Preparation Of Intermediate Temperature Cathode Materials And Performance Of SOFC

Solid oxide fuel cell （SOFC） is an electrode through the chemical reaction directly intoelectrical energy for continuous power generation devices, the traditional need for hightemperature SOFC （800℃¹000℃） work. However, working long hours at high temperaturecan trigger cell performance decay, while working under high temperature makes the materialpreparation process complexity, high cost, to bring some real difficulties in the commercial.Reducing the SOFC operating temperature is the current research trends.At the same time, the temperature dropped to below800℃, the traditional cathode materialLa_1-x（Sr,Ca）_xMnO₃sharply lower electrode activity is not suitable for the application of theITSOFC. Citrate method can not only reactive substances at the molecular level mixing, andheat treatment temperature low, the product of particle size small and distribution narrow, isan important synthetic method for inorganic powders.Therefore, this paper prepares La_0.7Sr_0.15Ca_0.15Co_1-xFe_xO₃-δ（x=0.2,0.4,0.6,0.8） cathodematerial by citrate method, studying the effect of Fe doped on La0.7Sr0.3-xCaxCo1-yFeyO3-δonstructure and properties of cathode material. And La_0.7Sr_0.15Ca_0.15Co_1-xFe_xO₃-δas cathode, LCNand electrolytes mixture as the anode，La_0.7Sr_0.15Ca_0.15Co_1-xFe_xO₃-δand composite electrolytes[Ce0.8Sm0.2O2-δ（SDC）�'�M₂CO₃（M=Na、Li）] mixture as the cathode， single cell is preparedby molding method, studying the effect of the La_0.7Sr_0.15Ca_0.15Co_1-xFe_xO₃-δcathode materialperformance on the battery performance in the hydrogen/air.The results show that Fe dopingon the open circuit voltage can not afford a decisive role in the high and low, open circuitvoltage is mainly affected by the mold and seal between the electrodes, gas flow rate,electrolyte and temperature. The maximum power density decreases from351.7mW/cm2to231.1mW/cm2when x increases from0.2to0.8at650℃.In order to study the optimal ratio of the adaptability of the cathodeLa0.7Sr0.15Ca0.15Co0.8Fe0.2O3-δ, Samarium doped ceria （SDC）electrolyte is prepared by acitrate method and forms CSC composite electrolyte with carbonate. The batteries based onSDC and CSC are prepared by molding method, and the performances of the two batteries arecomparatively evaluated in the hydrogen/air for researching the impact of SDC and CSC on battery performance. The results show that carbonate doped SDC reduces the battery opencircuit voltage, however, with the increase of temperature the open circuit voltage gap ofbatteries based on SDC electrolyte and CSC electrolyte is reduced from0.219V at500℃to0.007V at650℃. The maximum power density of battery based on CSC electrolyte is higher253.1mW/cm2than battery based on SDC electrolyte at650℃.In order to achieve ITSOFC cycling, not only has good output performance but also agood battery stability. The battery based on CSC composite electrolyte are prepared bymolding method, and in the process of heating and cooling cycle, the performance attenuationbehavior of the battery is evaluated in the hydrogen/air.The results show that with the increaseof temperature, the open circuit voltage and the maximum power density attenuation rate withthe increase in heating and cooling cycles gradually reduce and become gentle. The thirdheating and cooling cycle test compared with the first test，the attenuation rate of open circuitvoltage is reduced from40.60%at450℃to3.68%at650℃，and the attenuation rate of themaximum power density is reduced from72.44%at450℃to11.7%at650℃.