCF阴极则增大了76.89%。X射线衍射分析表明在750℃保温100 h后LNO-LSCF表面出现了La2SrOx相。X光电子能谱分析表明，长期保温100 h后，LNO-LSCF阴极的表面Sr含量比保温前减少了3.66%，而空白LSCF阴极则增多了27.95%，说明通过表面修饰LNO成功抑制LSCF表面的Sr偏析。

关键词:固体氧化物燃料电池;表面修饰;LSCF;浸渍

Abstract:

Different concentrations of La2NiO4+δ (LNO) nanoparticles were decorated on La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) surface through one-step infiltration. Scanning electron microscope showed that LNO nanoparticles were distributed uniformly on LSCF surface, with a size range 50–250 nm. Electrochemical test revealed that compared with the bare LSCF, polarization resistance of LSCF cathode decorated with LNO particles reduced by 41%~50%, and its stability was improved, where its polarization resistance has increased by 50.42% after annealing at 750℃ for about 125 h while that of bare one increased by 76.89%. Evidenced by X-ray powder diffraction, La2SrOx phase appeared in LNO-LSCF after 100 h annealing, which was one of the possible reasons for enhanced stability. X-ray photoelectron spectroscopy showed that after annealing for 100 h, the surface Sr content decreased by 3.66% compared to that before annealing, whereas that of the bare one increased by 27.95%, indicating that LNO modification can effectively suppress Sr surface segregation of LSCF.

Key words:solid oxide fuel cells; surface modification; LSCF; infiltration