Fabrication Of Solid Oxide Fuel Cell's Electrodes By Plasma Spray And Research On Its Performances

Solid oxide fuel cell (SOFC) is an energy conversion device that produces electricity (and heat) directly from fossil fuels by electrochemical reactions. Being several advantages, such as higher energy conversion efficiency, no waste and all solid structure, SOFC has been the hotspot of scientific research today.The thin film electrode is an inevitable trend to realize the intermediate working temperature and to seek effective preparation methods. The plasma spraying is an advanced technology to prepare thin film due to high effectiveness and no limits of material selection. In this thesis, research was done aimed at the application of plasma spraying in the intermediate-temperature solid oxide fuel cell (IT-SOFC) and the correlated aspects. This paper got the following positive results by preparation on IT-SOFC with plasma spray and research on its performance.Metal supported nickel porous substrate was prepared successfully firstly by loose sintering. Nickel porous substrate possessed porosity of 36.95% and bending resistance of 102.4MPa. Its bending resistance can be improved to 160MPa and porosity be reduced to 30% above after a simulated working test of 100 hours at 750℃Composite anode and the electrolyte double-layer coatings were prepared by means of plasma spray on metal supported nickel porous substrate. Selected different anode powders material was sprayed. Its energy dispersion spectrum (EDS) results showed that nickel was volatilization during preparation when Ni/YSZ powder was used, so ideal anode was not formed. NiO/YSZ was better choice as anode prepared with it was obvious in scanning electric microscopy (SEM) images and its EDS results showed its composition matched require.Simulated high temperature condition experiments were done to electrodes. Their X ray diffractions(XRD) results showed it kept good stabilization after 100 hours at 750℃Simulated condition. SEM and EDS results showed each coat integrated well and a composition diffusion layer between anode and support substrate in a certain extent to increase its thermodynamics stability. Its bending resistance increased from 100MPa to 160MPa; its porosity reduced but met SOFC's require. Electrolyte's density was 94% and met SOFC's require.Gradually change of Matrix and coats'components can reduce their large thermal stress incased by their expansion coefficient's difference. Coating adhesion kept good quality after 5 circulations of thermal shock property, it revealed that design of gradient electrode structure can reduce thermal stress and improve adhesion strength between coating and supported matrix.