Electrostatic Spinning Preparation Of Ln < Sub > 2 < / Sub > Cuo < Sub > 4 < / Sub > Cathode Materials And Their Electrochemical Properties

Copper based K₂NiF₄type oxide materials exhibited mixed ionic and electronicconducting properties, high oxygen permeability and surface exchange coefficients,and compatible thermal expansion coefficient to CGO electrolyte material, whichmade this kind of materials as promising SOFC cathode materials candidate.In this paper, La_2-xSr_xCuO₄（x=0-0.5）nanofiber cathode materials were preparedby electrospinning method. The characterizations of materials have been completedby XRD, SEM, TG-DTA and TEM technique. The electrochemical property ofsynthesized materials is investigated by EIS analyzer.Nanofibers with different morphology are obtained and detailed formationmechanism is proposed. The results show that the morphology is controlled by thedifferent concentration of polymer and inorganic in precursor solution before spinning.The polarization resistances of the La₂CuO₄nanowire, nanotube and nanobelt weremeasured. The La₂CuO₄nanotube gave the lowest resistance of0.43Ω·cm²at750℃.In order to improve the electrochemical performance, La_2-xSr_xCuO₄（LSCO）nanotube cathode were prepared. The polarization resistance of this nanotubeelectrode is0.21Ω·cm²at750℃, and the rate limiting step changed with the oxygenpartial pressure: at lower oxygen partial pressures, the rate limiting step is the oxygenion migration between the TPB and the CGO electrolyte; at higher oxygen partialpressures, the rate limiting step is charge transfer process.Finally, in order to further optimize the performance, LSCO-Ag and LSCO-CGOcomposites are prepared. The best results was found in the LSCO-CGO with30%amount of CGO. The polarization resistance is0.17Ω·cm²at750℃,which is lowerpolarization resistance than LSCO electrode.