Performance Investigation on Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Based Composite Cathode for Intermediate Temperature Fuel Cells
|School||Harbin Institute of Technology|
|Course||Condensed Matter Physics|
|Keywords||SOFC Composite cathode material BSCF - SSC BSCF - Ag Electrochemical properties|
The fuel cell is an electrochemical power generation device, can be efficient chemical energy directly into electrical energy, and environment-friendly, pollution, energy systems that rely on coal combustion, the fuel cell is a promising energy . Therefore, the development of fuel cells in recent years widespread concern. Many different types of fuel cells, solid oxide fuel cell (SOFC) solid oxide electrolyte with high efficiency, no corrosion, no leakage, simple battery installation equipment, etc., which is lacking in other fuel cell. SOFC is mainly constituted by a cathode, an anode, an electrolyte, and the connecting body, wherein as an important part of the cathode has a great effect on the performance of the SOFC. This thesis research work, carried out in temperature SOFC cathode material through complex means to improve the performance of the cathode, thus improving the output performance of the solid oxide fuel cell (SOFC). New cathode material Ba 0.5 Sr of 0.5 Co 0.8 Fe 0.2 the O 3-delta ??sub > (BSCF) is a very suitable for low temperature SOFC cathode material, it has the advantage of having a high oxygen diffusion coefficient at low temperatures, greatly reduces the operating temperature of the SOFC, but the main drawback of such a cathode material is an electron conductivity is relatively low, which to some extent limit its performance play and practical application, in order to overcome its shortcomings, this paper proposes a high conductivity were added on the basis of BSCF Sm 0.5 Sr the 0.5 CoO 3-δ (SSC) and Ag composite cathode materials to improve conductivity, to achieve the purpose of improving cathode performance. Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF) -Sm 0.5 Sr 0.5 CoO 3-δ (SSC) composite cathode performance. Solid mixed valid in the Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-delta < / sub> (BSCF) a certain proportion of composite SM 0.5 Sr 0.5 the CoO 3-8 (SSC), the formation of a porous composite cathode materials (BSCF-xSSC). XRD, high temperature resistance test and thermal expansion curve test; composite cathode materials using impedance spectroscopy and electrochemical polarization curves to study the electrochemical properties of these composites in the range of 500 to 800 ° C, to determine the incorporation of SSC on cathode of the performance. The test results showed that, through such a composite means not only to improve the electrical conductivity of the cathode, but also to improve the electrochemical properties of the cathode, wherein the BSCF-30wt.% SSC composite cathode, at 500 ° C near conductivity 176S · cm- 1, is about seven times that of pure BSCF; addition, electrochemical impedance spectroscopy BSCF-SSC performance is significantly better than pure BSCF, BSCF-30wt.% SSC performance in the 550 ° C, the total polarization resistance only 0.71? · cm2 is 1/7 of BSCF. This shows that a BSCF-xSSC composite cathode material more suitable for low temperature SOFC cathode. Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF) -Ag composite cathode performance. The Agno 3 solution impregnated decomposition method and solid mixed legal in Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-8 (BSCF) mixed with a certain amount of Ag formation of porous the BSCF-Ag composite cathode materials. XRD, high temperature resistance and electrochemical properties of the composite cathode material test. Electrochemical performance test results show that the use of impregnated Agno the BSCF-Ag 3 method to obtain composite cathode the BSCF-Ag polarization resistance of only 0.36Ω · cm at 650 ° C test < / sup>, about BSCF 27%; BSCF-20Ag legally obtained solid mixed polarization resistance of the 0.099Ω cm 2 sup>, approximately pure BSCF 1/5 The results show that BSCF-AG performance is also superior to the pure BSCF performance.