Work

Ultrafast proton transport phosphate for protonic ceramic electrolysis cells oxygen electrodes

Year: 2026

Type: preprint

Abstract: Protonic ceramic electrolysis cells can directly produce dry, pressurized green hydrogen at intermediate temperatures with an energy conversion efficiency approaching 100%, but slow proton transport in oxygen electrodes limits their large-scale deployment. The coupling between oxygen vacancy hydration and proton trapping fundamentally limits proton transport in perovskite oxides. Here we introduce Sr3(PO4)2 (SPO), a phosphate built from PO4 tetrahedra, into perovskite oxygen electrodes. Protons migrate between neighboring tetrahedra rapidly with a calculated barrier of only 0.15 eV. This phosphate pathway is independent of the perovskite host lattice and increases the proton chemical diffusion coefficient of SFM by nearly one order of magnitude.The in situ self‑assembly of SPO increases the electrolysis current density by up to 148% at 600 °C, and the best electrode achieves a current density of 2 A cm-2 at 600 °C and 1.3 V. Furthermore, this strategy demonstrates good universality for enhancing the performance of PCEC oxygen electrodes.

Source: Research Square

DOI: 10.21203/rs.3.rs-10593314/v1