Hybrid-solid oxide electrolysis cell: A new strategy for efficient hydrogen production

Water electrolysis based on a solid oxide electrolysis cell (SOEC) has potential to be cost-effective, environmentally friendly, and highly efficient for hydrogen production. There are two types of SOECs, depending on electrolyte materials: oxygen ion conducting SOECs (oxygen-SOECs) and proton conducting SOECs (proton-SOECs). Here we report our new findings in exploring a SOEC based on a mixed-ion conductor that can transport both oxygen ion and proton at the same time, which is denoted as “Hybrid-SOEC”. When BaZr0.1Ce0.7Y0.1Yb0.1O3-δ was used as an electrolyte, the Hybrid SOEC shows the highest efficiency, demonstrating a current density of 3.16 A cm−2 at 1.3 V and 750 °C in 10% humidified hydrogen at hydrogen electrode and 10% humidified air at air electrode. Moreover, the Hybrid SOEC exhibits no observable degradation in performance for more than 60 h of continuous operation, implying a robust system for hydrogen production.