Performance of an annular solid-oxide fuel cell micro-stack array operating in single-chamber conditions

An annular micro-stack array consisting of four fuel cells has been fabricated and operated successfully in single-chamber conditions using a nitrogen-diluted oxygen-methane mixture as the operating gas. The single cells consist of a state-of-the-art porous NiO/Y₂O₃-stabilized ZrO₂ (YSZ) anode support, a YSZ electrolyte membrane and a modified La_0.7Sr_0.3MnO₃ (LSM) cathode. The annular configuration of the array is favorable for utilizing the heating effect. The maximum power output of the annular stack decreases with increasingCH₄/O₂ ratio. Its performance increases with increasing CH₄ flow rate and decreases with increasing N₂ flow rate. The power output of the stack is ∼380 mW at CH₄/O₂ = 1 and an N₂ flow rate of 100 sccm and the average maximum power density of each cell is ∼190 mW cm⁻². The average performance of each cell in the annular micro-stack array is higher than that of an additional single cell placed next to the stack.