Research On Key Issue On Hydreogy Production Combing Solar Energy And Low Temperature Of Solid Oxide Electrolysis Cells

Efficient,clean and sustainable energy become the focus of current energy research.Hybrid hydrogen production integrating solar energy and solid oxide electrolysis cell(SOEC)is a kind of energy conversion device with high performances.This thesis research mainly focus on the development of new material,cell performance and reversible reaction(solid oxide fuel cell,SOFC)SOEC and hybrid hydrogen production system.1)A new SOEC or SOFC with symmetric electrode was introduced based on the traditional SOEC or SOFC and its principle is studied in depth.Electrolyte materials of NSDC(Ce0.8Sm0.2O1.9-Na2CO3)the as-prepared composite are produced as well as the compatible electrode of the NCAL(Ni0.8Co0.15Al0.05LiO2-?)are selected.Based on the two types of materials,we designed and developed new SOEC.Under SOEC mode and current density arrived to 0.376A/cm2,the electrolyte voltage is 1.5V at 823K.On the other hand,under SOFC mode,the output power density reached to 0.804W/cm2.The results shown that the cell exhibit good electrochemical properties and symmetry both SOEC and SOFC.2)Electrolyte materials(NSDC)and electrode materials(NCAL)were mixed in certain ratio.A new semiconductor ion type cell was fabricated by the mixed powders.The results show that the performances of semiconductor ion type SOEC with a weight ratio of NSDC:NCAL=6:4 is better than that of pure NSDC.The operating temperature is higher,the electrolysis current density is greater and corresponding higher hydrogen production.In addition,the cell under both SOEC mode and SOFC mode exhibit good electrochemical properties and symmetry as well.3)Electrolyte materials(NSDC)and electrode materials(NCAL)were mixed in different ratio.The cell performances influenced by the different rations were analyzed in this cheaper.Semiconductor ion type cells were fabricated by the mixed powders.The effect of semiconductor material(NCAL)conductivity on the performance of the cell was studied.The results show that the cell performances are the best both in SOEC and SOFC mode with a weight ratio of NSDC:NCAL=6:4.The current density raise to 0.712A/cm2 under SOEC mode and the maximum output power of the cell run up to 1.071 W/cm2 under SOFC mode.4)A new hybrid hydrogen production system integrating solar energy and SOEC were constructed based on the classical SOEC hydrogen production system.It has realized the union plant by solar energy and SOEC.Thermodynamic model of solar,heat exchanger,SOEC,energy efficiency and exergy efficiency model were also built in this work.The effect of temperature and current on the performance of SOEC is studied based on the thermodynamic model.Analyzed results show that electrolysis potential decrease with temperature increase.Energy and exergy efficiencies were influenced by the operating temperature obviously for high current density.However,it is not very clear for low temperature.In the end,the exergy efficiency of photo energy-electrical energy/thermal energy is up to 25.7 in our solar hybrid system.Furthermore,the energy and exergy efficiencies have gone to 15.1%and 16.3%respectively by using the hybrid hydrogen production integrating solar energy and solid oxide electrolysis cell system.