Researchers succeed in building a low temperature hydrogen fuel cell, thanks to a scandium superhighway

Fukuoka, Japan—As global energy demand increases, researchers, industries, governments, and stakeholders are working together to develop new ways of meeting that demand. This is especially important as we address the ongoing climate crisis and transition away from fossil fuels.

One very promising type of energy generation is solid-oxide fuel cells, or SOFCs. Unlike batteries, which release stored chemical energy as electricity, fuel cells convert chemical fuel directly into electricity and continue to do so as long as fuel is provided. A common type of fuel cell many are familiar with is the hydrogen fuel cells, which convert hydrogen gas into energy and water.

While SOFCs are promising due to their high efficiency and long lifespan, one major drawback is that they require operation at high temperatures of around 700-800℃. Therefore, utility of these devices would require costly heat-resistant materials.

Now, publishing in Nature Materials, researchers at Kyushu University report that they have succeeded in developing a new SOFC with an efficient operating temperature of 300℃. The team expects that their new findings will lead to the development of low-cost, low-temperature SOFCs and greatly accelerate the practical application of these devices.

The heart of an SOFC is the electrolyte, a ceramic layer that carries charged particles between two electrodes. In hydrogen fuel cells, the electrolyte transports hydrogen ions (a.k.a. protons) to generate energy. However, the fuel cell needs to operate at the extremally high temperatures to run efficiently.

“Bringing the working temperature down to 300℃ it would slash material costs and open the door to consumer-level systems,” explains Professor Yoshihiro Yamazaki from Kyushu University’s Platform of Inter-/Transdisciplinary Energy Research, who led the study. “However, no known ceramic could carry enough protons that fast at such ‘warm’ conditions. So, we set out to break that bottleneck.”

Electrolytes are composed of different combinations of atoms arranged in a crystal lattice structure. It’s between these atoms that a proton would travel. Researchers have explored different combinations of materials and chemical dopants—substances that can alter the material’s physical properties—to improve the speed at which protons travel through electrolytes.

“But this also comes with a challenge,” continues Yamazaki. “Adding chemical dopants can increase the number of mobile protons passing through an electrolyte, but it usually clogs the crystal lattice, slowing the protons down. We looked for oxide crystals that could host many protons and let them move freely—a balance that our new study finally struck.”

The team found that two compounds, barium stannate (BaSnO3) and barium titanate (BaTiO3), when doped with high concentrations of scandium (Sc), were able achieve the SOFC benchmark proton conductivity of more that 0.01 S/cm at 300℃, a conductivity level comparable to today’s common SOFC electrolytes at 600-700℃.

“Structural analysis and molecular dynamics simulations revealed that the Sc atoms link their surrounding oxygens to form a ‘ScO₆ highway,’ along which protons travel with an unusually low migration barrier. This pathway is both wide and softly vibrating, which prevents the proton-trapping that normally plagues heavily doped oxides,” explains Yamazaki. “Lattice-dynamics data further revealed that BaSnO₃ and BaTiO₃ are intrinsically ‘softer’ than conventional SOFC materials, letting them absorb far more Sc than previously assumed.”

The findings overturn the trade-off between dopant level and ion transport, offering a clear path for low-cost, intermediate-temperature SOFCs.

“Beyond fuel cells, the same principle can be applied to other technologies, such as low-temperature electrolyzes, hydrogen pumps, and reactors that convert CO₂ into valuable chemicals, thereby multiplying the impact of decarbonization. Our work transforms a long-standing scientific paradox into a practical solution, bringing affordable hydrogen power closer to everyday life,” concludes Yamazaki.

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For more information about this research, see "Mitigating proton trapping in cubic perovskite oxides via ScO6 octahedral networks," Kota Tsujikawa, Junji Hyodo, Susumu Fujii, Kazuki Takahashi, Yuto Tomita, Nai Shi, Yasukazu Murakami, Shusuke Kasamatsu, and Yoshihiro Yamazaki Nature Materials, https://doi.org/10.1038/s41563-025-02311-w

About Kyushu University 
Founded in 1911, Kyushu University is one of Japan's leading research-oriented institutes of higher education, consistently ranking as one of the top ten Japanese universities in the Times Higher Education World University Rankings and the QS World Rankings. The university is one of the seven national universities in Japan, located in Fukuoka, on the island of Kyushu—the most southwestern of Japan’s four main islands with a population and land size slightly larger than Belgium. Kyushu U’s multiple campuses—home to around 19,000 students and 8000 faculty and staff—are located around Fukuoka City, a coastal metropolis that is frequently ranked among the world's most livable cities and historically known as Japan's gateway to Asia. Through its VISION 2030, Kyushu U will “drive social change with integrative knowledge.” By fusing the spectrum of knowledge, from the humanities and arts to engineering and medical sciences, Kyushu U will strengthen its research in the key areas of decarbonization, medicine and health, and environment and food, to tackle society’s most pressing issues.