Study On Structure And Properties Of Intermediate Temperature SOFC With Silicon Based Composite Electrolyte

Intermediate temperature?500?-700??solid oxide fuel cells?SOFC?have become the main direction of commercial development.Exploit electrolyte materials in intermediate temperature with high ionic conductivity is the key to realize intermediate temperature for solid oxide fuel cell.It is considered as a kind of new electrolyte materials with great potential for development due to the new type of silicon based material with a single crystal structure has good ionic conductivity in the intermediate temperature condition.Si-based electrolyte powder Sr_0.7Na_0.3SiO_3-??Sr_0.7Li_0.3SiO_3-? was synthesized by Sol-Gel.The results showed that the material is a single phase material with a single crystal structure and particle uniformity.The particles size were between 100-200 nm.By the combination of Si-based materials and traditional electrolytes Zr_0.9Y_0.1O₂?YSZ?,when the ratio is 5:5 in weight dense electrolyte membrane was obtained at 1400? for 4 hours.This solves the problem that the single phase Si-base material is easy to collapse and can not be sintered densificate under high temperature.The chemical compatibility of Si-based electrolyte and electrode materials was studied.Anode material NiO and cathode material La_0.8Sr_0.2Co_0.8Fe_0.2O₃?LSCF?with perovskite structure were prepared by pyrolysis and co-precipitation method.Anode material NiO through the composite with Si-based electrolyte,porous structure can not be formed in composite anode.Results show that the Si-based material has good chemical compatibility with the anode material NiO.But a small amount of impurity phase was observed at 1000? for 2 hours with the cathode material LSCF.The composite anode?NiO:YSZ=7:3?,cathode materials and composite electrolyte materials?Si-based electrolyte:YSZ=5:5?are used to construct a anode supported single cell by co-pressing sintering?1400??and brushing re-sintering?1000??.Under the temperature of 550-650?,the anode is hydrogen,the cathode is air condition,the open circuit voltage of the battery reaches 1.08 V.The output power density of the battery is increased with the increase of temperature,which can reach 260 W/cm² at 650?.