Ni/YSZ electrode degradation studied by impedance spectroscopy — Effect of p(H2O)

Abstract: Anode supported solid oxide fuel cells have been tested and the degradation over time was monitored and analyzed by impedance spectroscopy. Reproducibility of initial cathode, anode and electrolyte performance was obtained. Anode (Ni/YSZ) degradation was analyzed for tests applying p(H2O) of 0.2atm, 0.4atm and 0.6atm at 750°C and 0.75A/cm2. The anode degradation could be well described by the equation: R Ni,TPB(t)= R Ni,0 +ΔR∙(1−exp(− t / τ)). The initial resistance and total increase for the Ni–YSZ charge transfer resistance, R Ni,0 and ΔR, were similar for all tests (i.e. not directly correlated with p(H2O)), but the characteristic time, τ, for the anode degradation was significantly higher for the test at p(H2O)=0.2atm than at p(H2O) of 0.4atm and 0.6atm. [Copyright &y& Elsevier]