| Solid oxide Fuel cell (SOFC) is a kind of high efficient and clean energy conversion device, and so called Green Cell in 21centry.However, as the core part of fuel cell, traditional electrolyte Y2O3-stabled ZrO2 (YSZ) has low conductivity and high cost under 1000℃operating temperature. At present, a novel low/intermediate temperature solid oxide fuel cell (ITSOFC) has been received much attention in recent years in the intermediate temperature 400600℃which result in low cost, good stabilization, long life-span. It will be the SOFC trend in future.The thesis studies electrolytes of oxygen ion/proton mixed conducting DCO-salt composites (CSC).Low cost is the key to the production. So this paper discusses the technic of preparation of nano-SDC-carbonate electrolyte, material property, conductivity, and electrical property :1. At first the technology of preparation of SDC has been optimized: Using carbonate coprecipitation method to prepare SDC by back titration under the Na2CO3 controlling pH=8 will form even particles , less agglomerate. An ultrasonic cell crack device is used to crack the stick-particles into divided ones which reached nano-scale. Press them into pellets to test relative density,and achieved 96.44% in 1300℃. 2. The relative density is the key aspect of electrolyte material property.hydrogen penetration experiment was applied to characterize the relative density of pellets.Preparing SDC-(Li/Na)2CO3 and measure the hydrogen penetration flux below 600℃when changing the content of carbonate,then cetificate that 20%carbonate achieved high density and permeance is 2.85*10-6 mol/m2*s*Pa.3. A electrolyte support SOFC is prepared whose structure is: Ag (paste) /mixed electrode*/electrolyte/mixed electrode/Ag (paste). In 550℃,a high-performance 1.12W/cm2,open circuit voltage 1.065v, short circuit current 3093mA/cm2 are got. A new membrane technic with coating and heat pressure is used. Cell gets 272mWcm-2.4. The first time measuring electrolyte direct current conductivity by Wagner polarization method. Traditional measurement about conductivity is always reflected total conductivity in pellets, but can not show each part ratio. This method reflected H+/ O2- conductive property directly.In 450-550℃, H+ conductivity was 2-4 multiple higher than O2-.Faraday law is also used to calculate the ultimate polarization time. |
