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 dip-coating 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.