Electrochemical Study of the Versatility of a Solid Cell Working both as Fuel Cell and Electrolysis Modes

Abstract

Abstract A Ni/Yttria‐stabilized zirconia (YSZ) cell with a (La 0.60 Sr 0.40 ) 0.95 Co 0.20 Fe 0.80 O 3– δ cathode is tested both in fuel cell and electrolysis modes. In fuel cell mode under dry air and wet H 2 , the cell is operated between the open circuit voltage (OCV) and 0.4 V and reaches 330 mW cm −2 at 850 °C for 157 mL min −1 H 2 supply. The influence of temperature and air or hydrogen flow rate is studied, and impedance measurements show that below 0.8 V the electrolyte becomes the more resistive part of the cell. Nevertheless, fuel utilization yields are higher under oxygen or hydrogen depletion. If it is possible at 750 °C to work at low voltage during several hours in the entire voltage range, the voltage decrease must be limited at 850 °C. The cell can also be operated under wet air. The same cell can be operated in electrolysis mode, and a power density of 340 mW cm −2 can be obtained at 0.3 V/OCV under 100 mL min −1 wet (3% H 2 O) 5% H 2 –95% Ar mixture on the fuel side and dry or wet 100 mL min −1 air flow on the air side. Nevertheless, bubbling air providing the air electrode in saltwater has an irreversible detrimental effect on the cell.

Key findings

• ▸The cell's performance is influenced by temperature and air or hydrogen flow rate, with the electrolyte becoming the more resistive part of the cell below 0.8 V.
• ▸Fuel utilization yields are higher under oxygen or hydrogen depletion.
• ▸The cell can be operated under wet air and in electrolysis mode, with a power density of 340 mW cm⁻².

Keywords

Identifiers

DOI

10.1002/fuce.201900066

Journal

Fuel Cells

Year

2020