Highly ionic-dispersed oxygen electrode for reversible proton ceramic electrochemical cells

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Commercialization of reversible proton ceramic electrochemical cells (R-PCECs) faces challenges due to low proton conductivity and poor thermomechanical stability of oxygen electrodes in humid air.
• Existing oxygen electrode materials struggle with water vapor, leading to performance degradation.

Purpose of the Study:

• To develop a multielement micro-doped BaCoO3-δ-based perovskite material for enhanced oxygen electrode performance in R-PCECs.
• To improve proton conductivity and thermomechanical stability for practical R-PCEC applications.

Main Methods:

• Fabrication of a multielement micro-doped BaCoO3-δ perovskite.
• Utilizing atom probe tomography and density functional theory (DFT) calculations to analyze material structure and properties.
• Performance testing of R-PCECs under fuel cell and electrolysis modes at 600°C.

Main Results:

• The doped perovskite exhibits induced disorder in the ionic substructure, maximizing oxygen-water reaction activity.
• DFT calculations confirmed reduced proton adsorption/diffusion energy barriers due to homogeneous ion distribution.
• The material demonstrated a peak power density of 1.56 W cm⁻² and electrolysis current density of 2.0 A cm⁻² at 1.3 V.
• Achieved long-term stability exceeding 780 hours with low degradation rates (19.3 μV h⁻¹ in fuel cell mode, 16.9 μV h⁻¹ in electrolysis mode).

Conclusions:

• The developed micro-doped perovskite material significantly enhances the performance and durability of R-PCECs.
• The material's design strategy addresses key challenges in R-PCEC commercialization, particularly oxygen electrode stability in humid environments.
• This advancement paves the way for more efficient and reliable proton ceramic electrochemical energy conversion and storage devices.