Revitalizing interface in protonic ceramic cells by acid etch.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Protonic ceramic electrochemical cells (PCECs) offer potential for low-temperature operation (<600°C).
• High bulk proton conductivity in electrolytes is often underutilized in full cells due to unknown limitations.
• Interfacial resistance at the electrode-electrolyte junction is a key challenge.

Purpose of the Study:

• To identify and address the causes of performance limitations in PCECs operating at lower temperatures.
• To improve the interfacial contact between the oxygen electrode and the proton-conducting electrolyte.
• To enhance the electrochemical performance and long-term stability of PCECs.

Main Methods:

• Investigated the role of the oxygen electrode-electrolyte interface in PCEC performance.
• Developed a simple acid treatment to rejuvenate the electrolyte surface.
• Characterized the interface using electrochemical impedance spectroscopy and performance testing.
• Evaluated fuel cell and electrolysis performance at various temperatures.

Main Results:

• Identified poor interfacial contact as the primary cause of performance loss.
• Acid treatment effectively restored the electrolyte surface, enabling strong bonding with the oxygen electrode.
• Achieved high power densities in fuel cell mode: 1.6 W cm⁻² at 600°C, 650 mW cm⁻² at 450°C, and 300 mW cm⁻² at 350°C.
• Demonstrated stable electrolysis with current densities >3.9 A cm⁻² at 1.4 V and 600°C.

Conclusions:

• Interfacial engineering is critical for optimizing PCEC performance.
• Acid treatment is a simple yet effective method to improve electrode-electrolyte contact and device efficiency.
• This approach enables high-performance PCECs for sustainable energy applications, including fuel cells and electrolysis, across a wide temperature range.