In the relentless pursuit of sustainable energy solutions, the scientific community has reached an exciting breakthrough that could revolutionize the future of clean power generation. Researchers at Kyushu University in Fukuoka, Japan, have announced a major advancement in solid-oxide fuel cell (SOFC) technology, achieving efficient operation at significantly lower temperatures than previously possible. This finding not only promises to dramatically reduce the cost and complexity of SOFC systems but also accelerates the transition toward widespread adoption of hydrogen-based energy technologies.
SOFCs are electrochemical devices that convert chemical fuels directly into electricity, maintaining operation as long as fuel supply continues. Unlike traditional batteries that store and deplete energy, fuel cells continuously generate electricity, making them ideal for scalable and sustainable energy solutions. Hydrogen fuel cells are among the most famous types, producing electricity and water by oxidizing hydrogen gas. However, the current generation of SOFCs requires extremely high operating temperatures of roughly 700–800°C, which demands expensive, heat-resistant materials and limits their practical deployment.
The Kyushu University team, led by Professor Yoshihiro Yamazaki, has succeeded in breaking this long-standing barrier by developing SOFC electrolytes that function efficiently at about 300°C – less than half of the prior temperature requirement. This achievement is extraordinarily significant because it opens the door for the construction of fuel cells that are both more affordable and compatible with consumer-level applications. Until now, no ceramic electrolyte material could simultaneously offer high proton conductivity and perform well enough at such ‘intermediate’ temperatures.
At the core of the SOFC is its electrolyte – a ceramic medium responsible for transporting charged particles such as protons between electrodes during energy generation. Proton conductivity within the electrolyte is vital for fuel cell efficiency, yet achieving fast proton transport at lower temperatures has been a major technical challenge. Typically, materials that increase the concentration of mobile protons do so at the cost of blocking their pathways in the crystal lattice, thereby slowing the overall ion mobility. Balancing these contradictory factors has long been a hurdle in fuel cell material science.
In an elegant solution, the research team explored the doping of two specific perovskite oxides — barium stannate (BaSnO₃) and barium titanate (BaTiO₃) — with high levels of scandium atoms. These scandium ions substitute the host lattice atoms and create a unique structural environment that promotes proton mobility. What makes this discovery remarkable is that these compounds, when doped at high scandium concentrations, reached proton conductivities exceeding 0.01 S/cm at 300°C — a performance metric traditionally only seen in materials operating at much higher temperatures.
Their detailed structural analyses and molecular dynamics simulations unveiled how scandium incorporated into the crystal lattice form extensive networks of ScO₆ octahedra — essentially ‘highways’ for proton transport. These ‘ScO₆ highways’ feature wide conduction pathways with low energy barriers that allow protons to move rapidly and smoothly without being trapped. This softness and vibrancy within the lattice help prevent the common issue of proton trapping that has plagued heavily doped oxide electrolytes in the past.
The intrinsic softness of BaSnO₃ and BaTiO₃ also plays a pivotal role, as it allows these materials to integrate unusually high scandium concentrations without sacrificing structural integrity or hindering ion transport. This quality overturns the conventional wisdom that increasing the dopant level inevitably degrades proton mobility by clogging pathways. Instead, the findings outline a new design principle for crafting electrolytes that defy this trade-off.
This breakthrough could have far-reaching impacts beyond just lowering the operating temperature of SOFCs. The principle of creating interconnected octahedral networks to facilitate ionic conduction could be applied to other hydrogen-related technologies, such as electrolysis systems that produce hydrogen, hydrogen pumps used in fuel processing, and even catalytically driven reactors converting carbon dioxide into valuable chemical feedstocks. Therefore, the implications of this research extend deep into efforts to decarbonize industries and form a hydrogen-based circular economy.
Professor Yamazaki emphasizes that this transition from a scientific paradox — where proton conductivity was thought to be inversely proportional to dopant concentration — to a practical solution is transformative. By employing scandium-doped perovskites, it effectively advances us toward more affordable and scalable hydrogen fuel technologies. This will not only reduce greenhouse gas emissions but also promote energy security through decentralized and efficient power sources.
Moreover, by enabling SOFC functionality at around 300°C, the need for costly, heat-resistant components diminishes drastically. This makes the fabrication of smaller, lighter, and cheaper fuel cells feasible, which can integrate into a wide array of applications from portable electronics to residential energy generation. The potential for consumer-level hydrogen power systems is particularly exciting, signaling a shift in how we produce and use clean energy.
The research, detailed in an upcoming issue of Nature Materials, showcases a multidisciplinary approach—blending experimental studies with advanced computational modeling—to comprehensively understand the atomic-scale mechanisms underpinning proton conduction. Such synergy exemplifies how modern material science leverages both theory and experiment to overcome longstanding technological roadblocks.
As the world intensifies its efforts to combat climate change and transition towards decarbonized energy systems, innovations like these are vital. The Kyushu University team has not only illuminated a path for next-generation SOFC electrolytes but also contributed foundational knowledge that may inspire further advances across energy materials. This work heralds a future where hydrogen-powered devices are more efficient, affordable, and closer to mainstream adoption.
In conclusion, by mitigating proton trapping and utilizing scandium’s unique structural role, this research offers a paradigm shift in the design of ceramic electrolytes for SOFCs. These findings represent a critical step toward realizing practical, intermediate-temperature fuel cells that could power everything from homes to industries, ushering a new era in sustainable and clean energy technology.
Subject of Research: Not applicable
Article Title: Mitigating proton trapping in cubic perovskite oxides via ScO6 octahedral networks
News Publication Date: 8-Aug-2025
Web References: http://dx.doi.org/10.1038/s41563-025-02311-w
References: Kota Tsujikawa, Junji Hyodo, Susumu Fujii, Kazuki Takahashi, Yuto Tomita, Nai Shi, Yasukazu Murakami, Shusuke Kasamatsu, and Yoshihiro Yamazaki, Nature Materials
Image Credits: Kyushu University/Yoshihiro Yamazaki
Keywords: Solid-oxide fuel cells, proton conductivity, scandium doping, perovskite oxides, barium stannate, barium titanate, intermediate-temperature fuel cells, proton transport, SOFC electrolyte, hydrogen energy, clean energy technology, energy transition
