Protonic ceramic electrochemical cells for hydrogen production from seawater electrolysis

This study demonstrates hydrogen production from seawater electrolysis via protonic ceramic electrochemical cells (PCECs) for the first time. Using vapors generated from seawater, a state-of-the-art air electrode PrBa_0.5Sr_0.5Co_1.5Fe_0.5O_5+δ (PBSCF) shows a typical area-specific resistance of 0.269 Ω cm² with reasonable durability within a 100 h test at 600 °C, similar to those tests using pure water vapor. In addition, in seawater vapor at 600 °C, a PCEC with a cell configuration of PBSCF∣BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3−δ (BZCYYb)∣Ni-BZCYYb shows a typical peak power density of 1.388 W cm⁻² in a fuel cell (FC) mode and a current density of −2.392 A cm⁻² in an electrolysis cell (EC) mode. In addition, the cells show promising stability in seawater vapor (3% and 10% H₂O concentration) in EC mode when tested at −0.5 A cm⁻² at 600 °C. More importantly, the cells maintain a reliable hydrogen production rate and faradaic efficiency during the seawater electrolysis.