Optimization of the electrode-supported tubular solid oxide cells for application on fuel cell and steam electrolysis

Hydrogen electrode-supported tubular solid oxide cells (SOCs) were fabricated by dipcoating and co-sintering method. The electrochemical properties of tubular SOCs were investigated both in fuel cell and electrolysis modes. Ni-YSZ was employed as hydrogen electrode support. The pore ratio of Ni-YSZ support strongly affected the performance of tubular SOCs, especially in steam electrolysis mode. The pore ratio was adjusted by the content of pore-former in support slurry. The results showed that 3 wt.% pore former content is the proper value to produce high performance both in fuel cell and electrolysis modes. In fuel cell mode, the maximum power density reached 743.1 mW cm 2 with H2 (105 sccm) and O2 (70 sccm) as working gases at 850 C. In electrolysis mode, as the electrolysis voltage was 1.3 V, the electrolysis current density reached 425 mA cm 2 with H2 (35 sccm) and N2 (70 sccm) adsorbed 47% steam as working gases in hydrogen electrode at 850 C. The stability of tubular SOCs was related to the ratio of NiO/YSZ in the support. The sample with NiO/YSZ ？ 60/40 shows a better performance than the sample with NiO/ YSZ ？ 50/50.