Preparation Of PrBaMn_1.8Pt_0.15Ni_0.05O_5+? Anode And Study On The Properties Of SOFCs

In recent years,global warming caused by the greenhouse effect has become more and more significant and has a greater impact on the global climate and natural ecosystems,and the excessive use of fossil fuels is one of the major causes.Solid oxide fuel cells(SOFCs)are devices that convert the chemical energy in gas directly into electrical energy.With their cleanliness,efficiency,wide fuel applicability and all-solid-state structure,SOFCs are considered the most commercially promising new energy technology.Conventional Ni/YSZ anodes suffer from severe carbon deposition and sulfur poisoning when using carbon-ammonia fuels,resulting in severe degradation of cell performance,and therefore new high-performance alternative anode materials need to be developed.Calcium titanite anodes,with good structural stability and strong resistance to carbon deposition and sulfur poisoning under reducing atmosphere,are a promising class of anode replacement materials.However,this class of materials suffers from poor catalytic activity,low ionic conductivity,poor redox structural stability,and unsatisfactory battery performance.In this thesis,a systematic study was conducted around the above problems.We applied the in situ precipitation technique to the chalcogenide materials,and designed and synthesized PrBaMn_1.8Pt_0.15Ni_0.05O_5+?anode materials by combining the crystal structure and elemental properties of the materials.The simple chalcogenide oxide Pr_0.5Ba_0.5Mn_0.9Pt_0.075Ni_0.025O_3-?was firstly prepared in air,followed by the in situ precipitation of Pt-Ni nanometallic catalytic particles on the surface of this material under reducing conditions to form a heterogeneous structure by mosaic on the surface of the chalcogenide parent.The material was transformed from simple chalcogenide to layered chalcogenide oxide,and the nanometallic particle-modified chalcogenide oxide anode material was obtained.PrBaMn_1.8Pt_0.15Ni_0.05O_5+?material exhibited excellent electrochemical catalytic activity towards hydrogen,and the single-cell power with its anode reached 1106.7 m Wcm^-2 in wet hydrogen at 850°C.The results showed that PrBaMn_1.8Pt_0.15Ni_0.05O_5+?material is a very promising anode material for high performance SOFCs.To further develop high-performance anode materials,we introduced electrostatic spinning technology into the preparation of PrBaMn_1.8Pt_0.15Ni_0.05O_5+?electrode materials by low-dimensionalizing nano(precipitated metal particles)micron(chalcogenide oxide matrices)heterostructures(collectively called nanomicroheterostructures)electrode materials.The fibrous structure has higher specific surface area and porosity,and the electrostatic spinning method achieves effective modulation of the nanostructure size and morphology of the electrode material compared with the conventional sol-gel method.The fibrous PrBaMn_1.8Pt_0.15Ni_0.05O_5+?electrode material has high electrical conductivity and excellent electrochemical catalytic performance,and the single-cell power density reaches 1414.0 m Wcm^-2 under humidified hydrogen at 850°C,which is a significant improvement over the electrode prepared by the sol-gel method.It is attributed to the high aspect ratio of the fiber-type material,which is favorable for electron transport.