Breakthrough proton-conducting ceramic material for clean energy
Innovative co-doping strategy overcomes long-standing limits in proton conduction, opening a new way for efficient hydrogen-to-electricity conversion
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This study, based on a donor co-doping strategy to improve proton-conducting efficiency, could unlock their use in upcoming clean energy technologies involving hydrogen.
view moreCredit: Institute of Science Tokyo
A newly developed ceramic material shows record-high proton conductivity at intermediate temperatures while remaining chemically stable, report researchers from Japan. Efficient hydrogen-to-electricity conversion is critical for hydrogen-based clean energy technologies, but few materials combine chemical stability with efficient proton conductivity. Thanks to an innovative donor co-doping strategy, the proposed ceramic material features increased proton concentration and mobility, realizing exceptional conductivity and stability under CO2, O2, and H2 environments.
Hydrogen is widely regarded as a key pillar of future clean energy systems because it offers a way to store energy and generate electricity without carbon emissions. To achieve this vision, technologies that can efficiently convert hydrogen into electricity and vice versa, such as fuel cells and electrolyzers, are fundamental. In this context, protonic ceramic fuel cells have attracted attention as promising solutions, owing to their lower operating temperature compared to conventional solid oxide fuel cell systems, as well as their high theoretical efficiency.
Despite extensive research efforts, no ceramic material has demonstrated both efficient proton conductivity and long-term chemical stability at intermediate temperatures (200−400 °C) simultaneously—a problem known as the “Norby gap.” The challenge lies in how protons move through solid materials. Many ceramic proton conductors rely on acceptor doping, creating oxygen vacancies, enabling the hydration that forms protons. Although this strategy is effective in increasing proton concentration, it often gives rise to a phenomenon called “proton trapping,” whereby protons are trapped near dopant atoms rather than moving freely through the lattice. This trapping increases the energy barrier required for proton migration and sharply reduces proton conductivity at intermediate temperatures.
Fortunately, a research team led by Professor Masatomo Yashima from the Department of Chemistry at Institute of Science Tokyo (Science Tokyo), Japan, has now presented a compelling solution. A study published online in the journal Angewandte Chemie International Edition on January 19, 2026, reports the discovery of a novel ceramic material that breaks long-standing performance limits for proton conductors. Rather than using the conventional strategy of acceptor doping, the team explored a less-studied donor co-doping strategy. The proposed approach involved introducing two donor elements—molybdenum and tungsten—into an oxygen-deficient mother material BaScO2.5.
The researchers used solid-state synthesis and an extensive repertoire of analytical techniques, including electrical measurements, neutron diffraction, and computer simulations, to systematically study the effects of this dual-donor co-doping design on proton transport. They found that 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 substantially exceed those of conventional ceramic materials in this temperature region,” Yashima highlights.
Further analysis revealed that this performance comes from a combination of factors. The mother material BaScO2.5 contains a large number of oxygen vacancies that enable full hydration, leading to a very high concentration of mobile protons. At the same time, donor co-doping suppresses proton trapping by lowering the activation energy, allowing protons to move easily through the crystal lattice in three dimensions. Notably, the researchers also demonstrated that BaSc0.8Mo0.1W0.1O2.8 was chemically stable in CO2, O2, and H2 environments, highlighting its potential for practical applications.
By showing that donor co-doping can overcome fundamental limits in proton conductivity, this study opens a new path toward cleaner, more efficient hydrogen energy systems. “Our findings provide a powerful new design principle for realizing solid electrolytes that operate with high efficiency at intermediate temperatures. We expect this breakthrough to accelerate the practical development of next-generation protonic ceramic fuel cells, steam electrolysis cells, and other hydrogen-related energy technologies aimed at achieving a carbon-neutral society,” concludes Yashima.
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About Institute of Science Tokyo (Science Tokyo)
Institute of Science Tokyo (Science Tokyo) was established on October 1, 2024, following the merger between Tokyo Medical and Dental University (TMDU) and Tokyo Institute of Technology (Tokyo Tech), with the mission of “Advancing science and human wellbeing to create value for and with society.”
Journal
Angewandte Chemie International Edition
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
Superprotonic Conduction in Donor Co-Doped Perovskites
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