Research On The Intermediate-Iemperature SOFC(Solid Oxide Fuel Cell)'s Electrolyte

The intermediate-temperature SOFC(Solid Oxide Fuel Cell)'s electrolyte with perovskite-type LSGM(La_0.9Sr_0.1Ga_0.8Mg_0.2O_3-δ) was synthesized using Advanced Pechini Method and Solidification Method. The thermal and electrical properties of the sintered samples(synthesized by two different methods) were measured and compared by Thermal Expansion and AC Impedance Spectroscopy; The phase transformation process and inner structure were measured and compared by XRD, DTA-TG and AC Impedance Spectroscopy. The research results show that the electrolyte synthesized by Advanced Pechini Method has several advantages, such as fine pre-powders, low sintering temperature, reduced or eliminated impurity phases and high conductivity etc. So, the APM is ideal method to synthesize LSGM.To increase the conductivity of the electrolyte, a new components for the electrolyte was designed. The perovskite-type Co-doped LSGMC8.5 (La_0.9Sr_0.1(Ga_0.9Co_0.1)_0.85Mg_0.15O_3-δ) were synthesized by Advanced Pechini method. The properties of LSGM and LSGMC8.5 were compared by the analysis of XRD, DTA-TG, Impedance spectra, conductivity and density. It showed that Co doping decreased the forming temperature of cubic perovskite structure from 1400℃to 1300℃, and increased the fractional density from 95%to 99%. The conductivity of the LSGMC8.5 sintered at 1400℃for 6h is 5.38×10-2S/cm. So the Co-doped LSGMC8.5 is more suitable for IT-SOFC.So, LSGMC_8.5(La_0.9Sr_0.1(Ga_0.9Co_0.1)_0.85Mg_0.15O_{3 -δ}) synthesized by Advanced Pechini Method is most suitable for intermediate-temperature SOFC(Solid Oxide Fuel Cell)'s electrolyte.