Abstract
Hydrogen production from water electrolysis is a key enabling energy storage technology for the large-scale deployment of
intermittent renewable energy sources. Proton ceramic electrolysers (PCEs) can produce dry pressurized hydrogen directly
from steam, avoiding major parts of cost-driving downstream separation and compression. However, the development of PCEs
has suffered from limited electrical efficiency due to electronic leakage and poor electrode kinetics. Here, we present the first
fully operational BaZrO3-based tubular PCE, with 10 cm2 active area and a hydrogen production rate above 15 Nml min−1. The
novel steam anode Ba1−xGd0.8La0.2+xCo2O6−δ exhibits mixed p-type electronic and protonic conduction and low activation energy
for water splitting, enabling total polarization resistances below 1 Ω cm2 at 600 °C and Faradaic efficiencies close to 100% at
high steam pressures. These tubular PCEs are mechanically robust, tolerate high pressures, allow improved process integration
and offer scale-up modularity.
intermittent renewable energy sources. Proton ceramic electrolysers (PCEs) can produce dry pressurized hydrogen directly
from steam, avoiding major parts of cost-driving downstream separation and compression. However, the development of PCEs
has suffered from limited electrical efficiency due to electronic leakage and poor electrode kinetics. Here, we present the first
fully operational BaZrO3-based tubular PCE, with 10 cm2 active area and a hydrogen production rate above 15 Nml min−1. The
novel steam anode Ba1−xGd0.8La0.2+xCo2O6−δ exhibits mixed p-type electronic and protonic conduction and low activation energy
for water splitting, enabling total polarization resistances below 1 Ω cm2 at 600 °C and Faradaic efficiencies close to 100% at
high steam pressures. These tubular PCEs are mechanically robust, tolerate high pressures, allow improved process integration
and offer scale-up modularity.