Experimentation and Modelling of Nanostructured Nickel Cermet Anodes for Submicron SOFCs Fueled Indirectly by Industry Waste Carbon

Abstract

Nickel-Samaria Doped Ceria (Ni-SDC) cermet anodic thin films were prepared on Scandia Stabilized Zirconia (ScSZ) electrolyte supports by two distinct physical vapor deposition processes, 1) pulsed laser deposition (PLD) 2) radio frequency (RF) sputtering. For PLD, the deposition was carried out at a target temperature range of 0°C ~ 700°C. For RF sputtering, the target temperature was kept constant at room temperature of 25°C, however the background sputtering gas was either Ar or Ar:O2/80:20. Once the intended deposition conditions were established, the Ni-SDC anodes were deposited with a range of different sputtering powers (50W ~ 200W) and background Ar gas pressures (30mTorr ~ 90mTorr). The oxide conducting fuel cell configuration was completed by screen printing of lanthanum strontium manganite (LSM/YSZ) cathodes on the other side of ScSZ supports. Peak performance comparison of these cells was measured under hydrogen (H2) fuel source at an intermediate temperature range of 600°C ~ 800°C by voltage-current-power curves. The resistances of various cell components were observed by nyquist plots. Initial results showed that anode thin films made at increased target temperature, pressure, and high deposition power, performed better than the low powered ones, for a specific Ar or O2 pressure. Interestingly, however, anodes made at the highest power and the highest pressure, were not the ones that showed the maximum power output at an intermediate oxide fuel cell temperature range. Eventually, an optimal condition was reported for high performance thin film Ni-SDC anodes. These high performance anodes were then tested under an indirect carbon fuel source which utilizes raw unprocessed cheap carbon in a simple home-made gasifier. The carbon fuel source matched up to the H2 fuel in terms of a) peak power b) longevity c) lowered costs.