Japanese Researchers Achieve Breakthrough in Proton Conductivity for Clean Energy

Japanese researchers have developed a new ceramic material that demonstrates record-high proton conductivity at intermediate temperatures while maintaining chemical stability. This breakthrough addresses a key challenge in efficient hydrogen-to-electricity conversion, which is critical for hydrogen-based clean energy technologies.

Few existing materials combine both chemical stability and efficient proton conductivity at these temperatures (200−400 °C), a problem known as the "Norby gap".

Addressing the "Norby Gap"

Conventional ceramic proton conductors often use acceptor doping, which can lead to "proton trapping," reducing conductivity at intermediate temperatures. This limitation has hampered the development of more efficient hydrogen-based energy systems.

Overcoming Conventional Limitations

The research team, led by Professor Masatomo Yashima from the Department of Chemistry at Institute of Science Tokyo, utilized an innovative donor co-doping strategy to circumvent these issues.

The Innovative Donor Co-Doping Strategy

The approach involved introducing two donor elements, molybdenum and tungsten, into an oxygen-deficient mother material, BaScO2.5. Through a rigorous process involving solid-state synthesis, electrical measurements, neutron diffraction, and computer simulations, the team thoroughly studied the effects of this dual-donor co-doping.

Record-High Proton Conductivity and Stability

Unprecedented Performance

The perovskite-type oxide BaSc0.8Mo0.1W0.1O2.8 exhibited superprotonic conductivity, reaching 0.01 S/cm at 193 °C and 0.10 S/cm at 330 °C.

These conductivity values surpass those of conventional ceramic materials in this temperature range.

Mechanism of Success

The material's remarkable performance is attributed to a high concentration of mobile protons, which is enabled by numerous oxygen vacancies in the mother material. Crucially, the donor co-doping strategy also led to suppressed proton trapping, which effectively lowers the activation energy for proton migration.

Robust Chemical Stability

Additionally, BaSc0.8Mo0.1W0.1O2.8 demonstrated chemical stability in carbon dioxide, oxygen, and hydrogen environments, a vital characteristic for practical applications.

This study provides a new design principle for solid electrolytes. Its findings are poised to accelerate the development of next-generation protonic ceramic fuel cells, steam electrolysis cells, and other hydrogen-related energy technologies for a carbon-neutral society.