The Preparation And Performance Of Electrolyte-free Fuel Cells With Ion-Semiconductor Composite Membranes

Nowadays,with the scarcity of the resource on the earth,and the application of new energy sources seem to be particular importance.Therefore,people pay more attention on the solid oxide fuel cells.The characteristics of SOFC are green and non-pollution.However,with the wide using of solid oxide fuel cells,the shortcoming of three-layer fuel cells has gradually been found.For example,the thermal expansion coefficient of the cell layer needs to be matched well with each other,the working temperature of the fuel cell is too high,and the commercial application can not be realized because of the higher cost,and so on.These problems have limited the development of fuel cells.A new kind of fuel cell has been found which break through the limitations of the traditional solid oxide fuel cells.It is called electrolyte free fuel cell?EFFC?,because there is no traditional electrolyte layer in the cell.The main body of the fuel cell is the diaphragm layer in the center,which is composed by the semiconductor-ion composite material.Therefore,the selection of the semiconductor-ion composite material is very important.In this paper,we will choose two types of semiconductor material,which composite with the same ionic material respectively.The focus issue of the research is the impact of two semi-ion material on the new structure of fuel cells.The following is the main contents:1.One kind of semi-ion composite material is composed of Ce_0.9Gd_0.1O_2-?-Na₂CO₃?NGDC?and La_0.3Sr_0.7Fe_0.7Ti_0.3O_3-??LSTF?.The stability of crystal and the variation of ion-semiconducter composite were studied by XRD.The images of the ion-semiconducter composite material were observed by the electronic scanner microscope.The conductive process of composite materials was observed by electrochemical impedance spectroscopy.The experimental results are showed as following,there is no chemical reaction occurring in the NGDC-LSTF composite.The conductivity of the NGDC-LSTF composite play an important role in the EFFC.Thence the fuel cell which made from 50 wt.%LSTF and 50 wt.%NGDC,gives an OCV of 0.8 V at600?,and the maximum power density of EFFC is 654 mW·cm^-2.2.The other kind of semi-ion composite material is composed of Ce_0.9Gd_0.1O_2-?-Na₂CO₃?NGDC? and NdBa_0.5Sr_0.5Cu₂O_5+??NBSCu?.The stability of crystal and the variation of ion-semiconducter composite were studied by XRD.The images of the semi-ion composite material were observed by the electronic scanner microscope.The conductive process of composite materials was observed by electrochemical impedance spectroscopy.The experimental results are showed as following,the conductivity of the NGDC-NBSCu composite is higher than the NGDC-LSTF composite's.Therefore the electrical performance of the NGDC-NBSCu composite layer fuel cell is better.The fuel cell which made from 20 wt.%NBSCu and 80 wt.%NGDC,gives an OCV of 1.0 V at 600?,and the maximum power density of EFFC is 726 mW·cm^-2.