Performance Of NiTiO₃ Based Internal Reforming Direct Ethanol Fuel Cell

Solid oxide fuel cell（SOFC）is an efficient and clean energy conversion device that can efficiently convert chemical energy into electrical energy.but its commercialization process is limited by the construction cost of hydrogen refueling stations and hydrogen transportation.The use of environmentally friendly renewable resources-ethanol to replace traditional hydrogen energy to accelerate the commercialization of SOFC has been widely recognized.However,traditional nickel-based anodes will produce carbon deposits when ethanol fuel is used,which will lead to degradation performance and affect long-term operation of cell.By adding a catalytic reforming layer on the surface of the typical nickel-based anode,not only can the performance degradation caused by the direct contact of ethanol fuel with the anode be avoided,but also the catalytic reforming of ethanol can be promoted to improve the output performance of the cell.Therefore,this thesis takes NiTiO₃（NTO）-based materials as the research object,by adding ion conductive phase Gd_0.1Ce_0.9O_2-δ,and doping relatively inert Cu at the Nisite to promote the reforming reaction of ethanol fuel and reduce the carbon deposition on the anode surface.The main contents of this paper are as follows:（1）In view of the carbon deposition problem of typical nickel-based anodes,NTO powder was synthesized and its anti-carbon deposition performance was analyzed.The phase,XPS,conductivity,cell performance and reforming effect of NTO powder have been studied.The study found that NTO will decompose into Ni and TiO₂ in situ in a reducing atmosphere,it has high catalytic activity for ethanol fuel cracking and can reduce carbon deposits.The maximum power density of typical cell and NTO reforming layer cell at 800℃ were 705m W·cm^-2,937m W·cm^-2,respectively.In the long-term test under ethanol,the typical cell was completely destroyed after 7h,while the constant current output of the cell with NTO reforming layer remains stable within 20 hours.It shows that the cell with NTO reforming layer is superior to the typical cell in terms of electrochemical performance and long-term stability.（2）NTO composite Gd_0.1Ce_0.9O_2-δ（GDC）is used as a reforming layer to improve the long-term stability of the cell in an ethanol atmosphere.The chemical compatibility,electrical conductivity,cell performance and reforming effect of the two materials have been studied.The existence of GDC can improve the conductivity of oxygen ions and promote the catalytic reforming of ethanol.In an ethanol atmosphere,compared with the cell with NTO,NTO combined with GDC ion conductive phase can reduce the polarization impedance.In a long-term test under ethanol,the cell with NTO-GDC reforming layer maintains a stable constant current output within 20 hours.Compared with the cell with NTO reforming layer,the long-term stability is significantly improved.It shows that composite GDC can improve the long-term stability of the cell in ethanol atmosphere.（3）The Ni site in the NTO is doped with different content of Cu to prepare Ni_1-xCu_xTiO₃（x=0.1,0.2）reforming layer material to reduce the surface carbon of the anode.The phase,XPS,conductivity,cell performance and reforming effect of NTO powder have been studied.Studies have shown that the maximum power density of the cell with Ni_1-xCu_xTiO₃（x=0.1,0.2）reforming layer at 800℃ is 868m W·cm^-2,816m W·cm^-2 under ethanol atmosphere,respectively.The cell with Ni_0.9Cu_0.1TiO₃ reformed layer still has good long-term stability after 50h.The EDS picture shows that the carbon on the anode section is significantly reduced.It shows that Cu doping can improve the carbon deposition resistance of the anode.